add, delete and partly update area

Code Android/meinWald/app/build.gradle

     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test.ext:junit:1.1.2'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
+    compile 'com.google.maps.android:android-maps-utils:0.6.2'
 
 }

Code Android/meinWald/app/src/main/AndroidManifest.xml

     package="com.example.meinwald">
 
     <application
-        android:name="com.example.meinwald.MyApplication"
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
             android:value="@string/google_maps_key" />
 
         <service
-            android:name=".ui.area.LocationTrack"
+            android:name=".ui.area.LocationService"
             android:exported="false">
         </service>
 

Code Android/meinWald/app/src/main/java/com/example/meinwald/MyApplication.java

-package com.example.meinwald;
-
-import android.app.Application;
-import android.content.Context;
-
-public class MyApplication extends Application {
-
-    private static Context context;
-
-    public void onCreate() {
-        super.onCreate();
-        MyApplication.context = getApplicationContext();
-    }
-
-    public static Context getAppContext() {
-        return MyApplication.context;
-    }
-}

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/area/AreaAdapter.java

 import android.app.AlertDialog;
 import android.content.Context;
 import android.content.DialogInterface;
-import android.graphics.Rect;
+import android.database.DataSetObserver;
+import android.os.Build;
 import android.util.Log;
 import android.view.Gravity;
 import android.view.LayoutInflater;
 
 import com.example.meinwald.BuildConfig;
 import com.example.meinwald.R;
-import com.example.meinwald.ui.task.OwnTask;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
 
 import java.util.ArrayList;
+import java.util.Date;
 import java.util.List;
 
-import androidx.appcompat.widget.AlertDialogLayout;
-import androidx.appcompat.widget.LinearLayoutCompat;
+import androidx.annotation.RequiresApi;
 import androidx.constraintlayout.widget.ConstraintLayout;
 
-import static java.security.AccessController.getContext;
-
 public class AreaAdapter extends BaseAdapter
 {
+    private final static String TAG = AreaAdapter.class.getSimpleName();
+
     List<OwnArea> areaList;
     LayoutInflater inflater;
     Context context;
+    boolean deleted = false;
+    Integer deletedPosition = null;
 
     public AreaAdapter(Context applicationContext, List<OwnArea> areaList)
     {
     }
 
     @Override
-    public View getView(final int i, View view, final ViewGroup viewGroup) {
+    public View getView(final int i, final View view, final ViewGroup viewGroup) {
 
-        view = inflater.inflate(R.layout.area_element, null);
-        final ConstraintLayout elementView = view.findViewById(R.id.areaElement);
-        final ConstraintLayout infovView = view.findViewById(R.id.areaInfoView);
-        final TextView title = (TextView) view.findViewById(R.id.areaInfoTitle);
-        final TextView notice = (TextView) view.findViewById(R.id.areaInfoNotice);
-        final ImageView icon = (ImageView) view.findViewById(R.id.areaIcon);
-        final ImageView manageArea = (ImageView) view.findViewById(R.id.areaManageArea);
+        final View areaView = inflater.inflate(R.layout.area_element, null);
+        final ConstraintLayout elementView = areaView.findViewById(R.id.areaElement);
+        final ConstraintLayout infovView = areaView.findViewById(R.id.areaInfoView);
+        final TextView title = (TextView) areaView.findViewById(R.id.areaInfoTitle);
+        final TextView notice = (TextView) areaView.findViewById(R.id.areaInfoNotice);
+        final TextView area = (TextView) areaView.findViewById(R.id.areaInfoArea);
+        final ImageView icon = (ImageView) areaView.findViewById(R.id.areaIcon);
+        final ImageView manageArea = (ImageView) areaView.findViewById(R.id.areaManageArea);
 
-        context = view.getContext();
-
-        if (BuildConfig.DEBUG)
-        {
-            Log.d("AreaAdapter",areaList.get(i).toString());
-            Log.d("AreaAdapter",areaList.get(i).getTitle());
-            Log.d("AreaAdapter",areaList.get(i).getNotice());
-        }
+        context = areaView.getContext();
 
         title.setText(areaList.get(i).getTitle());
         notice.setText(areaList.get(i).getNotice());
         icon.setImageBitmap(areaList.get(i).getImage());
 
+        if (areaList.get(i).getArea() != null)
+        {
+            area.setText(String. format("%.2f", areaList.get(i).getArea()) + " Quadratmeter");
+        }
+
         manageArea.setOnClickListener(new View.OnClickListener() {
+            @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
             @Override
             public void onClick(View v)
             {
                 final View viewInflated = LayoutInflater.from(v.getRootView().getContext()).inflate(R.layout.area_management, viewGroup, false);
 
                 builder.setView(viewInflated);
+                builder.setCancelable(true);
 
                 //get elements
                 TextView title = viewInflated.findViewById(R.id.areaManageTitle);
                 final TextView notice = viewInflated.findViewById(R.id.areaManageNotice);
                 TextView gpscount = viewInflated.findViewById(R.id.areaManageGPSPoints);
                 ImageView image = (ImageView) viewInflated.findViewById(R.id.areaManageImage);
+                final TextView lastChecked = viewInflated.findViewById(R.id.areaManagementLastChecked);
 
                 ImageView newNotice = (ImageView) viewInflated.findViewById(R.id.areaManageNewDescription);
                 ImageView newGPS = (ImageView) viewInflated.findViewById(R.id.areaManageNewGPS);
                 ImageView newImage = (ImageView) viewInflated.findViewById(R.id.areaManageNewImage);
                 ImageView deleteArea = (ImageView) viewInflated.findViewById(R.id.areaManageDeleteArea);
+                ImageView newDate = (ImageView) viewInflated.findViewById(R.id.areaManageNewDate);
 
-                //set current vlues
+                //set current values
                 title.setText(areaList.get(i).getTitle());
                 notice.setText(areaList.get(i).getNotice());
-                gpscount.setText(String.valueOf(areaList.get(i).getLocations().size()));
+                if (areaList.get(i).getCheckHistory() != null)
+                {
+                    lastChecked.setText(areaList.get(i).parseAndFormatLastCheckUpdate());
+                }
+
+                if (areaList.get(i).getLocations() != null)
+                {
+                    gpscount.setText(String.valueOf(areaList.get(i).getLocations().size()));
+                }
+                else
+                {
+                    gpscount.setText(String.valueOf(0));
+                }
+
 
                 if (areaList.get(i).getImage() != null)
                 {
                         newbuilder.setView(viewInflated);
 
                         final TextView noticeView = viewInflated.findViewById(R.id.areaManagementNoticeUserInput);
+                        noticeView.setText(areaList.get(i).getNotice());
 
                         newbuilder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
                             @Override
                         newbuilder.show();
                     }});
 
