Added Alarm Recording to project but RecyclerView crashed

app/src/main/AndroidManifest.xml

     package="com.example.greenwatch">
 
     <uses-permission android:name="android.permission.INTERNET" />
-    <uses-permission android:name="android.permission.CAMERA"/>
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.READ_MEDIA_AUDIO" />
+    <uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
+    <uses-permission android:name="android.permission.CAMERA" />
 
     <uses-feature android:name="android.hardware.camera"/>
 

app/src/main/java/com/example/greenwatch/AccelerometerActivity.java

 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
 import android.os.Bundle;
+import android.view.SurfaceView;
 import android.view.View;
 import android.widget.Button;
 import android.widget.TextView;
 
     private SensorManager accelerometerManager;
     private Sensor accelerometerSensor;
+    private SurfaceView surfaceView;
     private TextView accelerometerStatusMessage;
     private TextView accelerometerDataTV;
     private TextView accelerometerWarningTV;
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_accelerometer);
 
+        surfaceView = (SurfaceView) findViewById(R.id.surfaceViewAccelerometer);
         accelerometerStatusMessage = (TextView) findViewById(R.id.tvAccelerometerStatusmessage);
         accelerometerDataTV = (TextView) findViewById(R.id.tvAccelerometerData);
         accelerometerWarningTV = (TextView) findViewById(R.id.tvAccelerometerWarning);
         });
 
         mAccelerometerViewModel = new ViewModelProvider(this).get(AccelerometerViewModel.class);
-        mAccelerometerViewModel.init();
+        mAccelerometerViewModel.init(surfaceView.getHolder());
         mAccelerometerViewModel.getConnectedDeviceList().observe(this, new Observer<List<Device>>() {
             @Override
             public void onChanged(List<Device> devices) {
             @Override
             public void onChanged(Boolean aBoolean) {
                 if (aBoolean) {
+                    mAccelerometerViewModel.startAlarmRecording();
                     Toast.makeText(AccelerometerActivity.this, "Start Alarm Recording", Toast.LENGTH_LONG).show();
                 }
                 else {
+                    mAccelerometerViewModel.stopAlarmRecording(AccelerometerActivity.this);
                     Toast.makeText(AccelerometerActivity.this, "Stop Alarm Recording", Toast.LENGTH_LONG).show();
                 }
             }

app/src/main/java/com/example/greenwatch/MainActivity.java

 
 import android.content.Intent;
 import android.os.Bundle;
+import android.view.SurfaceView;
 import android.view.View;
 import android.widget.Button;
 import android.widget.Toast;
     private Button audiodetectionAndAccelerometerButton;
     private Button videodetectionAndAccelerometerButton;
     private Button connectionButton;
+    private SurfaceView surfaceView;
     private MainActivityViewModel mMainActivityViewModel;
 
     @Override
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
 
+        surfaceView = (SurfaceView) findViewById(R.id.surfaceViewMainActivity);
         audiodetectionButton = (Button) findViewById(R.id.audiodetectionButton);
         videodetectionButton = (Button) findViewById(R.id.videodetectionButton);
         accelerometerButton = (Button) findViewById(R.id.accelerometerButton);
         alarmHistoryListRecyclerView.setAdapter(alarmHistoryListAdapter);
 
         mMainActivityViewModel = new ViewModelProvider(this).get(MainActivityViewModel.class);
-        mMainActivityViewModel.init();
+        mMainActivityViewModel.init(surfaceView.getHolder());
         mMainActivityViewModel.accessRequestCamera(this);
+        mMainActivityViewModel.accessRequestAudioRecording(this);
+        mMainActivityViewModel.accessRequestWriteExternalStorage(this);
         mMainActivityViewModel.getConnectedDeviceList().observe(this, new Observer<List<Device>>() {
             @Override
             public void onChanged(List<Device> devices) {
             @Override
             public void onChanged(Boolean aBoolean) {
                 if (aBoolean) {
+                    mMainActivityViewModel.startAlarmRecording();
                     Toast.makeText(MainActivity.this, "Start Alarm Recording", Toast.LENGTH_LONG).show();
                 }
                 else {
+                    mMainActivityViewModel.stopAlarmRecording(MainActivity.this);
                     Toast.makeText(MainActivity.this, "Stop Alarm Recording", Toast.LENGTH_LONG).show();
                 }
             }
         startActivity(intent);
     }
     public void openVideodetectionAndAccelerometerActivity(){
-        Intent intent = new Intent(this, VideodetectionAndAccelerometerActivity.class);
-        startActivity(intent);
+        //Intent intent = new Intent(this, VideodetectionAndAccelerometerActivity.class);
+        //startActivity(intent);
     }
     public void openConnectionActivity(){
         //Intent intent = new Intent(this, ConnectionActivity.class);

