Merge branch 'test' of siebenhaarmi76624/MDT5_1_Ueberwachungssystem_G1 into ms

app/build.gradle

@@ -36,13 +36,4 @@ dependencies {
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'androidx.test.ext:junit:1.1.5'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
-
-    // Required for CameraX
-    def camerax_version = "1.2.3"
-    implementation "androidx.camera:camera-core:${camerax_version}"
-    implementation "androidx.camera:camera-camera2:${camerax_version}"
-    implementation "androidx.camera:camera-lifecycle:${camerax_version}"
-    implementation "androidx.camera:camera-video:${camerax_version}"
-    implementation "androidx.camera:camera-view:${camerax_version}"
-    implementation "androidx.camera:camera-extensions:${camerax_version}"
 }

app/src/main/AndroidManifest.xml

@@ -2,11 +2,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
 
-    <uses-feature android:name="android.hardware.camera"/>
-
-    <uses-permission android:name="android.permission.CAMERA" />
-    <uses-permission android:name="android.permission.RECORD_AUDIO" />
-
     <application
         android:allowBackup="true"
         android:dataExtractionRules="@xml/data_extraction_rules"

app/src/main/java/com/example/ueberwachungssystem/AudioRecorder.java

@@ -1,76 +0,0 @@
-package com.example.ueberwachungssystem;
-
-import android.content.Context;
-import android.hardware.Camera;
-import android.media.CamcorderProfile;
-import android.media.MediaPlayer;
-import android.media.MediaRecorder;
-import android.util.Log;
-import android.view.SurfaceView;
-import android.widget.VideoView;
-
-import java.io.File;
-import java.io.IOException;
-
-public class AudioRecorder {
-    private final Context context;
-    private Camera camera;
-    private MediaRecorder mediaRecorder = null;
-    private SurfaceView surfaceView;
-
-    public AudioRecorder (Context context) {
-        this.context = context;
-        this.surfaceView = new SurfaceView(context);
-    }
-
-
-    public void startRecording() {
-
-        mediaRecorder = new MediaRecorder();
-
-        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
-        mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
-        mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
-        mediaRecorder.setOutputFile(context.getFilesDir() + "/audio.mp3");
-
-
-        try {
-            mediaRecorder.prepare();
-            mediaRecorder.start();
-        } catch (IOException e) {
-            Log.e("audioRecorder", "prepare() failed");
-        }
-    }
-
-    public void stopRecording() {
-        if (mediaRecorder != null) {
-            try {
-                mediaRecorder.stop();
-                mediaRecorder.release();
-                mediaRecorder = null;
-            } catch (RuntimeException e) {
-                // RuntimeException may be thrown if the MediaRecorder is in an invalid state
-                e.printStackTrace();
-            }
-        }
-    }
-
-    public void playAudio() {
-        MediaPlayer mp = new MediaPlayer();
-        try {
-            mp.setDataSource(context.getFilesDir() + "/audio.mp3");
-            mp.prepare();
-            mp.start();
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-    }
-
-
-    public void deleteRecording(){
-        File file = new File(context.getFilesDir() + "/audio.mp3");
-        if (file.exists()) {
-            file.delete();
-        }
-    }
-}

app/src/main/java/com/example/ueberwachungssystem/Detection/DetectionReport.java

@@ -1,36 +0,0 @@
-package com.example.ueberwachungssystem.Detection;
-
-import android.util.Log;
-
-import java.util.Calendar;
-
-/** Detection Report Class */
-public class DetectionReport {
-    public String timeStamp;
-    public String detectionType;
-    public float detectedValue;
-    public String detectorID;
-
-    public DetectionReport(String detectorID, String detectionType, float detectedAmplitude) {
-        this.timeStamp = String.valueOf(Calendar.getInstance().getTime());
-        this.detectionType = detectionType;
-        this.detectedValue = detectedAmplitude;
-        this.detectorID = detectorID;
-    }
-
-
-    /** Get Detection Report in String format */
-    public String toString() {
-        String time = "Time: " + "[" + this.timeStamp + "]";
-        String type = "Type: " + "[" + this.detectionType + "]";
-        String value = "Value: " + "[" + this.detectedValue + "]";
-        String id = "ID: " + "[" + this.detectorID + "]";
-
-        return String.join("\t", time, type, value, id);
-    }
-
-    /** Debug Report */
-    public void log(String tag) {
-        Log.d(tag, this.toString());
-    }
-}