+                newDate.setOnClickListener(new View.OnClickListener() {
+                    @Override
+                    public void onClick(View v) {
+                        final AlertDialog.Builder newbuilder = new AlertDialog.Builder(v.getRootView().getContext());
+
+                        newbuilder.setTitle("Neu Kontrolle hinzufügen?");
+
+                        newbuilder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                                areaList.get(i).addCheckDate(new Date());
+                                lastChecked.setText(areaList.get(i).parseAndFormatLastCheckUpdate());
+
+                                //notifyDataSetChanged();
+
+                                if (BuildConfig.DEBUG) {
+                                    for (OwnArea area : areaList) {
+                                        Log.d(TAG, "areaList item: " + area.toString());
+                                    }
+                                }
+
+                                dialog.dismiss();
+                            }
+                        });
+
+                        newbuilder.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                                dialog.cancel();
+                            }
+                        });
+
+                        newbuilder.show();
+                    }});
+
+                    deleteArea.setOnClickListener(new View.OnClickListener() {
+                    @Override
+                    public void onClick(final View v) {
+                        final AlertDialog.Builder newbuilder = new AlertDialog.Builder(v.getRootView().getContext());
+
+                        newbuilder.setTitle("Das Grundstück wirklich löschen?");
+
+                        newbuilder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+
+                                areaList.get(i).deleteFromExternalStorage(context);
+                                areaList.remove(i);
+
+                                notifyDataSetChanged();
+
+                                if (BuildConfig.DEBUG)
+                                {
+                                    for (OwnArea area: areaList)
+                                    {
+                                        Log.d(TAG, "areaList item: " + area.toString());
+                                    }
+                                }
+
+                                dialog.dismiss();
+
+                                ((ViewGroup)viewInflated.getParent()).removeView(viewInflated);
+                                builder.show().cancel();
+                            }
+                        });
+
+                    newbuilder.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            dialog.cancel();
+                        }
+                    });
+
+                    newbuilder.show();
+                }});
+
+
 
                 builder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
                     @Override
                     public void onClick(DialogInterface dialog, int which) {
 
+                        if (areaList.size() > i && areaList.get(i) != null)
+                        {
+                            if (BuildConfig.DEBUG)
+                            {
+                               Log.d(TAG, "update area: " + areaList.get(i).toString());
+                            }
+                            areaList.get(i).deleteFromExternalStorage(context);
+                            areaList.get(i).writeToExternalStorage(context);
+                        }
+
+                        if (BuildConfig.DEBUG)
+                        {
+                            for (OwnArea area: areaList)
+                            {
+                                Log.d(TAG, "areaList item: " + area.toString());
+                            }
+                        }
+
                         dialog.dismiss();
+
                     }
                 });
 
             }
         });
 
-        return view;
+        return areaView;
+    }
+
+    public boolean isDeleted() {
+        return deleted;
+    }
+
+    public Integer getDeletedPosition()
+    {
+        return deletedPosition;
     }
 
     @Override

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/area/AreaFragment.java

 import android.app.AlertDialog;
 import android.content.DialogInterface;
 import android.content.pm.PackageManager;
+import android.database.DataSetObserver;
+import android.location.Location;
 import android.os.Bundle;
 import android.os.PowerManager;
 import android.preference.PreferenceManager;
 import com.example.meinwald.R;
 import com.google.android.gms.location.FusedLocationProviderClient;
 import com.google.android.gms.location.LocationServices;
+import com.google.android.gms.maps.CameraUpdateFactory;
 import com.google.android.gms.maps.model.LatLng;
+import com.google.android.gms.tasks.OnCompleteListener;
+import com.google.android.gms.tasks.Task;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 
 import org.json.JSONArray;
      * LOCATION
      */
     private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
+    /**
+     * The geographical location where the device is currently located.
+     * That is the last-known location retrieved by the Fused Location Provider.
+     */
+    private Location mLastKnownLocation;
     /**
      * The entry point to the Fused Location Provider.
      */
 
         //get saved areas
         allAreas = loadAreasFromPreferences();
+        for (int i = 0; i < allAreas.size(); i++)
+        {
+            allAreas.get(i).setPathFile(areaReferences.get(i).getPath());
+        }
         instantiateAreasList();
 
         PowerManager powerManager = (PowerManager) getContext().getSystemService(POWER_SERVICE);
                 AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
 
                 newArea = new OwnArea();
+                newPositions = new ArrayList<>();
 
                 final View viewInflated = LayoutInflater.from(getContext()).inflate(R.layout.area_input, (ViewGroup) getView(), false);
                 builder.setView(viewInflated);
 
                 final Button startTracking = viewInflated.findViewById(R.id.areaStartTracking);
                 final Button stopTracking = viewInflated.findViewById(R.id.areaStopTracking);
-
+                final Button addLocation = viewInflated.findViewById(R.id.areaAddGPSPoint);
 
                 startTracking.setOnClickListener(new View.OnClickListener() {
                     @Override
 
                         startTracking.setVisibility(View.INVISIBLE);
                         stopTracking.setVisibility(View.VISIBLE);
+                        addLocation.setVisibility(View.INVISIBLE);
                     }
                 });
 
                     public void onClick(View view) {
 
                         //stop tracking
-                        newPositions = gps.getPositions();
+                        List<LatLng> positionsToAdd = new ArrayList<>();
+                        positionsToAdd = gps.getPositions();
+
+                        for (LatLng pos: positionsToAdd)
+                        {
+                            newPositions.add(pos);
+                        }
 
                         if (BuildConfig.DEBUG)
                         {
                             Log.d(TAG, "Received locations: " + newPositions.size());
                         }
 
-                        newArea.setLocations(newPositions);
                         wakeLock.release();
 
                         startTracking.setVisibility(View.VISIBLE);
                         stopTracking.setVisibility(View.INVISIBLE);
+                        addLocation.setVisibility(View.VISIBLE);
                     }
                 });
 
+                addLocation.setOnClickListener(new View.OnClickListener() {
+                    @Override
+                    public void onClick(View view) {
+
+                        //get last known location
+                        getDeviceLocation();
+                    }});
+
                 builder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
                     @Override
                     public void onClick(DialogInterface dialog, int which) {
                             //save user input
                             newArea.setTitle(String.valueOf(titleView.getText()));
                             newArea.setNotice(String.valueOf(noticeView.getText()));
+                            newArea.setLocations(newPositions);
+                            newArea.calculateArea();
 
                             boolean result =  allAreas.add(newArea);
 
                                 Log.d(TAG, "add new task result: " + result);
                             }
 
-                            emptyPreferencesAndSaveAreaReferencesToPreferences();
+                            newArea.writeToExternalStorage(getContext());
+                            areaReferences.add(new AreaReference(newArea.getId(), newArea.getPathFile()));
 
-                            areaReferences.add(new AreaReference(newArea.getId(), writeAreaToExternalStorage(newArea)));
+                            emptyPreferencesAndSaveAreaReferencesToPreferences();
 
                             //actuate list
                             instantiateAreasList();
 
                 builder.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
                     @Override
-                    public void onClick(DialogInterface dialog, int which) {
+                    public void onClick(DialogInterface dialog, int which)
+                    {
+                        //reset variables
+                        newArea = new OwnArea();
+                        newPositions = new ArrayList<>();
+
                         dialog.cancel();
                     }
                 });
     public void instantiateAreasList()
     {
         final AreaAdapter adapter = new AreaAdapter(getActivity().getApplicationContext(), allAreas);
+        adapter.registerDataSetObserver(new DataSetObserver() {
+            @Override
+            public void onChanged() {
+                super.onChanged();
+
+                if (BuildConfig.DEBUG)
+                {
+                    Log.d(TAG, "onChanged");
+                }
+
+                if (BuildConfig.DEBUG)
+                {
+                    Log.d(TAG, "dataset size: " + areaList.getAdapter().getCount());
+                }
+
+                if (areaList.getAdapter().getCount() > 0)
+                {
+                    allAreas = new ArrayList<>();
+                    areaReferences =new ArrayList<>();
+
+                    for (int i = 0; i < areaList.getAdapter().getCount(); i++)
+                    {
+                        allAreas.add((OwnArea) areaList.getAdapter().getItem(i));
+                        if (BuildConfig.DEBUG)
+                        {
+                            Log.d(TAG, "dataset added: " + allAreas.get(i).toString());
+                        }
+
+                        areaReferences.add(new AreaReference(allAreas.get(i).getId(), allAreas.get(i).getPathFile()));
+                    }
+                }
+            }
+        });
         areaList.setAdapter(adapter);
 