app/src/main/java/com/example/greenwatch/VideodetectionActivity.java

 import androidx.recyclerview.widget.RecyclerView;
 
 import android.os.Bundle;
+import android.view.SurfaceView;
 import android.view.View;
 import android.widget.Button;
 import android.widget.Toast;
 public class VideodetectionActivity extends AppCompatActivity {
 
     private Button backToMainActivity;
+    private SurfaceView surfaceView;
     private VideodetectionViewModel mVideoDetectionViewModel;
 
     @Override
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_videodetection);
 
+        surfaceView = (SurfaceView) findViewById(R.id.surfaceViewVideodetection);
         backToMainActivity = (Button) findViewById(R.id.videodetectorBackToMainActivity);
 
         RecyclerView recyclerView = findViewById(R.id.deviceListRecyclerView);
         });
 
         mVideoDetectionViewModel = new ViewModelProvider(this).get(VideodetectionViewModel.class);
-        mVideoDetectionViewModel.init();
+        mVideoDetectionViewModel.init(surfaceView.getHolder());
         mVideoDetectionViewModel.getConnectedDeviceList().observe(this, new Observer<List<Device>>() {
             @Override
             public void onChanged(List<Device> devices) {
             @Override
             public void onChanged(Boolean aBoolean) {
                 if (aBoolean) {
+                    mVideoDetectionViewModel.startAlarmRecording();
                     Toast.makeText(VideodetectionActivity.this, "Start Alarm Recording", Toast.LENGTH_LONG).show();
                 }
                 else {
+                    mVideoDetectionViewModel.stopAlarmRecording(VideodetectionActivity.this);
                     Toast.makeText(VideodetectionActivity.this, "Stop Alarm Recording", Toast.LENGTH_LONG).show();
                 }
             }

app/src/main/java/com/example/greenwatch/VideodetectionAndAccelerometerActivity.java

-package com.example.greenwatch;
+/*package com.example.greenwatch;
 
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.camera.lifecycle.ProcessCameraProvider;
             accelerometerManager.unregisterListener(this, accelerometerSensor);
         }
     }
-}
+}*/

