Question

我想使用切换相机功能。目前我开发了一款相机对象，可以很好地用于后置摄像头，但不能用于前置摄像头。我无法找到前后摄像头之间切换的解决方案。这是我的代码..！

 public class MyCamera extends Activity implements SurfaceHolder.Callback,
    Camera.ShutterCallback, Camera.PictureCallback {
    Camera mCamera;
    SurfaceView mPreview;
    String filePath;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.camera_preview);
        mPreview = (SurfaceView) findViewById(R.id.preview);
        mPreview.getHolder().addCallback(this);
        mPreview.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        mCamera = Camera.open();
    }

    @Override
    public void onPause() {
        super.onPause();
        mCamera.stopPreview();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mCamera.release();
        Log.d("CAMERA", "Destroy");
    }

    public void onCancelClick(View v) {
        finish();
    }

    public void onSnapClick(View v) {
        mCamera.takePicture(this, null, null, this);
    }

    @Override
    public void onShutter() {
        Toast.makeText(this, "Click!", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        FileOutputStream fos = null;
        try {
            filePath = "/sdcard/test.jpg";
            fos = new FileOutputStream(filePath);
            fos.write(data);
            fos.close();
            // Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
        } catch (IOException e) {
            e.printStackTrace();
            Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
        } finally {
            Intent i = getIntent();
            i.putExtra("Path", filePath);
            setResult(RESULT_OK, i);
            finish();
        }
        camera.startPreview();
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        Camera.CameraInfo info = new Camera.CameraInfo();
        Camera.getCameraInfo(Camera.CameraInfo.CAMERA_FACING_FRONT, info);
        int rotation = this.getWindowManager().getDefaultDisplay()
                .getRotation();
        int degrees = 0;
        switch (rotation) {
        case Surface.ROTATION_0:
            degrees = 0;
            break; // Natural orientation
        case Surface.ROTATION_90:
            degrees = 90;
            break; // Landscape left
        case Surface.ROTATION_180:
            degrees = 180;
            break;// Upside down
        case Surface.ROTATION_270:
            degrees = 270;
            break;// Landscape right
        }
        int rotate = (info.orientation - degrees + 360) % 360;
        Camera.Parameters params = mCamera.getParameters();
        params.setRotation(rotate);
        mCamera.setParameters(params);
        mCamera.setDisplayOrientation(90);
        mCamera.startPreview();
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            mCamera.setPreviewDisplay(mPreview.getHolder());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        Log.i("PREVIEW", "surfaceDestroyed");
    }
}

Answer 1

尝试以下代码

mCamera= Camera.open(cameraId);

0表示CAMERA_FACING_BACK

1 for CAMERA_FACING_FRONT

参考Camera.open(int)

Camera Info Constants

Answer 2

这是我的相机切换前/后的最终代码，它正在为我工作..

public class MyCamera extends Activity implements SurfaceHolder.Callback, Camera.ShutterCallback, Camera.PictureCallback {

    Camera mCamera;
    SurfaceView mPreview;
    String filePath ;
    int currentCameraId = 0;
    @SuppressWarnings("deprecation")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.camera_preview);
        mPreview = (SurfaceView)findViewById(R.id.preview);
        mPreview.getHolder().addCallback(this);
        mPreview.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        mCamera = Camera.open(currentCameraId);
    }

    @Override
    public void onPause() {
        super.onPause();
        mCamera.stopPreview();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mCamera.release();
        Log.d("CAMERA","Destroy");
    }

    public void onCancelClick(View v) {

        mCamera.stopPreview();
        mCamera.release();
        if(currentCameraId == Camera.CameraInfo.CAMERA_FACING_BACK){
            currentCameraId = Camera.CameraInfo.CAMERA_FACING_FRONT;
        }
        else {
            currentCameraId = Camera.CameraInfo.CAMERA_FACING_BACK;
        }
        mCamera = Camera.open(currentCameraId);
        Camera.CameraInfo info = new Camera.CameraInfo();
        Camera.getCameraInfo(Camera.CameraInfo.CAMERA_FACING_FRONT, info);
        int rotation = this.getWindowManager().getDefaultDisplay().getRotation();
        int degrees = 0;
        switch (rotation) {
            case Surface.ROTATION_0: degrees = 0; break; //Natural orientation
                case Surface.ROTATION_90: degrees = 90; break; //Landscape left
                case Surface.ROTATION_180: degrees = 180; break;//Upside down
                case Surface.ROTATION_270: degrees = 270; break;//Landscape right
            }
        int rotate = (info.orientation - degrees + 360) % 360;

        //STEP #2: Set the 'rotation' parameter
        Camera.Parameters params = mCamera.getParameters();
        params.setRotation(rotate); 
          try {
            mCamera.setPreviewDisplay(mPreview.getHolder());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        mCamera.setParameters(params);
        mCamera.setDisplayOrientation(90);
        mCamera.startPreview();
    }

    public void onSnapClick(View v) {
        mCamera.takePicture(this, null, null, this);
    }

    @Override
    public void onShutter() {
        Toast.makeText(this, "Click!", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        //Here, we chose internal storage
         FileOutputStream fos = null;
         try {
             filePath = "/sdcard/test.jpg";
             fos = new FileOutputStream(
                     filePath);
             fos.write(data);
             fos.close();
             //Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
         } catch (FileNotFoundException e) {
             e.printStackTrace();
             Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
         } catch (IOException e) {
             e.printStackTrace();
             Log.d("Log", "onPictureTaken - wrote bytes: " + data.length);
         } finally {
             Intent i = getIntent();
             i.putExtra("Path",filePath);
             setResult(RESULT_OK, i);
             finish();
         }
        camera.startPreview();
    }
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        Camera.CameraInfo info = new Camera.CameraInfo();
        Camera.getCameraInfo(Camera.CameraInfo.CAMERA_FACING_BACK, info);
        int rotation = this.getWindowManager().getDefaultDisplay().getRotation();
        int degrees = 0;
        switch (rotation) {
            case Surface.ROTATION_0: degrees = 0; break; //Natural orientation
                case Surface.ROTATION_90: degrees = 90; break; //Landscape left
                case Surface.ROTATION_180: degrees = 180; break;//Upside down
                case Surface.ROTATION_270: degrees = 270; break;//Landscape right
            }
        int rotate = (info.orientation - degrees + 360) % 360;

        //STEP #2: Set the 'rotation' parameter
        Camera.Parameters params = mCamera.getParameters();
        params.setRotation(rotate); 
        mCamera.setParameters(params);
        mCamera.setDisplayOrientation(90);
        mCamera.startPreview();
    }
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            mCamera.setPreviewDisplay(mPreview.getHolder());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        Log.i("PREVIEW","surfaceDestroyed");
    }
}

Answer 3

尝试使用此：

.setFacing(CameraSource.CAMERA_FACING_FRONT)

切换到前置摄像头和后置摄像头Android SurfaceView

3 个答案: