在Android的下一個活動的videoView中傳輸記錄的攝像機視頻（使用Media Recorder）

Question

如何在下一個活動中傳輸攝像機錄制的視頻並在下一個活動的videoView上單擊播放視頻？

相機功能通過使用Media Recorder來執行。

當前嘗試在空對象引用上調用虛擬方法'android.net.Uri android.content.Intent.getData（）'時具有NullPointerException （根據日志）。

如何解決這個問題。 這是我的代碼：

第一次活動

public class AndroidVideoCaptureExample extends Activity {
    private Camera mCamera;
    private CameraPreview mPreview;
    private MediaRecorder mediaRecorder;
    private Button capture, switchCamera;
    private Context myContext;
    private LinearLayout cameraPreview;
    private boolean cameraFront = false;
    String mFileName;
    Intent mediaIntent;
    boolean isPlaying = false;
    Uri url;
    long maxduration = 10000;
    SurfaceHolder holder;
    Uri videoUri;
    private static final int CAMERA_CAPTURE_VIDEO_REQUEST_CODE = 200;

    //  for timer
    private TextView timerValue;
    private long startTime = 0L;
    private Handler customHandler = new Handler();

    long timeInMilliseconds = 0L;
    long timeSwapBuff = 0L;
    long updatedTime = 0L;

    MediaPlayer mediaPlayer;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        myContext = this;
        initialize();
    }

    private int findFrontFacingCamera() {
        int cameraId = -1;
        // Search for the front facing camera
        int numberOfCameras = Camera.getNumberOfCameras();
        for (int i = 0; i < numberOfCameras; i++) {
            CameraInfo info = new CameraInfo();
            Camera.getCameraInfo(i, info);
            if (info.facing == CameraInfo.CAMERA_FACING_FRONT) {
                cameraId = i;
                cameraFront = true;
                break;
            }
        }
        return cameraId;
    }

    private int findBackFacingCamera() {
        int cameraId = -1;
        // Search for the back facing camera
        // get the number of cameras
        int numberOfCameras = Camera.getNumberOfCameras();
        // for every camera check
        for (int i = 0; i < numberOfCameras; i++) {
            CameraInfo info = new CameraInfo();
            Camera.getCameraInfo(i, info);
            if (info.facing == CameraInfo.CAMERA_FACING_BACK) {
                cameraId = i;
                cameraFront = false;
                break;
            }
        }
        return cameraId;
    }

    public void onResume() {
        super.onResume();
        if (!hasCamera(myContext)) {
            Toast toast = Toast.makeText(myContext, "Sorry, your phone does not have a camera!", Toast.LENGTH_LONG);
            toast.show();
            finish();
        }
        if (mCamera == null) {
            // if the front facing camera does not exist
            if (findFrontFacingCamera() < 0) {
                Toast.makeText(this, "No front facing camera found.", Toast.LENGTH_LONG).show();
                switchCamera.setVisibility(View.GONE);
            }
            mCamera = Camera.open(findBackFacingCamera());
            mPreview.refreshCamera(mCamera);
        }
    }

    public void initialize() {
        cameraPreview = (LinearLayout) findViewById(R.id.camera_preview);

        mPreview = new CameraPreview(myContext, mCamera);
        cameraPreview.addView(mPreview);

        capture = (Button) findViewById(R.id.button_capture);
        capture.setOnClickListener(captrureListener);

        switchCamera = (Button) findViewById(R.id.button_ChangeCamera);
        switchCamera.setOnClickListener(switchCameraListener);

        timerValue = (TextView) findViewById(R.id.timer);
    }

    OnClickListener switchCameraListener = new OnClickListener() {
        @Override
        public void onClick(View v) {
            // get the number of cameras
            if (!recording) {
                int camerasNumber = Camera.getNumberOfCameras();
                if (camerasNumber > 1) {
                    // release the old camera instance
                    // switch camera, from the front and the back and vice versa

                    releaseCamera();
                    chooseCamera();
                } else {
                    Toast toast = Toast.makeText(myContext, "Sorry, your phone has only one camera!", Toast.LENGTH_LONG);
                    toast.show();
                }
            }
        }
    };

    public void chooseCamera() {
        // if the camera preview is the front
        if (cameraFront) {
            int cameraId = findBackFacingCamera();
            if (cameraId >= 0) {
                // open the backFacingCamera
                // set a picture callback
                // refresh the preview