         //initialise onClickListeners
         return areas;
     }
 
-    /**
-     * Save OwnArea object in textfile on external storage.
-     *
-     * @param newArea OwnArea object to write to file.
-     * @return
-     */
-    private String writeAreaToExternalStorage(OwnArea newArea){
-
-        if (BuildConfig.DEBUG)
-        {
-            Log.d(TAG, "writeAreaToExternalStorage()");
-        }
-
-        // Find the root of the external storage.
-        File root = android.os.Environment.getExternalStorageDirectory();
-
-        //create file if it does not exist
-        File path = new File (getContext().getFilesDir(),  "meinWald" + File.pathSeparator + "areas");
-        if(!path.exists()){
-            path.mkdirs();
-            if (BuildConfig.DEBUG)
-            {
-                Log.d(TAG, "Create new text file: " + path);
-            }
-        }
-        File file = new File(path, newArea.getId() + ".txt");
-
-        //open file and write to it
-        try {
-            FileOutputStream f = new FileOutputStream(file);
-            PrintWriter pw = new PrintWriter(f);
-            pw.print(areaToString(newArea));
-            pw.close();
-            f.close();
-        } catch (FileNotFoundException e) {
-            if (BuildConfig.DEBUG)
-            {
-                Log.e(TAG, "Failed write to external storage: " + e.toString());
-            }
-        } catch (IOException e) {
-            if (BuildConfig.DEBUG)
-            {
-                Log.e(TAG, "Failed write to external storage: " + e.toString());
-            }
-        }
-
-        return file.getPath();
-    }
-
     /**
      * Read OwnArea from file in external storage and return as a string.
      *
 
             while ((line = br.readLine()) != null) {
                 text.append(line);
+                if (BuildConfig.DEBUG)
+                {
+                    Log.d(TAG, "Line: " + line);
+                }
             }
             br.close();
         }
             String jsonString = PreferenceManager.getDefaultSharedPreferences(getContext()).getString(KEY_AREA_REFERENCES, "error");
             if(!"error".equalsIgnoreCase(jsonString)) {
                 JSONArray jsonObjects = new JSONArray(jsonString);
-                for (int i = 0; i<jsonObjects.length();i++) {
+                for (int i = 0; i<jsonObjects.length();i++)
+                {
                     areas.add(new AreaReference(jsonObjects.getJSONObject(i)));
+
+                    // Find the root of the external storage.
+                    File root = android.os.Environment.getExternalStorageDirectory();
+
+                    //delete reference if file does not exist
+                    File file = new File(getContext().getFilesDir(), "meinWald" + File.pathSeparator + "areas" + File.pathSeparator + areas.get(i).getId() + ".txt");
+                    if(file.exists())
+                    {
+                        areas.remove(i);
+                    }
                 }
             }
             else
     }
 
     /**
-     * Saves epicolors to preferences
+     * Saves areas to preferences
      */
     private void emptyPreferencesAndSaveAreaReferencesToPreferences()
     {
 
     }
 
+    /**
+     * Get the best and most recent location of the device, which may be null in rare
+     * cases when a location is not available.
+     *
+     */
+    private void getDeviceLocation() {
+        try {
+            if (mLocationPermissionGranted) {
+                Task<Location> locationResult = mFusedLocationProviderClient.getLastLocation();
+                locationResult.addOnCompleteListener(getActivity(), new OnCompleteListener<Location>() {
+                    @Override
+                    public void onComplete(@NonNull Task<Location> task) {
+                        if (task.isSuccessful())
+                        {
+                            // Set the last known position to the current location of the device and add to tracking stack
+                            mLastKnownLocation = task.getResult();
+                            newPositions.add(new LatLng(mLastKnownLocation.getLatitude(),mLastKnownLocation.getLongitude()));
+
+                            if (BuildConfig.DEBUG) {
+
+                                if (task.getResult() != null)
+                                {
+                                    Log.d(TAG, "getDeviceLocation: " + task.getResult().toString());
+                                    Log.d(TAG, "Size: " + newPositions.size());
+                                }
+                            }
+                        } else {
+                            if (BuildConfig.DEBUG) {
+                                Log.d(TAG, "Current location is null. Using defaults.");
+                                Log.e(TAG, "Exception: %s", task.getException());
+                            }
+                        }
+                    }
+                });
+            }
+        } catch (SecurityException e)  {
+            if (BuildConfig.DEBUG) {
+                Log.e(TAG, "Exception occurred: ");
+                e.printStackTrace();
+            }
+        }
+    }
+
     public void startLocationTracking(){
 
         final Runnable runnable= new Runnable() {

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/area/LocationService.java

     private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 5 meters
 
     // The minimum time between updates in milliseconds
-    private static final long MIN_TIME_BW_UPDATES = 1000 * 5 * 1; // 5 seconds
+    private static final long MIN_TIME_BW_UPDATES = 1000 * 1 * 1; // 5 seconds
 
     // Declaring a Location Manager
     protected LocationManager mLocationManager;
             Log.d(TAG, "onLocationChanged(), new location: " + location.toString());
         }
 
-        positions.add(new LatLng(location.getLatitude(), getLongitude()));
+        positions.add(new LatLng(location.getLatitude(), location.getLongitude()));
     }
 
     @Override

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/area/OwnArea.java

 package com.example.meinwald.ui.area;
 
+import android.content.Context;
 import android.graphics.Bitmap;
-import android.location.Location;
 import android.util.Log;
 
 import com.example.meinwald.BuildConfig;
 import com.google.android.gms.maps.model.LatLng;
+import com.google.maps.android.SphericalUtil;
 
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
-import java.sql.Time;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.text.SimpleDateFormat;
 import java.util.ArrayList;
+import java.util.Calendar;
 import java.util.Date;
 import java.util.List;
 
     private List<LatLng> locations;
     private Bitmap image;
     private String pathImage;
-    private String pathLocations;
+    private String pathFile;
     private String id;
+    private List<Date> checkHistory;
+    private Double area;
 
     public void setImage(Bitmap image) {
         this.image = image;
         this.pathImage = pathImage;
     }
 
-    public void setPathLocations(String pathLocations) {
-        this.pathLocations = pathLocations;
+    public void setPathFile(String pathFile) {
+        this.pathFile = pathFile;
+    }
+
+    public Double getArea() {
+        return area;
+    }
+
+    public void setArea(Double area) {
+        this.area = area;
+    }
+
+    public void calculateArea()
+    {
+        this.area = SphericalUtil.computeArea(this.locations);
     }
 
     public String getNotice() {
         return pathImage;
     }
 
-    public String getPathLocations() {
-        return pathLocations;
+    public String getPathFile() {
+        return pathFile;
     }
 
-    public OwnArea()
+    public List<Date> getCheckHistory() {
+        return checkHistory;
+    }
+
+    public void setCheckHistory(List<Date> checkHistory) {
+        this.checkHistory = checkHistory;
+    }
+
+    public void addCheckDate(Date newDate)
     {
+        if (BuildConfig.DEBUG)
+        {
+            Log.d(getClass().getSimpleName(), "add DATE");
+        }
+        if(this.checkHistory == null)
+        {
+            this.checkHistory = new ArrayList<>();
+        }
 
+        this.checkHistory.add(newDate);
+    }
+
+    public OwnArea()
+    {
+        this.title = null;
+        this.id = null;
+        this.notice = null;
+        this.pathFile = null;
+        this.image = null;
+        this.pathImage = null;
+        this.locations = new ArrayList<>();
+        this.checkHistory = new ArrayList<>();
     }
 
-    public OwnArea(String jsonString){
+    public OwnArea(String jsonString)
+    {
+        this.checkHistory = new ArrayList<>();
+        this.locations = new ArrayList<>();
+
         try {
             JSONObject areaObject = new JSONObject(jsonString);
             this.title = areaObject.getString("title");
                 }
             }
 