app/src/main/java/com/example/greenwatch/alarmrecorder/AlarmRecorder.java

+package com.example.greenwatch.alarmrecorder;
+
+import android.app.Activity;
+import android.content.Context;
+import android.media.MediaCodec;
+import android.media.MediaExtractor;
+import android.media.MediaFormat;
+import android.media.MediaMuxer;
+import android.media.MediaRecorder;
+import android.os.Environment;
+import android.view.SurfaceHolder;
+import android.widget.Toast;
+
+import com.example.greenwatch.MainActivity;
+import com.example.greenwatch.alarmrecorder.runnables.AudioRecorder;
+import com.example.greenwatch.alarmrecorder.runnables.VideoRecorder;
+import com.example.greenwatch.sensors.AccelerometerSensor;
+import com.example.greenwatch.sensors.CameraSensor;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+public class AlarmRecorder {
+    private static AlarmRecorder alarmRecorderInstance;
+    private boolean isRecording;
+    private String videoPath;
+    private String audioPath;
+    private MediaFormat videoFormat;
+    private MediaFormat audioFormat;
+    private MediaExtractor videoExtractor;
+    private MediaExtractor audioExtractor;
+    private Runnable audioRecorderRunnable;
+    private Runnable videoRecorderRunnable;
+    private SurfaceHolder previewHolder;
+    private MediaRecorder videoRecorder;
+    private MediaRecorder audioRecorder;
+    private Thread videoThread; // Video-Thread als Instanzvariable
+    private Thread audioThread; // Audio-Thread als Instanzvariable
+
+    private AlarmRecorder() {
+        audioRecorder = new MediaRecorder();
+        videoRecorder = new MediaRecorder();
+        videoExtractor = new MediaExtractor();
+        audioExtractor = new MediaExtractor();
+    }
+
+    public static synchronized AlarmRecorder getInstance() {
+        if (alarmRecorderInstance == null){
+            alarmRecorderInstance = new AlarmRecorder();
+        }
+        return alarmRecorderInstance;
+    }
+
+    public void setPreviewHolder(SurfaceHolder previewHolder) {
+        this.previewHolder = previewHolder;
+    }
+
+    public void startRecording() {
+        createStoragePaths(); //Speicherort und -namen für Audio- und Video-Datei
+
+        audioRecorderRunnable = new AudioRecorder(audioRecorder, audioPath);
+        videoRecorderRunnable = new VideoRecorder(videoRecorder, videoPath, previewHolder);
+        audioThread = new Thread(audioRecorderRunnable);
+        videoThread = new Thread(videoRecorderRunnable);
+
+        //Threads starten
+        videoThread.start();
+        audioThread.start();
+    }
+
+    public void stopRecording(Context context) {
+        isRecording = false;
+        try {
+            stopVideoRecording();
+            stopAudioRecording();
+
+            Toast.makeText(context, "Video- und Audioaufzeichnung beendet", Toast.LENGTH_SHORT).show();
+
+            waitTillThreadsStopped();
+            File videoFile = new File(videoPath); //Speichere das aufgenommene Video
+            File audioFile = new File(audioPath); //Speichere die aufgenommene Audio
+
+            if (videoFile.exists() && audioFile.exists()) {
+                //Wenn Video- und Audioaufzeichnung gestoppt und abgespeichert sind, beginne mit dem Mergeprozess der beiden
+                mergeVideoWithAudio();
+                Toast.makeText(context, "Video und Audio erfolgreich zusammengeführt", Toast.LENGTH_SHORT).show();
+            } else {
+                Toast.makeText(context, "Dateien wurden nicht gefunden!", Toast.LENGTH_SHORT).show();
+            }
+        } catch (RuntimeException stopException) {
+            stopException.printStackTrace();
+        }
+    }
+
+    private void createStoragePaths(){
+        //Pfade zum Zwischenspeichern der aufgenommenen Audio und Video-Datei
+        isRecording = true;
+        String externalStorageDirectory = Environment.getExternalStorageDirectory().getAbsolutePath();
+        String dcimDirectory = externalStorageDirectory + "/DCIM";
+        videoPath = dcimDirectory + "/video.mp4";
+        audioPath = dcimDirectory + "/audio.mp3";
+    }
+
+    private void stopVideoRecording(){
+        if (videoRecorder != null) {
+            videoRecorder.stop();
+            videoRecorder.release();
+            videoRecorder = null;
+        }
+    }
+
+    private void stopAudioRecording(){
+        if (audioRecorder != null) {
+            audioRecorder.stop();
+            audioRecorder.release();
+            audioRecorder = null;
+        }
+    }
+
+    private void waitTillThreadsStopped(){
+        try {
+            videoThread.join();