app/src/main/java/com/example/ueberwachungssystem/Detection/Detector.java

@@ -1,38 +0,0 @@
-package com.example.ueberwachungssystem.Detection;
-
-import androidx.annotation.NonNull;
-
-
-abstract public class Detector {
-    private OnDetectionListener listener;
-
-    /** Constructor - takes context of current activity */
-    public Detector() {}
-
-
-    /** On Detection Listener - runs when violation is reported */
-    public interface OnDetectionListener {
-        void onDetection(@NonNull DetectionReport detectionReport);
-    }
-    public void setOnDetectionListener(@NonNull OnDetectionListener listener) {
-        this.listener = listener;
-    }
-
-
-    /** Triggers onDetectionListener - call this to trigger violation/alarm */
-    public void reportViolation(String detectorID, String detectionType, float amplitude) {
-        if (listener != null) {
-            DetectionReport detectionReport = new DetectionReport(detectorID, detectionType, amplitude);
-            listener.onDetection(detectionReport);
-        } else {
-            throw new IllegalStateException("No listener set for violation reporting");
-        }
-    }
-
-
-    /** Starts Detection (abstract method: needs to be overridden in child class) */
-    public abstract void startDetection();
-
-    /** Stops Detection (abstract method: needs to be overridden in child class) */
-    public abstract void stopDetection();
-}

app/src/main/java/com/example/ueberwachungssystem/Detection/VideoDetector.java

@@ -1,257 +0,0 @@
-package com.example.ueberwachungssystem.Detection;
-
-import android.Manifest;
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.content.pm.PackageManager;
-import android.graphics.ImageFormat;
-import android.media.Image;
-import android.util.Size;
-import android.view.Surface;
-import android.widget.Toast;
-import android.widget.VideoView;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.camera.core.CameraSelector;
-import androidx.camera.core.ExperimentalGetImage;
-import androidx.camera.core.ImageAnalysis;
-import androidx.camera.core.Preview;
-import androidx.camera.core.VideoCapture;
-import androidx.camera.lifecycle.ProcessCameraProvider;
-import androidx.camera.view.PreviewView;
-import androidx.core.app.ActivityCompat;
-import androidx.core.content.ContextCompat;
-import androidx.lifecycle.LifecycleOwner;
-
-import com.google.common.util.concurrent.ListenableFuture;
-
-import java.io.File;
-import java.nio.ByteBuffer;
-import java.util.concurrent.ExecutionException;
-
-
-/**
- * Video Detector inherits some methods from abstract Detector class (more info there)
- *
- *
- * USE FROM MAIN ACTIVITY:
- *
- * VideoDetector vd = new VideoDetector(this);
- * vd.setPreview(previewView);  //THIS IS OPTIONAL!
- * vd.setOnDetectionListener(new Detector.OnDetectionListener{...});
- * vd.startDetection();
- * vd.stopDetection
- *
- * */
-
-
-@ExperimentalGetImage
-public class VideoDetector extends Detector {
-
-    // Calling Activity
-    private final Context context;
-    // Camera Provider
-    private ProcessCameraProvider cameraProvider;
-    private Boolean isDetectionRunning = false;
-    // Preview Camera Image
-    private PreviewView previewView = null;
-    private VideoCapture videoCapture = null;
-    // Detect Violation
-    private static final float PIXEL_THRESHOLD = 30f;  // Luminosity (brightness channel of YUV_420_888)
-    private static final float ALARM_THRESHOLD = 0.2f;   // Percent of pixels changed
-    private ByteBuffer previousBuffer = null;
-
-
-    /**
-     * Constructor
-     * @param context: the context of calling activity (usually "this")
-     * */
-    public VideoDetector(Context context) {
-        super();
-        this.context = context;
-    }
-
-
-    /**
-     *  Starts the Video Detection
-     * */
-    @Override
-    public void startDetection() {
-        if (isDetectionRunning)
-            return;
-        // Request Camera Provider
-        final ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(context);
-        //Check for Camera availability
-        cameraProviderFuture.addListener(() -> {
-            try {
-                cameraProvider = cameraProviderFuture.get();
-                bindAnalysis(cameraProvider);
-                isDetectionRunning = true;
-                previousBuffer = null;
-            } catch (ExecutionException | InterruptedException e) {
-                // No errors need to be handled for this Future. This should never be reached.
-            }
-        }, ContextCompat.getMainExecutor(context));
-    }
-
-
-    /**
-     * Stops the Video Detection
-     * */
-    @Override
-    public void stopDetection() {
-        if (!isDetectionRunning)
-            return;
-        cameraProvider.unbindAll();
-        isDetectionRunning = false;
-    }
-
-
-    /**
-     * Set PreviewView to show video feed while detecting
-     * this is optional and does not need to be called
-     * */
-    public void setPreviewView(PreviewView previewView) {
-        this.previewView = previewView;
-    }
-
-
-    /**
-     * Binds the Luminosity Analyzer (configure and run Analysis)
-     * @param cameraProvider: CameraProvider of Context passed by Constructor
-     * */
-    @SuppressLint("RestrictedApi")
-    private void bindAnalysis(@NonNull ProcessCameraProvider cameraProvider) {
-        // Configure and create Image Analysis
-        ImageAnalysis.Builder builder = new ImageAnalysis.Builder();
-        builder.setTargetResolution(new Size(640, 480));
-        builder.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST);
-        builder.setOutputImageFormat(ImageAnalysis.OUTPUT_IMAGE_FORMAT_YUV_420_888);
-        ImageAnalysis imageAnalysis = builder.build();
-
-        // Set Analyzer
-        imageAnalysis.setAnalyzer(ContextCompat.getMainExecutor(context), imageProxy -> {
-            if (imageProxy.getFormat() == ImageFormat.YUV_420_888) {
-                Image image = imageProxy.getImage();
-                assert image != null;
-