                mCamera = Camera.open(cameraId);
                // mPicture = getPictureCallback();
                mPreview.refreshCamera(mCamera);
            }
        } else {
            int cameraId = findFrontFacingCamera();
            if (cameraId >= 0) {
                // open the backFacingCamera
                // set a picture callback
                // refresh the preview

                mCamera = Camera.open(cameraId);
                // mPicture = getPictureCallback();
                mPreview.refreshCamera(mCamera);
            }
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        // when on Pause, release camera in order to be used from other
        // applications
        releaseCamera();
    }

    private boolean hasCamera(Context context) {
        // check if the device has camera
        if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
            return true;
        } else {
            return false;
        }
    }

    boolean recording = false;
    OnClickListener captrureListener = new OnClickListener() {
        @Override
        public void onClick(View v) {
            if (recording) {


                String extension = MimeTypeMap.getFileExtensionFromUrl(mFileName);
                String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
                Intent mediaIntent = new Intent(Intent.ACTION_VIEW);
                mediaIntent.setDataAndType(Uri.parse(mFileName), mimeType);
                startActivityForResult(mediaIntent,CAMERA_CAPTURE_VIDEO_REQUEST_CODE);



                // stop recording and release camera
                mediaRecorder.stop(); // stop the recording
                releaseMediaRecorder(); // release the MediaRecorder object
                Toast.makeText(AndroidVideoCaptureExample.this, "Video captured!", Toast.LENGTH_LONG).show();

                recording = false;


            } else {
                if (!prepareMediaRecorder()) {
                    Toast.makeText(AndroidVideoCaptureExample.this, "Fail in prepareMediaRecorder()!\n - Ended -", Toast.LENGTH_LONG).show();
                    finish();
                }
                // work on UiThread for better performance
                runOnUiThread(new Runnable() {
                    public void run() {
                        // If there are stories, add them to the table

                        try {

                            mediaRecorder.start();


                        } catch (final Exception ex) {
                            // Log.i("---","Exception in thread");
                        }
                    }
                });

                recording = true;
            }
            startTime = SystemClock.uptimeMillis();
            customHandler.postDelayed(updateTimerThread, 0);

        }
    };

    private Runnable updateTimerThread = new Runnable() {

        public void run() {

            timeInMilliseconds = SystemClock.uptimeMillis() - startTime;

            updatedTime = timeSwapBuff + timeInMilliseconds;

            int secs = (int) (updatedTime / 1000);
            int mins = secs / 60;
            secs = secs % 60;
            int milliseconds = (int) (updatedTime % 1000);
            timerValue.setText("" + mins + ":"
                    + String.format("%02d", secs));
            customHandler.postDelayed(this, 0);

        }

    };

    private void releaseCamera() {
        // stop and release camera
        if (mCamera != null) {
            mCamera.release();
            mCamera = null;
        }
    }


    private void releaseMediaRecorder() {
        if (mediaRecorder != null) {
            mediaRecorder.reset(); // clear recorder configuration
            mediaRecorder.release(); // release the recorder object
            mediaRecorder = null;
            mCamera.lock(); // lock camera for later use
        }
    }

    private boolean prepareMediaRecorder() {


        mediaRecorder = new MediaRecorder();

        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
        String i = sdf.format(new Date());
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/audiorecordtest" + i + ".mp4";
        mCamera.unlock();
        mediaRecorder.setCamera(mCamera);

        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
        mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
        mediaRecorder.setMaxDuration((int) maxduration);
        mediaRecorder.setVideoSize(640, 480);
        mediaRecorder.setVideoFrameRate(90);
        mediaRecorder.setVideoEncodingBitRate(3000000);
        //  mediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED()
        mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
        mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
        mediaRecorder.setOutputFile(mFileName);


        try {
            mediaRecorder.prepare();
        } catch (IllegalStateException e) {
            releaseMediaRecorder();
            return false;
        } catch (IOException e) {
            releaseMediaRecorder();
            return false;
        }

        mediaRecorder.setOnInfoListener(new MediaRecorder.OnInfoListener() {
            @Override
            public void onInfo(MediaRecorder mr, int what, int extra) {
                if (what == MediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED) {