+            String historyString = areaObject.getString("history");
+            JSONArray history = new JSONArray(historyString);
+            this.checkHistory = new ArrayList<>();
+
+            for (int i = 0; i<history.length();i++) {
+                this.checkHistory.add(new Date(history.getJSONObject(i).getLong("date")));
+
+                if (BuildConfig.DEBUG)
+                {
+                    Log.d(getClass().getSimpleName(), "read location: " + this.checkHistory.get(i).toString());
+                }
+            }
+
+            if (this.locations != null && this.locations.size()>2)
+            {
+                calculateArea();
+            }
+
         } catch (JSONException e) {
             if (BuildConfig.DEBUG) {
                 Log.e(this.getClass().getSimpleName(),  "area json: " + jsonString);
         return id;
     }
 
+    /**
+     * Save OwnArea object in textfile on external storage.
+     *
+     * @return
+     */
+    public void writeToExternalStorage(Context context){
+
+        if (BuildConfig.DEBUG)
+        {
+            Log.d(getClass().getSimpleName(), "writeAreaToExternalStorage()");
+        }
+
+        // Find the root of the external storage.
+        File root = android.os.Environment.getExternalStorageDirectory();
+
+        //create file if it does not exist
+        File path = new File (context.getFilesDir(),  "meinWald" + File.pathSeparator + "areas");
+        if(!path.exists()){
+            path.mkdirs();
+            if (BuildConfig.DEBUG)
+            {
+                Log.d(getClass().getSimpleName(), "Create new text file: " + path);
+            }
+        }
+        File file = new File(path, this.getId() + ".txt");
+
+        //open file and write to it
+        try {
+            FileOutputStream f = new FileOutputStream(file);
+            PrintWriter pw = new PrintWriter(f);
+            pw.print(this.toJSONObject());
+            if (BuildConfig.DEBUG)
+            {
+                Log.d(getClass().getSimpleName(), "Json to write in file: " + this.toJSONObject().toString());
+            }
+            pw.close();
+            f.close();
+        } catch (FileNotFoundException e) {
+            if (BuildConfig.DEBUG)
+            {
+                Log.e(getClass().getSimpleName(), "Failed write to external storage: " + e.toString());
+            }
+        } catch (IOException e) {
+            if (BuildConfig.DEBUG)
+            {
+                Log.e(getClass().getSimpleName(), "Failed write to external storage: " + e.toString());
+            }
+        }
+
+        this.pathFile = file.getPath();
+    }
+
+    /**
+     * Delete OwnArea object textfile from external storage.
+     */
+    public void deleteFromExternalStorage(Context context)
+    {
+        if (BuildConfig.DEBUG)
+        {
+            Log.d(getClass().getSimpleName(), "deleteFromExternalStorage()");
+        }
+
+        // Find the root of the external storage.
+        File root = android.os.Environment.getExternalStorageDirectory();
+
+        //delete file if exists
+        File file = new File(context.getFilesDir(), "meinWald" + File.pathSeparator + "areas" + File.pathSeparator + this.getId() + ".txt");
+        if(!file.exists()){
+
+            file.delete();
+
+            if (BuildConfig.DEBUG)
+            {
+                Log.d(getClass().getSimpleName(), "Delete text file: " + file.getPath());
+            }
+        }
+
+    }
+
 
     /**
      * Returns OwnArea as JSONObject.
             //convert all locations
             JSONArray writeObjects = new JSONArray();
 
-            for (LatLng location: this.locations) {
+            if (BuildConfig.DEBUG) {
+                Log.d("OwnArea", "Save locations, locations size: " + locations.size());
+            }
 
-                JSONObject singleLocationObject = new JSONObject();
-                singleLocationObject.put("Lat", location.latitude);
-                singleLocationObject.put("Lng", location.longitude);
+            if (this.locations != null && this.locations.size() > 0)
+            {
+                for (LatLng location: this.locations) {
 
-                writeObjects.put(singleLocationObject);
+                    JSONObject singleLocationObject = new JSONObject();
+                    singleLocationObject.put("Lat", location.latitude);
+                    singleLocationObject.put("Lng", location.longitude);
 
-                if (BuildConfig.DEBUG) {
-                    Log.d("OwnArea", "added location object: " + singleLocationObject.toString());
+                    writeObjects.put(singleLocationObject);
+
+                    if (BuildConfig.DEBUG) {
+                        Log.d("OwnArea", "added location object: " + singleLocationObject.toString());
+                    }
                 }
             }
 
             object.put("locations", writeObjects.toString());
 
+            //convert all locations
+            writeObjects = new JSONArray();
+
+            if (BuildConfig.DEBUG) {
+                Log.d("OwnArea", "Save history, history size: " + checkHistory.size());
+            }
+
+            if (this.checkHistory != null && this.checkHistory.size() > 0)
+            {
+                if (BuildConfig.DEBUG) {
+                    Log.d("OwnArea", "history not empty");
+                }
+
+                for (Date date : this.checkHistory) {
+
+                    JSONObject singleHistoryObject = new JSONObject();
+                    singleHistoryObject.put("date", date.getTime());
+
+                    writeObjects.put(singleHistoryObject);
+
+                    if (BuildConfig.DEBUG) {
+                        Log.d("OwnArea", "added history object: " + singleHistoryObject.toString());
+                    }
+                }
+            }
+
+            object.put("history", writeObjects.toString());
+
+            if (area!=null)
+            {
+                object.put("area",this.area);
+            }
+            else
+            {
+                object.put("area", null);
+            }
+
             return object;
 
         } catch (JSONException e) {
             if (BuildConfig.DEBUG) {
                 Log.e(this.getClass().getSimpleName(),
-                        String.format("Error while parsing epiColorDto to JSONObject. Values of epiColorDto: %s", this.toString()));
+                        String.format("Error while parsing OwnArea to JSONObject. Values of OwnArea: %s", this.toString()));
             }
             return null;
         }
                 "title='" + title + '\'' +
                 ", notice='" + notice + '\'' +
                 ", pathImage='" + pathImage + '\'' +
-                ", pathLocations='" + pathLocations + '\'' +
+                ", pathLocations='" + pathFile + '\'' +
                 ", id='" + id + '\'' +
+                ", dates='" + checkHistory.size() + '\'' +
                 '}';
     }
+
+    /**
+     * Parses last check update from milliseconds to string and formats it to "dd.MM.yyyy hh:mm".
+     *
+     * @return date parsed and mapped as string representation
+     */
+    public String parseAndFormatLastCheckUpdate() {
+        SimpleDateFormat formatter = new SimpleDateFormat( "dd.MM.yyyy kk:mm");
+        Calendar calendar = Calendar.getInstance();
+        if (checkHistory != null && checkHistory.size()> 0)
+        {
+            calendar.setTimeInMillis(this.checkHistory.get(this.checkHistory.size()-1).getTime());
+        }
+        else
+        {
+            return "Keine Kontrolle vorhanden!";
+        }
+
+        return formatter.format(calendar.getTime());
+    }
+
+    public Long getLastChecked()
+    {
+        if (checkHistory != null && checkHistory.size()> 0)
+        {
+            return this.checkHistory.get(this.checkHistory.size()-1).getTime();
+        }
+        else
+        {
+            return (long) -1;
+        }
+    }
 }

