我已经编写了这段代码来在屏幕的 surfaceview 上打开前置摄像头，但是当你点击按钮时我想用前置摄像头录制视频。

此代码崩溃。我为相机使用了两个不同的变量，但我没有发现我的错误 :(.. 我遵循了谷歌指南。

public class MainActivity extends Activity {
    public static final int MEDIA_TYPE_VIDEO = 2;

    private Camera mCamera;
    private CameraPreview mPreview;
    public static final int MEDIA_TYPE_IMAGE = 1;
    protected static final String TAG = null;

    private MediaRecorder mMediaRecorder; 
    private Camera mCamerafront;
    private boolean isRecording = false;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Button captureButton = (Button) findViewById(id.button_capture);
        mCamera = getCameraInstance();

        // Create our Preview view and set it as the content of our activity.
        mPreview = new CameraPreview(this, mCamera);
        FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
        preview.addView(mPreview);




        // Add a listener to the Capture button
        Button captureButton = (Button) findViewById(id.button_capture);
        captureButton.setOnClickListener(
                new View.OnClickListener() {

                    public void onClick(View v) {
                        if (isRecording) {
                            // stop recording and release camera
                            mMediaRecorder.stop();  // stop the recording
                            releaseMediaRecorder(); // release the MediaRecorder object
                            mCamerafront.lock();         // take camera access back from MediaRecorder

                            // inform the user that recording has stopped
                            //setCaptureButtonText("Capture");
                            isRecording = false;
                        } else {
                            // initialize video camera
                            if (prepareVideoRecorder()) {
                                // Camera is available and unlocked, MediaRecorder is prepared,
                                // now you can start recording
                                mMediaRecorder.start();

                                // inform the user that recording has started
                                //setCaptureButtonText("Stop");
                                isRecording = true;
                            } else {
                                // prepare didn't work, release the camera
                                releaseMediaRecorder();
                                // inform user
                            }
                        }
                    }
                }
                );

        /*  captureButton.setOnClickListener(
                new View.OnClickListener() {
                    public void onClick(View v) {
                        // get an image from the camera
                        mCamera.takePicture(null, null, mPicture);
                    }
                }
            );*/
    }



    //*PARTE registrazione 
    private boolean prepareVideoRecorder(){
        int cameraCount = Camera.getNumberOfCameras()-1;
        mCamerafront=Camera.open(cameraCount); 


        mMediaRecorder = new MediaRecorder();
        mCamerafront.unlock();
        mMediaRecorder.setCamera(mCamerafront);
        mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
        mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mMediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));
        mMediaRecorder.setOutputFile(getOutputMediaFile(MEDIA_TYPE_VIDEO).toString());

        try {
            mMediaRecorder.prepare();
        } catch (IllegalStateException e) {
            Log.d(TAG, "IllegalStateException preparing MediaRecorder: " + e.getMessage());
            // releaseMediaRecorder();
            return false;
        } catch (IOException e) {
            Log.d(TAG, "IOException preparing MediaRecorder: " + e.getMessage());
            //releaseMediaRecorder();
            return false;
        }
        return true;

    }

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

    /** Check if this device has a camera */
    private boolean checkCameraHardware(Context context) {
        if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
            // this device has a camera
            return true;
        } else {
            // no camera on this device
            return false;
        }
    }


    /** A safe way to get an instance of the Camera object. */
    public static Camera getCameraInstance(){
        Camera c = null;
        try {
            c = Camera.open(); // attempt to get a Camera instance
        }
        catch (Exception e){
            // Camera is not available (in use or does not exist)
        }
        return c; // returns null if camera is unavailable
    }


    /** A basic Camera preview class */
    public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
        private final String TAG = null;
        private SurfaceHolder mHolder;
        private Camera mCamera;

        public CameraPreview(Context context, Camera camera) {
            super(context);
            mCamera = camera;

            // Install a SurfaceHolder.Callback so we get notified when the
            // underlying surface is created and destroyed.
            mHolder = getHolder();
            mHolder.addCallback(this);
            // deprecated setting, but required on Android versions prior to 3.0
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }

        public void surfaceCreated(SurfaceHolder holder) {
            // The Surface has been created, now tell the camera where to draw the preview.
            try {
                mCamera.setPreviewDisplay(holder);
                mCamera.startPreview();
            } catch (IOException e) {
                Log.d(TAG, "Error setting camera preview: " + e.getMessage());
            }
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
            // empty. Take care of releasing the Camera preview in your activity.
        }

        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.

            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
            try {
                mCamera.setPreviewDisplay(mHolder);
                mCamera.startPreview();

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

    @Override
    protected void onPause() {
        super.onPause();
        // if you are using MediaRecorder, release it first
        releaseCamera();              // release the camera immediately on pause event
    }



    private void releaseCamera(){
        if (mCamera != null){
            mCamera.release();        // release the camera for other applications
            mCamera = null;
        }
    }







    private PictureCallback mPicture = new PictureCallback() {


        public void onPictureTaken(byte[] data, Camera camera) {

            File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);


            try {
                FileOutputStream fos = new FileOutputStream(pictureFile);
                fos.write(data);
                fos.close();
            } catch (FileNotFoundException e) {
                Log.d(TAG, "File not found: " + e.getMessage());
            } catch (IOException e) {
                Log.d(TAG, "Error accessing file: " + e.getMessage());
            }
        }
    };


    private static Uri getOutputMediaFileUri(int type){
        return Uri.fromFile(getOutputMediaFile(type));
    }

    /** Create a File for saving an image or video */
    private static File getOutputMediaFile(int type){
        // To be safe, you should check that the SDCard is mounted
        // using Environment.getExternalStorageState() before doing this.

        File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES), "MyCameraApp");
        // This location works best if you want the created images to be shared
        // between applications and persist after your app has been uninstalled.

        // Create the storage directory if it does not exist
        if (! mediaStorageDir.exists()){
            if (! mediaStorageDir.mkdirs()){
                Log.d("MyCameraApp", "failed to create directory");
                return null;
            }
        }

        // Create a media file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        File mediaFile;
        if (type == MEDIA_TYPE_IMAGE){
            mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                    "IMG_"+ timeStamp + ".jpg");
        } else if(type == MEDIA_TYPE_VIDEO) {
            mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                    "VID_"+ timeStamp + ".mp4");
        } else {
            return null;
        }

        return mediaFile;
    }







    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

最佳答案

您需要在 AndroidManifest.xml 文件中添加以下权限:

<uses-permission android:name="android.permission.RECORD_AUDIO" />

关于android - 在 SurfaceView 上打开默认摄像头并使用前置摄像头进行录制，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13122966/