Implementierung einer Runnable Class mit Preview in einer SurfaceView in der MainActivity

app/src/main/AndroidManifest.xml

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.example.greenwatch">
 
+    <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
-    <uses-permission android:name="android.permission.READ_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" />
 

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

+package com.example.greenwatch;
+
+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 java.io.File;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+public class AlarmRecorder {
+    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 MediaRecorder videoRecorder;
+    private MediaRecorder audioRecorder;
+    private SurfaceHolder previewHolder;
+    private Thread videoThread; // Video-Thread als Instanzvariable
+    private Thread audioThread; // Audio-Thread als Instanzvariable
+
+    public AlarmRecorder(SurfaceHolder previewHolder) {
+        audioRecorder = new MediaRecorder();
+        videoRecorder = new MediaRecorder();
+        videoExtractor = new MediaExtractor();
+        audioExtractor = new MediaExtractor();
+        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() {
+        try {
+            stopVideoRecording();
+            stopAudioRecording();
+
+            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();
+            } else { }
+        } catch (RuntimeException stopException) {
+            stopException.printStackTrace();
+        }
+    }
+
+    private void createStoragePaths(){
+        //Pfade zum Zwischenspeichern der aufgenommenen Audio und Video-Datei
+        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/AudioRecorder.java

+package com.example.greenwatch;
+
+import android.media.MediaRecorder;
+
+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/Beschleunigungssensor.java

-package com.example.greenwatch;
-
-public class Beschleunigungssensor {
-}

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

-package com.example.greenwatch;
-
-public class Kamera {
-}

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

 
 import android.Manifest;
 import android.content.pm.PackageManager;
-import android.media.MediaCodec;
-import android.media.MediaExtractor;
-import android.media.MediaFormat;
-import android.media.MediaMuxer;
-import android.media.MediaRecorder;
 import android.os.Bundle;
-import android.os.Environment;
+import android.view.SurfaceView;
 import android.view.View;
 import android.widget.Button;
 import android.widget.Toast;
-import android.widget.VideoView;
 
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 
-import java.io.File;
-import java.io.IOException;
-import java.nio.ByteBuffer;
-
 public class MainActivity extends AppCompatActivity {
 
-    private boolean alarm_on = false; //ToDo diese Variable durch die Alarm-Variable=true setzen und nicht über einen Button
-    private boolean alarm_off = false; //ToDo diese Variable durch die Alarm-Variable=false setzen und nicht über einen Button
+    private boolean isRecording = false;
     private static final int REQUEST_PERMISSION = 200;
     private Button button;
-    private VideoView videoView;
-    private MediaRecorder mediaRecorder;
-    private MediaRecorder audioRecorder;
-    private MediaFormat videoFormat;
-    private MediaFormat audioFormat;
-    private MediaExtractor videoExtractor;
-    private MediaExtractor audioExtractor;
-    private String videoPath;
-    private String audioPath;
-    private boolean isRecording = false;
-
-    private Thread videoThread; // Video-Thread als Instanzvariable
-    private Thread audioThread; // Audio-Thread als Instanzvariable
-
+    private SurfaceView surfaceView;
+    private AlarmRecorder alarmRecorder;
     private static final int REQUEST_PERMISSIONS = 123;
 
     @Override
         setContentView(R.layout.activity_main);
 
         button = findViewById(R.id.button);
-        videoView = findViewById(R.id.videoView);
+        surfaceView = findViewById(R.id.surfaceView);
+        alarmRecorder = new AlarmRecorder(surfaceView.getHolder());
 
         button.setOnClickListener(new View.OnClickListener() {
             @Override
                         ActivityCompat.requestPermissions(MainActivity.this,
                                 new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.RECORD_AUDIO},
                                 REQUEST_PERMISSION);
-
-
                     } else {
-                        alarm_on = true;
-                        onAlarmStateChanged();
+                        isRecording = true;
+                        alarmRecorder.startRecording();
                     }
                 } else {
-                    alarm_off = true;
-                    onAlarmStateChanged();
+                    isRecording = false;
+                    alarmRecorder.stopRecording();
                 }
             }
         });
     @Override
     public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
         super.onRequestPermissionsResult(requestCode, permissions, grantResults);
-        if (requestCode == REQUEST_PERMISSION) {
-            boolean allPermissionsGranted = true;
-            for (int grantResult : grantResults) {
-                if (grantResult != PackageManager.PERMISSION_GRANTED) {
-                    allPermissionsGranted = false;
-                    break;
-                }
-            }
-            if (allPermissionsGranted) {
-                startRecording(); // Starte die Aufnahme, da alle Berechtigungen erteilt wurden
+        if (requestCode == REQUEST_PERMISSIONS) {
+            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+                // Berechtigungen wurden gewährt
+                Toast.makeText(this, "Berechtigungen gewährt", Toast.LENGTH_SHORT).show();
+                isRecording = true;
+                alarmRecorder.startRecording();
             } else {
-                Toast.makeText(this, "Berechtigung verweigert.", Toast.LENGTH_SHORT).show();
-            }
-        }
-    }
-
-
-    public void onAlarmStateChanged() {
-        runOnUiThread(new Runnable() {
-            @Override
-            public void run() {
-                if (alarm_on) {
-                    alarm_on = false; //Variable zurücksetzen
-                    startRecording();
-                } else if (alarm_off) {
-                    alarm_off = false; //Variable zurücksetzen
-                    stopRecording();
-                }
-            }
-        });
-    }
-
-    private void cache(){
-        //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 VideoThread(){
-        videoThread = new Thread(new Runnable() {
-            @Override
-            public void run() {
-                mediaRecorder = new MediaRecorder();
-                mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
-                mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
-                mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);
-                mediaRecorder.setOutputFile(videoPath);
-                mediaRecorder.setOrientationHint(90);
-                mediaRecorder.setPreviewDisplay(videoView.getHolder().getSurface());
-
-                try {
-                    mediaRecorder.prepare();
-                    mediaRecorder.start();
-                    /*runOnUiThread(new Runnable() {
-                        @Override
-                        public void run() {
-                            Toast.makeText(MainActivity.this, "Videoaufzeichnung gestartet", Toast.LENGTH_SHORT).show();
-                        }
-                    });*/
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-            }
-        });
-    }
-
-    public class AudioTask implements Runnable {
-
-        @Override
-        public void run() {
-            audioRecorder = new MediaRecorder();
-            audioRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
-            audioRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
-            audioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
-            audioRecorder.setOutputFile(audioPath);
-
-            try {
-                audioRecorder.prepare();
-                audioRecorder.start();
-                runOnUiThread(new Runnable() {
-                    @Override
-                    public void run() {
-                        Toast.makeText(MainActivity.this, "Audioaufzeichnung gestartet", Toast.LENGTH_SHORT).show();
-                    }
-                });
-            } catch (IOException e) {
-                e.printStackTrace();
-            }
-        }
-    }
-
-    /*private void AudioThread(){
-        audioThread = new Thread(new Runnable() {
-            @Override
-            public void run() {
-                audioRecorder = new MediaRecorder();
-                audioRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
-                audioRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
-                audioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
-                audioRecorder.setOutputFile(audioPath);
-
-                try {
-                    audioRecorder.prepare();
-                    audioRecorder.start();
-                    runOnUiThread(new Runnable() {
-                        @Override
-                        public void run() {
-                            Toast.makeText(MainActivity.this, "Audioaufzeichnung gestartet", Toast.LENGTH_SHORT).show();
-                        }
-                    });
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-            }
-        });
-    }*/
-
-    private void startRecording() {
-        cache(); //Speicherort und -namen für Audio- und Video-Datei
-
-        VideoThread(); //Videoaufzeichnungs-Thread anlegen
-        Runnable audiotask = new AudioTask();
-        audioThread = new Thread(audiotask);
-        //AudioThread(); //Audioaufzeichnungs-Thread anlegen
-
-        //Threads starten
-        videoThread.start();
-        audioThread.start();
-    }
-
-    private void stopVideoRecording(){
-        if (mediaRecorder != null) {
-            mediaRecorder.stop();
-            mediaRecorder.release();
-            mediaRecorder = 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 stopRecording() {
-        isRecording = false;
-        try {
-            stopVideoRecording();
-            stopAudioRecording();
-
-            runOnUiThread(new Runnable() {
-                @Override
-                public void run() {
-                    Toast.makeText(MainActivity.this, "Video- und Audioaufzeichnung beendet", Toast.LENGTH_SHORT).show();
-                }
-            });
-
-            waitTillThreadsStopped();
-            boolean test = videoThread.isAlive();
-            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
-                Toast.makeText(MainActivity.this, String.valueOf(test) , Toast.LENGTH_SHORT).show();
-                mergeVideoWithAudio();
-            } else {
-                Toast.makeText(MainActivity.this, "Dateien wurden nicht gefunden!", Toast.LENGTH_SHORT).show();
-            }
-        } catch (RuntimeException stopException) {
-            stopException.printStackTrace();
-        }
-    }
-
-    private void newMediaExtractor() {
-        videoExtractor = new MediaExtractor();
-        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 newAudioExtractor() {
-        audioExtractor = new MediaExtractor();
-        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 void mediaExtraction(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 mergeVideoWithAudio() {
-        try {
-            newMediaExtractor(); //extrahieren der Video Datei, die zuvor zwischengespeichert wurde
-            newAudioExtractor(); //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();
-
-            mediaExtraction(buffer, videoTrack, bufferInfo, muxer);
-            audioExtraction(buffer, audioTrack, bufferInfo, muxer);
-
-            muxer.stop();
-            muxer.release();
-
-            runOnUiThread(new Runnable() {
-                @Override
-                public void run() {
-                    Toast.makeText(MainActivity.this, "Video und Audio erfolgreich zusammengeführt", Toast.LENGTH_SHORT).show();
-                }
-            });
-
-            // Löschen der separaten Video- und Audio-Dateien
-            deleteVideoFile();
-            deleteAudioFile();
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
-    }
-
-    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();
-        }
-    }
-
-    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;
+                // Berechtigungen wurden nicht gewährt
+                Toast.makeText(this, "Berechtigungen nicht gewährt", Toast.LENGTH_SHORT).show();
             }
         }
-        return -1;
     }
 }

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

-package com.example.greenwatch;
-
-public class Mikrofon {
-}

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

+package com.example.greenwatch;
+
+import android.media.MediaRecorder;
+import android.view.SurfaceHolder;
+
+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);
+        videoRecorder.setPreviewDisplay(previewHolder.getSurface());
+
+        try {
+            videoRecorder.prepare();
+            videoRecorder.start();
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}
+

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

     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
-    <VideoView
-        android:id="@+id/videoView"
+    <SurfaceView
+        android:id="@+id/surfaceView"
         android:layout_width="1dp"
         android:layout_height="1dp"
         android:visibility="visible"