+            audioThread.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void mergeVideoWithAudio() {
+        try {
+            setVideoExtractorDataSource(); //extrahieren der Video Datei, die zuvor zwischengespeichert wurde
+            setAudioExtractorDataSource(); //extrahieren der Audio Datei, die zuvor zwischengespeichert wurde
+
+            //Speicherort der später zusammengeführten Datei
+            String outputFilePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES).getAbsolutePath() + "/merged_video.mp4";
+            //MediaMuxer zum Zusammenführen einer Audio- und einer Videodatei
+            MediaMuxer muxer = new MediaMuxer(outputFilePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
+            int videoTrack = muxer.addTrack(videoFormat);
+            int audioTrack = muxer.addTrack(audioFormat);
+            muxer.start();
+
+            ByteBuffer buffer = ByteBuffer.allocate(1024 * 1024);
+            MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
+
+            videoExtraction(buffer, videoTrack, bufferInfo, muxer);
+            audioExtraction(buffer, audioTrack, bufferInfo, muxer);
+
+            muxer.stop();
+            muxer.release();
+
+            // Löschen der separaten Video- und Audio-Dateien
+            deleteVideoFile();
+            deleteAudioFile();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void setVideoExtractorDataSource() {
+        try {
+            videoExtractor.setDataSource(videoPath);
+            int videoTrackIndex = getTrackIndex(videoExtractor, "video/");
+            if (videoTrackIndex < 0) {
+                // Video-Track nicht gefunden
+                return;
+            }
+            videoExtractor.selectTrack(videoTrackIndex);
+            videoFormat = videoExtractor.getTrackFormat(videoTrackIndex);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void setAudioExtractorDataSource() {
+        try {
+            audioExtractor.setDataSource(audioPath);
+            int audioTrackIndex = getTrackIndex(audioExtractor, "audio/");
+            if (audioTrackIndex < 0) {
+                // Audio-Track nicht gefunden
+                return;
+            }
+            audioExtractor.selectTrack(audioTrackIndex);
+            audioFormat = audioExtractor.getTrackFormat(audioTrackIndex);
+
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private int getTrackIndex(MediaExtractor extractor, String mimeType) {
+        int trackCount = extractor.getTrackCount();
+        for (int i = 0; i < trackCount; i++) {
+            MediaFormat format = extractor.getTrackFormat(i);
+            String trackMimeType = format.getString(MediaFormat.KEY_MIME);
+            if (trackMimeType.startsWith(mimeType)) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private void videoExtraction(ByteBuffer buffer, int videoTrack, MediaCodec.BufferInfo bufferInfo, MediaMuxer muxer) {
+        videoExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
+        while (true) {
+            int sampleSize = videoExtractor.readSampleData(buffer, 0);
+            if (sampleSize < 0) {
+                break;
+            }
+            long presentationTimeUs = videoExtractor.getSampleTime();
+            bufferInfo.offset = 0;
+            bufferInfo.size = sampleSize;
+            bufferInfo.flags = MediaCodec.BUFFER_FLAG_KEY_FRAME;
+            bufferInfo.presentationTimeUs = presentationTimeUs;
+            muxer.writeSampleData(videoTrack, buffer, bufferInfo);
+            videoExtractor.advance();
+        }
+    }
+
+    private void audioExtraction(ByteBuffer buffer, int audioTrack, MediaCodec.BufferInfo bufferInfo, MediaMuxer muxer) {
+        audioExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC);
+        while (true) {
+            int sampleSize = audioExtractor.readSampleData(buffer, 0);
+            if (sampleSize < 0) {
+                break;
+            }
+            long presentationTimeUs = audioExtractor.getSampleTime();
+            bufferInfo.offset = 0;
+            bufferInfo.size = sampleSize;
+            bufferInfo.flags = 0; // or MediaCodec.BUFFER_FLAG_KEY_FRAME
+            bufferInfo.presentationTimeUs = presentationTimeUs;
+            muxer.writeSampleData(audioTrack, buffer, bufferInfo);
+            audioExtractor.advance();
+        }
+    }
+
+
+    private void deleteVideoFile(){
+        File videoFile = new File(videoPath);
+        if (videoFile.exists()) {
+            videoFile.delete();
+        }
+    }
+
+    private void deleteAudioFile(){
+        File audioFile = new File(audioPath);
+        if (audioFile.exists()) {
+            audioFile.delete();
+        }
+    }
+}