-                // Changed Pixel Detection
-                int pixelChanged = getChangedPixelCount(image);
-                int width = image.getWidth();
-                int height = image.getHeight();
-
-                float percentPixelChanged = (float) 100f * pixelChanged / (width * height);
-
-                if (percentPixelChanged > ALARM_THRESHOLD)
-                    reportViolation("0", "Video", percentPixelChanged);
-            }
-            imageProxy.close();
-        });
-        // Create Preview
-        Preview preview = new Preview.Builder().build();
-        // Specify which Camera to use
-        CameraSelector cameraSelector = new CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build();
-        // Update PreviewView if set
-        if (previewView != null)
-            preview.setSurfaceProvider(previewView.getSurfaceProvider());
-
-        videoCapture = new VideoCapture.Builder()
-                .setVideoFrameRate(30)
-                .setTargetRotation(Surface.ROTATION_0)
-                .build();
-
-
-        cameraProvider.bindToLifecycle((LifecycleOwner) context, cameraSelector, imageAnalysis, videoCapture);
-    }
-
-
-    @SuppressLint("RestrictedApi")
-    public void startRecording() {
-
-        File dir = context.getFilesDir();
-        String filename = "recording";
-        String vidFilePath = dir.getAbsolutePath() + "/" + filename + ".mp4";
-        File vidFile = new File(vidFilePath);
-
-        if (ActivityCompat.checkSelfPermission(context, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
-            // TODO: Consider calling
-            //    ActivityCompat#requestPermissions
-            // here to request the missing permissions, and then overriding
-            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
-            //                                          int[] grantResults)
-            // to handle the case where the user grants the permission. See the documentation
-            // for ActivityCompat#requestPermissions for more details.
-            return;
-        }
-        videoCapture.startRecording(
-                new VideoCapture.OutputFileOptions.Builder(vidFile).build(),
-                context.getMainExecutor(),
-                new VideoCapture.OnVideoSavedCallback() {
-                    @Override
-                    public void onVideoSaved(@NonNull VideoCapture.OutputFileResults outputFileResults) {
-                        Toast.makeText(context, "recording saved", Toast.LENGTH_SHORT).show();
-                    }
-
-                    @Override
-                    public void onError(int videoCaptureError, @NonNull String message, @Nullable Throwable cause) {
-                        Toast.makeText(context, "recording failed", Toast.LENGTH_SHORT).show();
-                    }
-                }
-        );
-    }
-
-    @SuppressLint("RestrictedApi")
-    public void stopRecording(){
-        videoCapture.stopRecording();
-    }
-
-    /**
-     * Calculate Amount of Pixels changed using a threshold
-     * @param image
-     * */
-    private int getChangedPixelCount(Image image) {
-        Image.Plane[] planes = image.getPlanes();
-        ByteBuffer buffer = planes[0].getBuffer();
-
-        if (previousBuffer == null) {
-            previousBuffer = ByteBuffer.allocate(buffer.capacity());
-            buffer.rewind();
-            previousBuffer.put(buffer);
-            previousBuffer.rewind();
-            return 0;
-        }
-
-        int width = image.getWidth();
-        int height = image.getHeight();
-
-        int yRowStride = image.getPlanes()[0].getRowStride();
-        int yPixelStride = image.getPlanes()[0].getPixelStride();
-
-        int changedPixelCount = 0;
-
-        // Count changed pixels
-        for (int y = 0; y < height; ++y) {
-            for (int x = 0; x < width; x++) {
-                int index = (y * yRowStride) + (x * yPixelStride);
-                int luminosity = (buffer.get(index) & 0xff);
-                int previousLuminosity = (previousBuffer.get(index) & 0xff);
-                int diff = Math.abs(luminosity - previousLuminosity);
-                if (diff > PIXEL_THRESHOLD)
-                    changedPixelCount++;
-            }
-        }
-
-        // Reset and copy Byte Buffer
-        buffer.rewind();
-        previousBuffer.rewind();
-        previousBuffer.put(buffer);
-
-        return changedPixelCount;
-    }
-
-    public void playVideo(VideoView videoView) {
-        videoView.setVideoPath(context.getFilesDir() + "/recording.mp4");
-        videoView.start();
-    }
-}