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/map/MapsFragment.java

 import android.content.pm.PackageManager;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
+import android.graphics.Color;
 import android.location.Location;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ListView;
+import android.widget.Toast;
 
 import com.example.meinwald.BuildConfig;
 import com.example.meinwald.R;
 import com.example.meinwald.ui.area.AreaReference;
 import com.example.meinwald.ui.area.OwnArea;
 import com.example.meinwald.ui.task.OwnTask;
+import com.google.android.gms.common.util.Hex;
 import com.google.android.gms.dynamic.IObjectWrapper;
 import com.google.android.gms.location.FusedLocationProviderClient;
 import com.google.android.gms.location.LocationServices;
 import com.google.android.gms.maps.model.BitmapDescriptor;
 import com.google.android.gms.maps.model.CameraPosition;
 import com.google.android.gms.maps.model.LatLng;
+import com.google.android.gms.maps.model.Marker;
 import com.google.android.gms.maps.model.MarkerOptions;
+import com.google.android.gms.maps.model.Polygon;
+import com.google.android.gms.maps.model.PolygonOptions;
 import com.google.android.gms.maps.model.Polyline;
 import com.google.android.gms.maps.model.PolylineOptions;
 import com.google.android.gms.tasks.OnCompleteListener;
 import com.google.android.gms.tasks.Task;
+import com.google.maps.android.SphericalUtil;
 
 import org.json.JSONArray;
 import org.json.JSONException;
 import java.io.FileReader;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Date;
 import java.util.List;
 
 import androidx.annotation.NonNull;
         mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(getActivity());
 
         //wait for map is ready
-        mapFragment.getMapAsync(new OnMapReadyCallback() {
+        mapFragment.getMapAsync(new OnMapReadyCallback()
+        {
             @Override
             public void onMapReady(GoogleMap googleMap) {
                 //save map instance locally
                 mMap = googleMap;
                 //set max zoom level
                 mMap.setMaxZoomPreference(MAX_ZOOM);
+                mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
+                mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
+                    @Override
+                    public boolean onMarkerClick(Marker marker) {
+
+                        if (mMap.getCameraPosition().zoom < 17.5)
+                        {
+                            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(marker.getPosition().latitude, marker.getPosition().longitude),(float)17.5));
+                        }
+                        else
+                        {
+                            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(marker.getPosition().latitude, marker.getPosition().longitude),mMap.getCameraPosition().zoom));
+                        }
+
+                        return false;
+                    }
+                });
 
                 //retrieve saved instance state
                 mCameraPosition  = parseCameraPosition(PreferenceManager.getDefaultSharedPreferences(getContext()).getString(KEY_CAMERA_POSITION, new CameraPosition(new LatLng(45.0,11.0), (float) 1.0, (float) 0.0,(float) 0.0).toString()));
     {
         for (OwnArea area: allAreas)
         {
-
-            PolylineOptions options = new PolylineOptions().clickable(true);
-
-            for (LatLng location: area.getLocations())
+            if (area.getLocations() != null && area.getLocations().size()>0)
             {
-                options.add(location);
+                PolygonOptions options = new PolygonOptions().clickable(true);
 
                 if (BuildConfig.DEBUG)
                 {
-                    Log.d(TAG, "Position: " + location.toString());
+                    Log.d(TAG, "Color: " + getAreaColor(area.getLastChecked()));
+                    Log.d(TAG, "Color: " + String.valueOf(getAreaColor(area.getLastChecked() & 0x00FFFFFF) | 0x60000000));
+                    Log.d(TAG, "Area: " + SphericalUtil.computeArea(area.getLocations()));
+                }
+                options.strokeColor(getAreaColor(area.getLastChecked()));
+                options.fillColor((options.getStrokeColor() & 0x00FFFFFF) | 0x60000000);
+
+                for (LatLng location: area.getLocations())
+                {
+                    options.add(location);
+
+                    if (BuildConfig.DEBUG)
+                    {
+                        Log.d(TAG, "Position: " + location.toString());
+                    }
                 }
-            }
 
-            Polyline polyline1 = mMap.addPolyline(options);
+                options.add(area.getLocations().get(0));
 
+                mMap.addPolygon(options);
+            }
         }
     }
 
         drawAreas();
     }
 
+    /**
+     * Decides color of area based on the time passed since last ckeck update.
+     *
+     * @param time difference in milliseconds between last check and now
+     * @return color number
+     */
+    private int getAreaColor(long time) {
+        //set transparency related to time difference
+        if(time > -1)
+        {
+            long timeDiff = new Date().getTime() - time;
+
+            //less than a week
+            if (timeDiff < 7*24*60*60*1000L)
+            {
+                return  Color.parseColor("#57a639");
+            }
+            //less than two weeks
+            else if (timeDiff < 14*24*60*60*1000L)
+            {
+                return  Color.parseColor("#819b45");
+            }
+            //less than three weeks
+            else if (timeDiff < 21*24*60*60*1000L)
+            {
+                return  Color.parseColor("#d3d30c");
+            }
+            //less than four weeks
+            else if (timeDiff < 28*24*60*60*1000L)
+            {
+                return  Color.parseColor("#df9600");
+            }
+            //less than 6 weeks
+            else if (timeDiff < 42*24*60*60*1000L)
+            {
+                return  Color.parseColor("#df3d00");
+            }
+            //longer than four weeks
+            else
+            {
+                return  Color.parseColor("#f70000");
+            }
+        }
+        else
+        {
+            return  Color.parseColor("#f70000");
+        }
+    }
+
     /**
      * Request read external storage permission, so that we can get saved images from external storage.
      * The result of the permission request is handled by a callback,

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/task/OwnTask.java

 package com.example.meinwald.ui.task;
 
+import android.content.Context;
 import android.graphics.Bitmap;
 import android.location.Location;
 import android.media.Image;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
 import java.util.Date;
 
 public class OwnTask
 
     public void setPathImage(String pathImage) { this.pathImage = pathImage; }
 
+    public String saveImageToExternalStorage(Context context){
+
+        File path = null;
+
+        try {
+            path = new File(context.getFilesDir(), "meinWald" + File.separator + "Images");
+            if(!path.exists()){
+                path.mkdirs();
+            }
+
+            if (BuildConfig.DEBUG) {
+                Log.d(this.getClass().getSimpleName(), "Image file path: " + path);
+            }
+
+            File outFile = new File(path, this.id + ".jpeg");
+            if (!outFile.exists())
+            {
+                FileOutputStream outputStream = new FileOutputStream(outFile);
+                this.image.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
+                outputStream.close();
+            }
+
+        } catch (FileNotFoundException e) {
+            Log.e(this.getClass().getSimpleName(), "Saving received message failed with", e);
+        } catch (IOException e) {
+            Log.e(this.getClass().getSimpleName(), "Saving received message failed with", e);
+        }
+
+        return path.toString();
+    }
+
+    /**
+     * Delete OwnArea object textfile from external storage.
+     */
+    public void deleteFromExternalStorage(Context context)
+    {
+        if (BuildConfig.DEBUG)
+        {
+            Log.d(getClass().getSimpleName(), "deleteFromExternalStorage()");
+        }
+
+        // Find the root of the external storage.
+        File root = android.os.Environment.getExternalStorageDirectory();
+
+        //delete file if exists
+        File file = new File(context.getFilesDir(), "meinWald" + File.pathSeparator + "Images" + File.pathSeparator + this.getId() + ".txt");
+        if(!file.exists()){
+
+            file.delete();
+
+            if (BuildConfig.DEBUG)
+            {
+                Log.d(getClass().getSimpleName(), "Delete image file: " + file.getPath());
+            }
+        }
+    }
+
     @Override
     public String toString() {
         return "OwnTask{" +

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/task/TaskAdapter.java

 import android.content.Context;
 import android.content.DialogInterface;
 import android.graphics.Rect;
+import android.os.Build;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 
 import com.example.meinwald.BuildConfig;
 import com.example.meinwald.R;
+import com.example.meinwald.ui.area.AreaAdapter;
 import com.example.meinwald.ui.area.OwnArea;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 
 import java.util.ArrayList;
 import java.util.List;
 