app/src/main/java/com/example/greenwatch/alarmrecorder/runnables/AudioRecorder.java

+package com.example.greenwatch.alarmrecorder.runnables;
+
+import android.media.MediaRecorder;
+import android.widget.Toast;
+
+import com.example.greenwatch.MainActivity;
+
+import java.io.IOException;
+
+public class AudioRecorder implements Runnable {
+
+    private final MediaRecorder audioRecorder;
+    private final String audioPath;
+    public AudioRecorder(MediaRecorder audioRecorder, String audioPath) {
+        this.audioRecorder = audioRecorder;
+        this.audioPath = audioPath;
+    }
+    @Override
+    public void run() {
+        audioRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
+        audioRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
+        audioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
+        audioRecorder.setOutputFile(audioPath);
+
+        try {
+            audioRecorder.prepare();
+            audioRecorder.start();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+}

app/src/main/java/com/example/greenwatch/alarmrecorder/runnables/VideoRecorder.java

+package com.example.greenwatch.alarmrecorder.runnables;
+
+import android.media.MediaRecorder;
+import android.view.SurfaceHolder;
+
+import com.example.greenwatch.viewmodels.ViewModelInterface;
+
+import java.io.IOException;
+
+public class VideoRecorder implements Runnable{
+    private final MediaRecorder videoRecorder;
+    private final String videoPath;
+    private SurfaceHolder previewHolder;
+
+    public VideoRecorder(MediaRecorder videoRecorder, String videoPath, SurfaceHolder previewHolder) {
+        this.videoRecorder = videoRecorder;
+        this.videoPath = videoPath;
+        this.previewHolder = previewHolder;
+    }
+    @Override
+    public void run() {
+        videoRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
+        videoRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
+        videoRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);
+        videoRecorder.setOutputFile(videoPath);
+        videoRecorder.setOrientationHint(90);
+        //todo find solution for videoView
+        videoRecorder.setPreviewDisplay(previewHolder.getSurface());
+
+        try {
+            videoRecorder.prepare();
+            videoRecorder.start();
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

app/src/main/java/com/example/greenwatch/viewmodels/AccelerometerViewModel.java

 package com.example.greenwatch.viewmodels;
 
+import android.content.Context;
+import android.view.SurfaceHolder;
+
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.ViewModel;
 
+import com.example.greenwatch.alarmrecorder.AlarmRecorder;
 import com.example.greenwatch.models.Device;
 import com.example.greenwatch.repositories.DeviceRepository;
 import com.example.greenwatch.sensors.AccelerometerSensor;
     private MutableLiveData<List<Device>> mAlarmHistoryList;
     private MutableLiveData<Boolean> mStartAlarmRecording;
     private AccelerometerSensor mAccelerometerSensor;
+    private AlarmRecorder mAlarmRecorder;
     private DeviceRepository mDeviceRepository;
 
     @Override
-    public void init() {
+    public void init(SurfaceHolder previewHolder) {
         if (mDeviceRepository == null) {
             mDeviceRepository = DeviceRepository.getInstance();
         }
         if (mAccelerometerSensor == null) {
             mAccelerometerSensor = AccelerometerSensor.getInstance();
         }
+        if (mAlarmRecorder == null) {
+            mAlarmRecorder = AlarmRecorder.getInstance();
+        }
         if (mDeviceList == null) {
             mDeviceList = mDeviceRepository.getConnectedDeviceList();
         }
         if (mAccelerometerAlarmDetected == null) {
             mAccelerometerAlarmDetected = mAccelerometerSensor.getAccelerometerAlarmDetected();
         }
+        setAlarmRecordingPreviewHolder(previewHolder);
     }
 
     public void addValueToGesamtBE(float newValue) {
     public String getSystemTimeStamp() {
         return mDeviceRepository.getSystemTimeStamp();
     }
+
+    @Override
+    public void startAlarmRecording() {
+        mAlarmRecorder.startRecording();
+    }
+
+    @Override
+    public void stopAlarmRecording(Context context) {
+        mAlarmRecorder.stopRecording(context);
+    }
+
+    @Override
+    public void setAlarmRecordingPreviewHolder(SurfaceHolder previewHolder) {
+        mAlarmRecorder.setPreviewHolder(previewHolder);
+    }
 }

app/src/main/java/com/example/greenwatch/viewmodels/MainActivityViewModel.java

 package com.example.greenwatch.viewmodels;
 
+import android.Manifest;
 import android.app.Activity;
 import android.content.Context;
 import android.content.pm.PackageManager;
+import android.view.SurfaceHolder;
 
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.ViewModel;
 
+import com.example.greenwatch.alarmrecorder.AlarmRecorder;
 import com.example.greenwatch.communication.WiFiCommunication;
 import com.example.greenwatch.models.Device;
 import com.example.greenwatch.repositories.DeviceRepository;
     private MutableLiveData<List<Device>> mAlarmHistoryList;
     private MutableLiveData<Boolean> mStartAlarmRecording;
     private DeviceRepository mDeviceRepository;
+    private AlarmRecorder mAlarmRecorder;
     private static final int RIGHTS_REQUEST_CAMERA = 10;
+    private static final int REQUEST_PERMISSION = 200;
 