                    String extension = MimeTypeMap.getFileExtensionFromUrl(mFileName);
                    String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
                    Intent mediaIntent = new Intent(Intent.ACTION_VIEW);
                    mediaIntent.setDataAndType(Uri.parse(mFileName), mimeType);
                    startActivityForResult(mediaIntent,CAMERA_CAPTURE_VIDEO_REQUEST_CODE);

                    mediaRecorder.stop();
                    if (mediaPlayer.isPlaying()) {
                        mediaPlayer.reset();
                    }
                    mediaPlayer.setDisplay((SurfaceHolder) mPreview);

                    try {
                        mediaPlayer.setDataSource(mFileName);
                        mediaPlayer.prepare();
                    } catch (IllegalArgumentException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IllegalStateException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    mediaPlayer.start();
                }
            }
        });
        return true;
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode==CAMERA_CAPTURE_VIDEO_REQUEST_CODE) {

            videoUri = data.getData();  // get the uri of video from intent
            launchUploadActivity1(true,videoUri);
//  
//          }
        }
    }

    private void launchUploadActivity1(boolean isPlaying, Uri uri) {

        Intent i = new Intent(AndroidVideoCaptureExample.this, SecondLast.class);
//      i.setData(uri);  // set the uri to intent
        i.putExtra("play",videoUri);
        startActivity(i);
    }

}

第二次活動

public class SecondActivity extends Activity {

    MediaPlayer mediaPlayer;
    SurfaceView surfaceView;
    SurfaceHolder surfaceHolder;
    boolean pausing = false;;
     Uri file;
   VideoView video;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

       final Uri videoUri = getIntent().getData();  // do anything from the Uri
        setContentView(R.layout.activity_second_last);

        ImageView buttonPlayVideo = (ImageView) findViewById(R.id.play_button);
        video = (VideoView) findViewById(R.id.video_view);
        ImageView image = (ImageView) findViewById(R.id.image_view);

        Intent i = getIntent();
        file = Uri.parse(i.getExtras().get("play").toString());

        video.setVideoURI(file);
        video.start();





        buttonPlayVideo.setOnClickListener(new Button.OnClickListener(){

            @Override
            public void onClick(View v) {


                Intent i = getIntent();
                file = Uri.parse(i.getExtras().get("play").toString());

                video.setVideoURI(file);
                video.start();


            }});
    }

}

//預覽類

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;
    MediaPlayer mediaPlayer;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mCamera = camera;
        mHolder = getHolder();
        mHolder.addCallback(this);

//      mHolder.setFixedSize(176, 144);

        mediaPlayer = new MediaPlayer();
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }



    public void surfaceCreated(SurfaceHolder holder) {
        try {
            // create the surface and start camera preview
            if (mCamera == null) {
                assert mCamera != null;
                mCamera.setPreviewDisplay(holder);
                mCamera.setDisplayOrientation(90);
                mCamera.startPreview();
            }
        } catch (IOException e) {
            Log.d(VIEW_LOG_TAG, "Error setting camera preview: " + e.getMessage());
        }
    }

    public void refreshCamera(Camera camera) {
        if (mHolder.getSurface() == null) {
            // preview surface does not exist
            return;
        }
        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e) {
            // ignore: tried to stop a non-existent preview
        }
        // set preview size and make any resize, rotate or
        // reformatting changes here
        // start preview with new settings
        setCamera(camera);
        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.setDisplayOrientation(90);


            mCamera.startPreview();
        } catch (Exception e) {
            Log.d(VIEW_LOG_TAG, "Error starting camera preview: " + e.getMessage());
        }
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.
        refreshCamera(mCamera);
    }

    public void setCamera(Camera camera) {
        //method to set a camera instance
        mCamera = camera;
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub
     mCamera.release();
        mHolder.getSurface();

    }
}

我目前的代碼會根據要求重新編碼視頻，並在錄制后立即播放。但是在第二次活動中，它什么也沒做。

Answer 1

在您活動的onActivityResult方法中，獲取uri並將其發送到上載活動：

  @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    if (requestCode==CAMERA_CAPTURE_VIDEO_REQUEST_CODE) {
        launchUploadActivity1(true);
        if (resultCode == RESULT_OK) {

            // video successfully recorded
            // launching upload activity
            Uri videoUri = data.getData();  // get the uri of video from intent
            launchUploadActivity1(true,videoUri);
        }
    }
}

private void launchUploadActivity1(boolean isPlaying, Uri uri) {
    Intent i = new Intent(AndroidVideoCaptureExample.this, SecondLast.class);
    i.setData(uri);  // set the uri to intent
    startActivity(i);
}

在您的SecondLast活動中

protected void onCreate(Bundle b){
  super.onCreate(b);
  Uri videoUri = getIntent().getData();  // do anything from the Uri
}