app/src/main/java/com/example/ueberwachungssystem/DetectionRecorder.java

@@ -1,147 +0,0 @@
-package com.example.ueberwachungssystem;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.content.pm.PackageManager;
-import android.media.MediaPlayer;
-import android.view.Surface;
-import android.widget.Toast;
-import android.widget.VideoView;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.camera.core.CameraSelector;
-import androidx.camera.core.Preview;
-import androidx.camera.core.VideoCapture;
-import androidx.camera.lifecycle.ProcessCameraProvider;
-import androidx.camera.view.PreviewView;
-import androidx.core.app.ActivityCompat;
-import androidx.core.content.ContextCompat;
-import androidx.lifecycle.LifecycleOwner;
-
-import com.google.common.util.concurrent.ListenableFuture;
-
-import java.io.File;
-import java.util.concurrent.ExecutionException;
-
-public class DetectionRecorder {
-
-    private final Context context;
-    private ProcessCameraProvider cameraProvider;
-    private VideoCapture videoCapture = null;
-    private PreviewView previewView = null;
-    private boolean isRunning = false;
-    private boolean isVideoPlaying = false;
-
-
-    // Constructor
-    public DetectionRecorder(Context context) {
-        this.context = context;
-    }
-
-
-    public void start() {
-        if (isRunning)
-            return;
-        isRunning = true;
-
-        // Request Camera Provider
-        final ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(context);
-        //Check for Camera availability
-        cameraProviderFuture.addListener(() -> {
-            try {
-                cameraProvider = cameraProviderFuture.get();
-                startCameraX(cameraProvider);
-            } catch (ExecutionException | InterruptedException e) {
-                // No errors need to be handled for this Future. This should never be reached.
-            }
-        }, ContextCompat.getMainExecutor(context));
-    }
-
-
-    @SuppressLint("RestrictedApi")
-    public void stop() {
-        if (!isRunning)
-            return;
-
-        videoCapture.stopRecording();
-        cameraProvider.unbind(videoCapture);
-        isRunning = false;
-    }
-
-    @SuppressLint("RestrictedApi")
-    private void startCameraX(ProcessCameraProvider cameraProvider) {
-        //cameraProvider.unbindAll();
-
-        CameraSelector cameraSelector = new CameraSelector.Builder()
-                .requireLensFacing(CameraSelector.LENS_FACING_BACK)
-                .build();
-
-        // Preview Use Case
-        Preview preview = new Preview.Builder().build();
-        if (previewView != null)
-            preview.setSurfaceProvider(previewView.getSurfaceProvider());
-
-        // Video Capture Use Case
-        videoCapture = new VideoCapture.Builder()
-                .setVideoFrameRate(30)
-                .setTargetRotation(Surface.ROTATION_0)
-                .build();
-
-        cameraProvider.bindToLifecycle((LifecycleOwner) context, cameraSelector, preview, videoCapture);
-
-
-        File dir = context.getFilesDir();
-        String filename = "recording";
-        String vidFilePath = dir.getAbsolutePath() + "/" + filename + ".mp4";
-        File vidFile = new File(vidFilePath);
-
-        if (ActivityCompat.checkSelfPermission(context, android.Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
-            // TODO: Consider calling
-            //    ActivityCompat#requestPermissions
-            // here to request the missing permissions, and then overriding
-            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
-            //                                          int[] grantResults)
-            // to handle the case where the user grants the permission. See the documentation
-            // for ActivityCompat#requestPermissions for more details.
-            return;
-        }
-        videoCapture.startRecording(
-                new VideoCapture.OutputFileOptions.Builder(vidFile).build(),
-                context.getMainExecutor(),
-                new VideoCapture.OnVideoSavedCallback() {
-                    @Override
-                    public void onVideoSaved(@NonNull VideoCapture.OutputFileResults outputFileResults) {
-                        Toast.makeText(context, "recording saved", Toast.LENGTH_SHORT).show();
-                    }
-                    @Override
-                    public void onError(int videoCaptureError, @NonNull String message, @Nullable Throwable cause) {
-                        Toast.makeText(context, "recording failed", Toast.LENGTH_SHORT).show();
-                    }
-                }
-        );
-    }
-
-    /** Set PreviewView to show Image */
-    public void setPreviewView(PreviewView previewView) {
-        this.previewView = previewView;
-    }
-
-    private void playAudio() {
-        MediaPlayer mp = new MediaPlayer();
-        try {
-            mp.setDataSource(context.getFilesDir() + "/audio.gpp");
-            mp.prepare();
-            mp.start();
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-    }
-
-    public void playVideo(VideoView videoView) {
-        if (isVideoPlaying)
-            return;
-        videoView.setVideoPath(context.getFilesDir() + "/recording.mp4");
-        videoView.start();
-    }
-}

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

@@ -1,120 +1,15 @@
 package com.example.ueberwachungssystem;
 
-import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
-import androidx.camera.view.PreviewView;
-import androidx.core.app.ActivityCompat;
-import androidx.core.content.ContextCompat;
-import androidx.camera.core.ExperimentalGetImage;
 