     @Override
-    public void init() {
+    public void init(SurfaceHolder previewHolder) {
         WiFiCommunication mWiFiCommunication;
         if(mDeviceList != null) {
             return;
         }
+        if (mAlarmRecorder == null) {
+            mAlarmRecorder = AlarmRecorder.getInstance();
+        }
         //todo: check if WiFi instanz can be hold only by the repository
         mDeviceRepository = DeviceRepository.getInstance();
         mWiFiCommunication = WiFiCommunication.getInstance();
         mDeviceRepository.setWiFiCommunication(mWiFiCommunication);
         mWiFiCommunication.setDeviceRepository(mDeviceRepository);
-        mDeviceRepository.createNewDevice(mDeviceRepository.getSystemTimeStamp(), mDeviceRepository.getLocalDeviceUUID(), false, "No Sensor selected", 0);
+        //mDeviceRepository.createNewDevice(mDeviceRepository.getSystemTimeStamp(), mDeviceRepository.getLocalDeviceUUID(), false, "No Sensor selected", 0);
         mDeviceList = mDeviceRepository.getConnectedDeviceList();
         mAlarmHistoryList = mDeviceRepository.getAlarmHistoryDeviceList();
         mStartAlarmRecording = mDeviceRepository.getStartAlarmRecording();
+        setAlarmRecordingPreviewHolder(previewHolder);
     }
 
     public boolean isCameraAccessAllowed(Context context) {
         ActivityCompat.requestPermissions(activity, new String[]{android.Manifest.permission.CAMERA}, RIGHTS_REQUEST_CAMERA);
     }
 
+    public boolean isAudioRecordingAccessAllowed(Context context) {
+        return ContextCompat.checkSelfPermission(context, Manifest.permission.RECORD_AUDIO) == PackageManager.PERMISSION_GRANTED;
+    }
+
+    public void accessRequestAudioRecording(Activity activity) {
+        ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.RECORD_AUDIO}, REQUEST_PERMISSION);
+    }
+
+    public boolean isWriteExternalStorageAccessAllowed(Context context) {
+        return ContextCompat.checkSelfPermission(context, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;
+    }
+
+    public void accessRequestWriteExternalStorage(Activity activity) {
+        ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_PERMISSION);
+    }
+
     @Override
     public LiveData<List<Device>> getConnectedDeviceList() {
         return mDeviceList;
     public String getSystemTimeStamp() {
         return null;
     }
+
+    @Override
+    public void startAlarmRecording() {
+        mAlarmRecorder.startRecording();
+    }
+
+    @Override
+    public void stopAlarmRecording(Context context) {
+        mAlarmRecorder.stopRecording(context);
+    }
+
+    @Override
+    public void setAlarmRecordingPreviewHolder(SurfaceHolder previewHolder) {
+        mAlarmRecorder.setPreviewHolder(previewHolder);
+    }
 }

app/src/main/java/com/example/greenwatch/viewmodels/VideodetectionAndAccelerometerViewModel.java

 
 import java.util.List;
 
-public class VideodetectionAndAccelerometerViewModel extends ViewModel implements ViewModelInterface{
+/*public class VideodetectionAndAccelerometerViewModel extends ViewModel implements ViewModelInterface{
     private MutableLiveData<List<Device>> mDeviceList;
     private MutableLiveData<Boolean> mAccelerometerAlarmDetected;
     private MutableLiveData<Boolean> mVideoAlarmDetected;
     public String getSystemTimeStamp() {
         return mDeviceRepository.getSystemTimeStamp();
     }
-}
+}*/

app/src/main/java/com/example/greenwatch/viewmodels/VideodetectionViewModel.java

 package com.example.greenwatch.viewmodels;
 
 import android.content.Context;
+import android.view.SurfaceHolder;
 
 import androidx.camera.lifecycle.ProcessCameraProvider;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.ViewModel;
 
+import com.example.greenwatch.alarmrecorder.AlarmRecorder;
 import com.example.greenwatch.models.Device;
 import com.example.greenwatch.repositories.DeviceRepository;
 import com.example.greenwatch.sensors.CameraSensor;
     private MutableLiveData<List<Device>> mAlarmHistoryList;
     private MutableLiveData<Boolean> mStartAlarmRecording;
     private DeviceRepository mDeviceRepository;
+    private AlarmRecorder mAlarmRecorder;
     private CameraSensor mCameraSensor;
 