+import androidx.annotation.RequiresApi;
 import androidx.appcompat.widget.AlertDialogLayout;
 import androidx.appcompat.widget.LinearLayoutCompat;
 import androidx.constraintlayout.widget.ConstraintLayout;
 
 public class TaskAdapter extends BaseAdapter
 {
+    private final static String TAG = TaskAdapter.class.getSimpleName();
+
     List<OwnTask> taskList;
     LayoutInflater inflater;
     Context context;
         final TextView title = (TextView) view.findViewById(R.id.taskInfoTitle);
         final TextView notice = (TextView) view.findViewById(R.id.taskInfoNotice);
         final ImageView icon = (ImageView) view.findViewById(R.id.taskIcon);
+        final ImageView manageTask = (ImageView) view.findViewById(R.id.taskManageTask);
         context = view.getContext();
 
 
             }
         });
 
+        manageTask.setOnClickListener(new View.OnClickListener() {
+            @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
+            @Override
+            public void onClick(View v)
+            {
+                final AlertDialog.Builder builder = new AlertDialog.Builder(v.getRootView().getContext());
+                final View viewInflated = LayoutInflater.from(v.getRootView().getContext()).inflate(R.layout.area_management, viewGroup, false);
+
+                builder.setView(viewInflated);
+
+                //get elements
+                TextView title = viewInflated.findViewById(R.id.areaManageTitle);
+                final TextView notice = viewInflated.findViewById(R.id.areaManageNotice);
+                TextView gps = viewInflated.findViewById(R.id.areaManageGPSPoints);
+                ImageView image = (ImageView) viewInflated.findViewById(R.id.areaManageImage);
+
+                ImageView newNotice = (ImageView) viewInflated.findViewById(R.id.areaManageNewDescription);
+                ImageView newGPS = (ImageView) viewInflated.findViewById(R.id.areaManageNewGPS);
+                ImageView newImage = (ImageView) viewInflated.findViewById(R.id.areaManageNewImage);
+                ImageView deleteArea = (ImageView) viewInflated.findViewById(R.id.areaManageDeleteArea);
+
+                //set current vlues
+                title.setText(taskList.get(i).getTitle());
+                notice.setText(taskList.get(i).getNotice());
+
+                if (taskList.get(i).getLocation() != null)
+                {
+                    gps.setText(String.valueOf(taskList.get(i).getLocation()));
+                }
+                else
+                {
+                    gps.setText("Kein Standort gespeichert!");
+                }
+
+                if (taskList.get(i).getImage() != null)
+                {
+                    image.setImageBitmap(taskList.get(i).getImage());
+                }
+
+                newNotice.setOnClickListener(new View.OnClickListener() {
+                    @Override
+                    public void onClick(View v)
+                    {
+                        final AlertDialog.Builder newbuilder = new AlertDialog.Builder(v.getRootView().getContext());
+                        final View viewInflated = LayoutInflater.from(v.getRootView().getContext()).inflate(R.layout.area_management_notice, viewGroup, false);
+
+                        newbuilder.setView(viewInflated);
+
+                        final TextView noticeView = viewInflated.findViewById(R.id.areaManagementNoticeUserInput);
+
+                        newbuilder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+
+                                taskList.get(i).setNotice(noticeView.getText().toString());
+                                notice.setText(taskList.get(i).getNotice());
+                                dialog.dismiss();
+                            }
+                        });
+
+                        newbuilder.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                                dialog.cancel();
+                            }
+                        });
+
+                        newbuilder.show();
+                    }});
+
+                deleteArea.setOnClickListener(new View.OnClickListener() {
+                    @Override
+                    public void onClick(View v) {
+                        final AlertDialog.Builder newbuilder = new AlertDialog.Builder(v.getRootView().getContext());
+
+                        newbuilder.setTitle("Das Grundstück wirklich löschen?");
+
+                        newbuilder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+
+                                taskList.get(i).deleteFromExternalStorage(context);
+                                taskList.remove(i);
+
+                                notifyDataSetChanged();
+
+                                if (BuildConfig.DEBUG)
+                                {
+                                    for (OwnTask task: taskList)
+                                    {
+                                        Log.d(TAG, "areaList item: " + task.toString());
+                                    }
+                                }
+
+                                dialog.dismiss();
+                            }
+                        });
+
+                        newbuilder.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
+                            @Override
+                            public void onClick(DialogInterface dialog, int which) {
+                                dialog.cancel();
+                            }
+                        });
+
+                        newbuilder.show();
+                    }});
+
+                builder.setPositiveButton("Bestätigen", new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+
+                        if (taskList.size()-1 > i && taskList.get(i) != null)
+                        {
+                            taskList.get(i).deleteFromExternalStorage(context);
+                            taskList.get(i).saveImageToExternalStorage(context);
+                        }
+
+                        if (BuildConfig.DEBUG)
+                        {
+                            for (OwnTask task: taskList)
+                            {
+                                Log.d(TAG, "areaList item: " + task.toString());
+                            }
+                        }
+
+                        dialog.dismiss();
+                    }
+                });
+
+                builder.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        dialog.cancel();
+                    }
+                });
+
+                builder.show();
+            }
+        });
+
         icon.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v)
                 final ConstraintLayout imageViewLayout = viewInflated.findViewById(R.id.taskLargeImageLayout);
                 final ImageView imageView = viewInflated.findViewById(R.id.taskLargeImage);
 
-                //ConstraintLayout.LayoutParams layoutParams = new ConstraintLayout.LayoutParams(taskList.get(i).getImage().getWidth(),5 * taskList.get(i).getImage().getHeight());
-                //imageViewLayout.setLayoutParams(layoutParams);
+                Log.d("TaskAdapter", String.valueOf(taskList.get(i).getImage().getHeight()));
+
+                //ConstraintLayout.LayoutParams layoutParams = new ConstraintLayout.LayoutParams(taskList.get(i).getImage().getWidth(), taskList.get(i).getImage().getHeight());
+                //layoutParams.width = taskList.get(i).getImage().getWidth();
+                //layoutParams.height = taskList.get(i).getImage().getHeight();
+                //imageView.setLayoutParams(layoutParams);
                 imageView.setImageBitmap(taskList.get(i).getImage());
 
                 builder.setNegativeButton("Zurück", new DialogInterface.OnClickListener() {

Code Android/meinWald/app/src/main/java/com/example/meinwald/ui/task/TasksFragment.java

 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.database.DataSetObserver;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.graphics.Color;
 
 import com.example.meinwald.BuildConfig;
 import com.example.meinwald.R;
+import com.example.meinwald.ui.area.AreaReference;
+import com.example.meinwald.ui.area.OwnArea;
 import com.google.android.gms.location.FusedLocationProviderClient;
 import com.google.android.gms.location.LocationServices;
 import com.google.android.gms.maps.CameraUpdateFactory;
 
                         //save and display location
                         newTask.setLocation(mLastKnownLocation);
-                        locationText.setText("Lat: " +String.valueOf(mLastKnownLocation.getLatitude()) + " Lng: " + String.valueOf(mLastKnownLocation.getLongitude()));
+                        locationText.setText("Auf " + newTask.getLocation().getAccuracy() + " Meter genau!");
                     }
                 });
 
                             //save user input
                             newTask.setTitle(String.valueOf(titleView.getText()));
                             newTask.setNotice(String.valueOf(noticeView.getText()));
-
+                            newTask.setPathImage(newTask.saveImageToExternalStorage(getContext()));
 
                             boolean result =  allTasks.add(newTask);
 