-import android.Manifest;
-import android.content.pm.PackageManager;
 import android.os.Bundle;
-import android.util.Log;
-import android.view.View;
-import android.widget.TextView;
-import android.widget.Toast;
-import android.widget.ToggleButton;
-import android.widget.VideoView;
 
-import com.example.ueberwachungssystem.Detection.DetectionReport;
-import com.example.ueberwachungssystem.Detection.Detector;
-import com.example.ueberwachungssystem.Detection.VideoDetector;
-
-import java.io.File;
-import java.util.Arrays;
-
-@ExperimentalGetImage
 public class MainActivity extends AppCompatActivity {
 
-    private static final int PERMISSION_REQUEST_CODE = 111;
-
-
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
-
-        TextView textView = findViewById(R.id.textView);
-        VideoView videoView = findViewById(R.id.videoView);
-        PreviewView previewView = findViewById(R.id.previewView);
-
-        File directory = getFilesDir();
-
-
-        AudioRecorder ar = new AudioRecorder(this);
-
-
-        //DetectionRecorder detectionRecorder = new DetectionRecorder(this);
-        //detectionRecorder.setPreviewView(previewView);
-
-        ToggleButton toggleButton = findViewById(R.id.previewButton);
-        ToggleButton toggleButton2 = findViewById(R.id.toggleButton2);
-
-        toggleButton.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View v) {
-                getRecordVideoAccess();
-                File[] files = directory.listFiles();
-                textView.setText(Arrays.toString(files));
-
-                if (isRecordVideoAllowed() && toggleButton.isChecked())
-                {
-                    ar.startRecording();
-                    //vd.startRecording();
-                    //vd.playVideo(videoView);
-                    //detectionRecorder.playVideo(videoView);
-                    //detectionRecorder.start();
-                }
-                else {
-                    ar.stopRecording();
-                    //vd.stopRecording();
-
-                    //detectionRecorder.stop();
-                }
-            }
-        });
-
-        toggleButton2.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View v) {
-                if (toggleButton.isChecked())
-                {
-                    ar.playAudio();
-                }
-                else {
-                    ar.deleteRecording();
-                }
-            }
-        });
-    }
-
-    private boolean isRecordVideoAllowed() {
-        return ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED &&
-                ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) == PackageManager.PERMISSION_GRANTED;
-    }
-
-    private void getRecordVideoAccess() {
-        if (!isRecordVideoAllowed()) {
-            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.RECORD_AUDIO}, PERMISSION_REQUEST_CODE);
-        }
-    }
-
-
-    @Override
-    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
-        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
-
-        if (requestCode == PERMISSION_REQUEST_CODE && grantResults.length > 0) {
-
-            boolean cameraRights = grantResults[0] == PackageManager.PERMISSION_GRANTED;
-            boolean recordAudioRights = grantResults[1] == PackageManager.PERMISSION_GRANTED;
-
-            if (cameraRights && recordAudioRights) {
-                Toast.makeText(this, "permissions granted", Toast.LENGTH_LONG).show();
-            } else {
-                Toast.makeText(this, "permissions denied", Toast.LENGTH_LONG).show();
-            }
-        }
+        //
     }
 }

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

@@ -1,48 +1,18 @@
 <?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:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:layout_gravity="center"
-    android:gravity="center"
-    android:orientation="vertical"
     tools:context=".MainActivity">
 
     <TextView
-        android:id="@+id/textView"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text=""
-        android:textSize="20dp"
+        android:text="Hello World!"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
-
-    <ToggleButton
-        android:id="@+id/previewButton"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:text="ToggleButton" />
-
-
-    <ToggleButton
-        android:id="@+id/toggleButton2"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:text="ToggleButton" />
-
-    <androidx.camera.view.PreviewView
-        android:id="@+id/previewView"
-        android:layout_width="match_parent"
-        android:layout_height="200dp" />
-
-    <VideoView
-        android:id="@+id/videoView"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content" />
-
-
-</LinearLayout>
+</androidx.constraintlayout.widget.ConstraintLayout>