 
     }
 
     @Override
-    public void init() {
+    public void init(SurfaceHolder previewHolder) {
         if (mDeviceRepository == null) {
             mDeviceRepository = DeviceRepository.getInstance();
         }
         if (mCameraSensor == null) {
             mCameraSensor = CameraSensor.getInstance();
         }
+        if (mAlarmRecorder == null) {
+            mAlarmRecorder = AlarmRecorder.getInstance();
+        }
         if (mDeviceList == null) {
             mDeviceList = mDeviceRepository.getConnectedDeviceList();
         }
         if (mVideoAlarmDetected == null) {
             mVideoAlarmDetected = mCameraSensor.getVideoAlarmDetectedValue();
         }
+        setAlarmRecordingPreviewHolder(previewHolder);
     }
 
     public void bindImageAnalysis(ProcessCameraProvider cameraProvider, LifecycleOwner lifecycleOwner, Context context) {
     public String getSystemTimeStamp() {
         return mDeviceRepository.getSystemTimeStamp();
     }
+
+    @Override
+    public void startAlarmRecording() {
+        mAlarmRecorder.startRecording();
+    }
+
+    @Override
+    public void stopAlarmRecording(Context context) {
+        mAlarmRecorder.stopRecording(context);
+    }
+
+    @Override
+    public void setAlarmRecordingPreviewHolder(SurfaceHolder previewHolder) {
+        mAlarmRecorder.setPreviewHolder(previewHolder);
+    }
 }

app/src/main/java/com/example/greenwatch/viewmodels/ViewModelInterface.java

 package com.example.greenwatch.viewmodels;
 
+import android.content.Context;
+import android.view.SurfaceHolder;
+
 import androidx.lifecycle.LiveData;
 
 import com.example.greenwatch.models.Device;
 import java.util.List;
 
 public interface ViewModelInterface {
-    void init();
+    void init(SurfaceHolder previewHolder);
     LiveData<List<Device>> getConnectedDeviceList();
     LiveData<List<Device>> getAlarmHistoryList();
     LiveData<Boolean> getStartAlarmRecording();
     int getSensorMassage(String deviceID);
     String getLocalDeviceUUID();
     String getSystemTimeStamp();
+    void startAlarmRecording();
+    void stopAlarmRecording(Context context);
+    void setAlarmRecordingPreviewHolder(SurfaceHolder previewHolder);
 }

app/src/main/res/layout/activity_accelerometer.xml

     android:padding="10dp"
     tools:context=".AccelerometerActivity">
 
+    <SurfaceView
+        android:id="@+id/surfaceViewAccelerometer"
+        android:layout_width="1dp"
+        android:layout_height="1dp"
+        android:visibility="visible">
+    </SurfaceView>
+
     <TextView
         android:id="@+id/tvAccelerometerStatusmessage"
         android:layout_width="match_parent"

app/src/main/res/layout/activity_main.xml

         android:id="@+id/alarmHistoryListRecyclerView"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:layout_weight="3"
+        android:layout_weight="4"
         tools:listitem="@layout/alarm_history_item">
     </androidx.recyclerview.widget.RecyclerView>
 
         android:id="@+id/deviceListRecyclerView"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:layout_weight="3"
+        android:layout_weight="4"
         tools:listitem="@layout/device_item">
     </androidx.recyclerview.widget.RecyclerView>
+
+    <SurfaceView
+        android:id="@+id/surfaceViewMainActivity"
+        android:layout_width="1dp"
+        android:layout_height="1dp">
+    </SurfaceView>
     
     <LinearLayout
         android:layout_width="match_parent"

app/src/main/res/layout/activity_videodetection.xml

     android:padding="10dp"
     tools:context=".VideodetectionActivity">
 
+    <SurfaceView
+        android:id="@+id/surfaceViewVideodetection"
+        android:layout_width="1dp"
+        android:layout_height="1dp"
+        android:visibility="visible">
+    </SurfaceView>
+
     <TextView
         android:id="@+id/tvVideodetectionStatusmessage"
         android:layout_width="match_parent"