                             {
                                 Log.d(TAG, "new Task: " + newTask.toString());
                                 Log.d(TAG, "add new task result: " + result);
-
-                                /**
-                                for (OwnTask task: allTasks)
-                                {
-                                    if (BuildConfig.DEBUG) {
-                                        Log.d(TAG, task.toString());
-                                    }
-                                }
-                                 **/
                             }
 
                             instantiateTaskList();
                 {
 
                     //save image to external storage and save path
-                    String path = saveReceivedImage(task.getImage(), task.getId());
+                    String path = task.saveImageToExternalStorage(getContext());
                     task.setPathImage(path);
 
                     if (BuildConfig.DEBUG) {
         }
     }
 
-    private String saveReceivedImage(Bitmap bitmap, String imageName){
-
-        File path = null;
-
-        try {
-            path = new File(getContext().getFilesDir(), "meinWald" + File.separator + "Images");
-            if(!path.exists()){
-                path.mkdirs();
-            }
-
-            if (BuildConfig.DEBUG) {
-                Log.d(TAG, "Image file path: " + path);
-            }
-
-            File outFile = new File(path, imageName + ".jpeg");
-            if (!outFile.exists())
-            {
-                FileOutputStream outputStream = new FileOutputStream(outFile);
-                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
-                outputStream.close();
-            }
-
-        } catch (FileNotFoundException e) {
-            Log.e(TAG, "Saving received message failed with", e);
-        } catch (IOException e) {
-            Log.e(TAG, "Saving received message failed with", e);
-        }
-
-        return path.toString();
-    }
-
     /**
      * Reads tasks saved in preferences as jsonStrings
      *
     public void instantiateTaskList()
     {
         final TaskAdapter adapter = new TaskAdapter(getActivity().getApplicationContext(),allTasks);
+
+        adapter.registerDataSetObserver(new DataSetObserver() {
+            @Override
+            public void onChanged() {
+                super.onChanged();
+
+                if (BuildConfig.DEBUG)
+                {
+                    Log.d(TAG, "onChanged");
+                }
+
+                if (BuildConfig.DEBUG)
+                {
+                    Log.d(TAG, "dataset size: " + taskList.getAdapter().getCount());
+                }
+
+                if (taskList.getAdapter().getCount() > 0)
+                {
+                    allTasks = new ArrayList<>();
+
+                    for (int i = 0; i < taskList.getAdapter().getCount(); i++)
+                    {
+                        allTasks.add((OwnTask) taskList.getAdapter().getItem(i));
+                    }
+                }
+            }
+        });
         taskList.setAdapter(adapter);
 
         //initialise onClickListeners
         {
             Bitmap photo = (Bitmap) data.getExtras().get("data");
             newTask.setImage(photo);
-            newTask.setPathImage(saveReceivedImage(photo,newTask.getId()));
 
             if (imageToAdd != null && photo != null)
             {

Code Android/meinWald/app/src/main/res/layout/area_element.xml

         android:focusable="false"
         android:textColor="@android:color/primary_text_light"
         android:textSize="22sp"
+        android:textStyle="bold"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
         <TextView
             android:id="@+id/areaInfoNotice"
             android:layout_width="0dp"
-            android:layout_height="wrap_content"
+            android:layout_height="0dp"
             android:layout_gravity="left"
             android:clickable="false"
+            android:duplicateParentState="true"
             android:focusable="false"
             android:focusableInTouchMode="false"
             android:textColor="@android:color/primary_text_light"
             android:textSize="12sp"
             android:visibility="visible"
-            app:layout_constraintEnd_toStartOf="@+id/taskIcon"
+            app:layout_constraintBottom_toTopOf="@+id/areaInfoArea"
+            app:layout_constraintEnd_toStartOf="@+id/areaIcon"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toTopOf="parent"
-            android:duplicateParentState="true"/>
+            app:layout_constraintTop_toTopOf="parent" />
+
+        <TextView
+            android:id="@+id/areaInfoAreatv"
+            android:layout_width="0dp"
+            android:layout_height="20dp"
+            android:layout_gravity="left"
+            android:layout_marginBottom="5dp"
+            android:clickable="false"
+            android:duplicateParentState="true"
+            android:focusable="false"
+            android:focusableInTouchMode="false"
+            android:text="Fläche:"
+            android:textColor="@android:color/primary_text_light"
+            android:textSize="14sp"
+            android:visibility="visible"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintStart_toStartOf="parent" />
+
+        <TextView
+            android:id="@+id/areaInfoArea"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:layout_gravity="left"
+            android:layout_marginStart="5dp"
+            android:layout_marginLeft="5dp"
+            android:layout_marginBottom="5dp"
+            android:clickable="false"
+            android:duplicateParentState="true"
+            android:focusable="false"
+            android:focusableInTouchMode="false"
+            android:textColor="@android:color/primary_text_light"
+            android:textSize="14sp"
+            android:visibility="visible"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toStartOf="@+id/areaIcon"
+            app:layout_constraintStart_toEndOf="@+id/areaInfoAreatv"
+            app:layout_constraintTop_toTopOf="@+id/areaInfoAreatv" />
 
     </androidx.constraintlayout.widget.ConstraintLayout>
 

Code Android/meinWald/app/src/main/res/layout/area_input.xml

 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/layout_area_root"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
         android:id="@+id/areaTitle"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="5dp"
         android:text="Grundstück"
-        android:textAppearance="?android:attr/textAppearanceLarge" />
+        android:textAppearance="?android:attr/textAppearanceLarge"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
 
     <EditText
         android:id="@+id/areaTitleUserInput"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:hint="Titel eingeben!">
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:hint="Titel eingeben!"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/areaTitle">
 
         <requestFocus />
 
         android:id="@+id/areaManagementNotice"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="15dp"
         android:text="Beschreibung"
-        android:textAppearance="?android:attr/textAppearanceLarge" />
+        android:textAppearance="?android:attr/textAppearanceLarge"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/areaTitleUserInput" />
 
     <EditText
         android:id="@+id/areaManagementNoticeUserInput"
         android:layout_width="match_parent"
         android:layout_height="150dp"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:cursorVisible="true"
         android:hint="Beschreibung eingeben!"
-        android:isScrollContainer="true">
-        <requestFocus />
+        android:isScrollContainer="true"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/areaManagementNotice">
+
     </EditText>
 
     <Button
         android:id="@+id/areaStartTracking"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:text="Grundstücksaufnahme Starten!" />
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="15dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:text="Grundstücksaufnahme Starten!"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/areaManagementNoticeUserInput" />
+
     <Button
         android:id="@+id/areaStopTracking"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="15dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
         android:text="Grundstücksaufnahme Beenden!"
-        android:visibility="invisible"/>
+        android:visibility="invisible"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/areaManagementNoticeUserInput" />
+
+    <Button
+        android:id="@+id/areaAddGPSPoint"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:text="Grenzpunkt hinzufügen"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/areaStartTracking" />
 
-</LinearLayout>
+</androidx.constraintlayout.widget.ConstraintLayout>

Code Android/meinWald/app/src/main/res/layout/area_management.xml

         android:layout_marginStart="5dp"
         android:layout_marginLeft="5dp"
         android:layout_marginTop="15dp"
-        android:text="Bild"
+        android:text="Zuletzt überprüft"
         android:textSize="18sp"
         android:textStyle="bold"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/textView4" />
 
+    <TextView
+        android:id="@+id/textView7"
+        android:layout_width="250dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="15dp"
+        android:text="Bild"
+        android:textSize="18sp"
+        android:textStyle="bold"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/areaManagementLastChecked" />
+
+    <TextView
+        android:id="@+id/areaManagementLastChecked"
+        android:layout_width="0dp"
+        android:layout_height="30dp"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:textSize="12sp"
+        app:layout_constraintEnd_toStartOf="@+id/areaManageNewDate"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView6" />
+
     <ImageView
         android:id="@+id/areaManageImage"
         android:layout_width="match_parent"
         android:layout_marginLeft="5dp"
         android:layout_marginEnd="5dp"
         android:layout_marginRight="5dp"
+        android:src="@android:drawable/ic_menu_gallery"
+        android:visibility="visible"
         app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="1.0"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/textView6"
-        android:src="@android:drawable/ic_menu_gallery"
-        android:visibility="visible"/>
+        app:layout_constraintTop_toBottomOf="@+id/textView7" />
 
     <ImageView
         android:id="@+id/areaManageNewDescription"
         app:layout_constraintEnd_toEndOf="@+id/areaManageGPSPoints"
         android:src="@android:drawable/ic_popup_sync" />
 
+    <ImageView
+        android:id="@+id/areaManageNewDate"
+        android:layout_width="30dp"
+        android:layout_height="30dp"
+        android:src="@android:drawable/ic_popup_sync"
+        android:visibility="visible"
+        app:layout_constraintBottom_toBottomOf="@+id/areaManagementLastChecked"
+        app:layout_constraintEnd_toEndOf="@+id/areaManageGPSPoints"
+        app:tint="#1B5E20" />
+
     <ImageView
         android:id="@+id/areaManageNewImage"
         android:layout_width="30dp"
         android:visibility="visible"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintTop_toTopOf="parent"
-         />
+        />
 </androidx.constraintlayout.widget.ConstraintLayout>

Code Android/meinWald/app/src/main/res/layout/image_large.xml

 
     <ImageView
         android:id="@+id/taskLargeImage"
-        android:layout_width="match_parent"
-        android:layout_height="575dp"
+        android:layout_width="0dp"
+        android:layout_height="500dp"
+        android:layout_marginStart="40dp"
+        android:layout_marginLeft="40dp"
+        android:layout_marginTop="60dp"
+        android:layout_marginEnd="40dp"
+        android:layout_marginRight="40dp"
         android:scaleType="fitXY"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"

Code Android/meinWald/app/src/main/res/layout/task_element.xml

 
     <TextView
         android:id="@+id/taskInfoTitle"
-        android:layout_width="match_parent"
-        android:layout_height="30dp"
+        android:layout_width="0dp"
+        android:layout_height="32dp"
         android:layout_gravity="left"
         android:layout_marginStart="5dp"
         android:layout_marginLeft="5dp"
         android:layout_marginTop="5dp"
-        android:layout_marginEnd="5dp"
-        android:layout_marginRight="5dp"
         android:clickable="false"
         android:focusable="false"
-
         android:textColor="@android:color/primary_text_light"
         android:textSize="22sp"
-        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintEnd_toStartOf="@+id/taskManageTask"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <ImageView
+        android:id="@+id/taskManageTask"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:clickable="true"
+        android:duplicateParentState="true"
+        android:focusable="false"
+        android:focusableInTouchMode="false"
+        android:src="@android:drawable/ic_menu_manage"
+        android:visibility="visible"
+        app:layout_constraintBottom_toTopOf="@+id/areaInfoView"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.0"
+        app:layout_constraintStart_toEndOf="@+id/areaInfoTitle"
+        app:layout_constraintTop_toTopOf="parent" />
+
     <androidx.constraintlayout.widget.ConstraintLayout
         android:id="@+id/taskInfoView"
         android:layout_width="0dp"

Code Android/meinWald/app/src/main/res/layout/task_input.xml

         android:hint="Beschreibung eingeben!"
         android:isScrollContainer="true">
 
-        <requestFocus />
-
     </EditText>
 
     <Button

Code Android/meinWald/app/src/main/res/layout/task_management.xml

+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <TextView
+        android:id="@+id/taskManageTitle"
+        android:layout_width="wrap_content"
+        android:layout_height="50dp"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="5dp"
+        android:text="TextView"
+        android:textSize="36sp"
+        android:textStyle="bold"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <TextView
+        android:id="@+id/textView2"
+        android:layout_width="250dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="5dp"
+        android:text="Beschreibung"
+        android:textSize="18sp"
+        android:textStyle="bold"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/taskManageTitle" />
+
+    <TextView
+        android:id="@+id/taskManageNotice"
+        android:layout_width="0dp"
+        android:layout_height="75dp"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:isScrollContainer="true"
+        android:textSize="12sp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView2" />
+
+    <TextView
+        android:id="@+id/textView4"
+        android:layout_width="250dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="15dp"
+        android:text="Standort"
+        android:textSize="18sp"
+        android:textStyle="bold"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/taskManageNotice" />
+
+    <TextView
+        android:id="@+id/textView6"
+        android:layout_width="250dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginTop="15dp"
+        android:text="Bild"
+        android:textSize="18sp"
+        android:textStyle="bold"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/taskManageGPSPoint" />
+
+    <TextView
+        android:id="@+id/taskManageGPSPoint"
+        android:layout_width="match_parent"
+        android:layout_height="30dp"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:textSize="12sp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView4" />
+
+    <ImageView
+        android:id="@+id/taskManageImage"
+        android:layout_width="match_parent"
+        android:layout_height="200dp"
+        android:layout_marginStart="5dp"
+        android:layout_marginLeft="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView6"
+        android:src="@android:drawable/ic_menu_gallery"
+        android:visibility="visible"/>
+
+    <ImageView
+        android:id="@+id/taskManageNewDescription"
+        android:layout_width="30dp"
+        android:layout_height="30dp"
+        app:tint="#1B5E20"
+        android:visibility="visible"
+        app:layout_constraintBottom_toBottomOf="@+id/taskManageNotice"
+        app:layout_constraintEnd_toEndOf="@+id/taskManageNotice"
+        android:src="@android:drawable/ic_popup_sync" />
+
+    <ImageView
+        android:id="@+id/taskManageNewGPS"
+        android:layout_width="30dp"
+        android:layout_height="30dp"
+        app:tint="#1B5E20"
+        android:visibility="visible"
+        app:layout_constraintBottom_toBottomOf="@+id/taskManageGPSPoint"
+        app:layout_constraintEnd_toEndOf="@+id/taskManageGPSPoint"
+        android:src="@android:drawable/ic_popup_sync" />
+
+    <ImageView
+        android:id="@+id/taskManageNewImage"
+        android:layout_width="30dp"
+        android:layout_height="30dp"
+        app:tint="#1B5E20"
+        android:visibility="visible"
+        app:layout_constraintBottom_toBottomOf="@+id/taskManageImage"
+        app:layout_constraintEnd_toEndOf="@+id/taskManageImage"
+        android:src="@android:drawable/ic_menu_camera" />
+
+    <ImageView
+        android:id="@+id/taskManageDeleteTask"
+        android:layout_width="50dp"
+        android:layout_height="50dp"
+        android:layout_marginTop="5dp"
+        android:layout_marginEnd="5dp"
+        android:layout_marginRight="5dp"
+        android:src="@android:drawable/ic_menu_delete"
+        app:tint="#B71C1C"
+        android:visibility="visible"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

Code Android/meinWald/app/src/main/res/values/colors.xml

 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <color name="colorPrimary">#1B5E20</color>
-    <color name="colorPrimaryDark">#3700B3</color>
+    <color name="colorPrimaryDark">#1B5E20</color>
     <color name="colorAccent">#03DAC5</color>
     <color name="selectionBackground">#c0edc3</color>
+    <color name="colorArea1">#57a639</color>
+    <color name="colorArea2">#819b45</color>
+    <color name="colorArea3">#d3d30c</color>
+    <color name="colorArea4">#df9600</color>
+    <color name="colorArea5">#df3d00</color>
 </resources>