切换回/前置摄像头 [英] switch back/front camera on fly

问题描述

如果我只使用 CAMERA_FACING_BACK 或 CAMERA_FACING_FRONT ，所有工作正常。

If I use only CAMERA_FACING_BACK or CAMERA_FACING_FRONT all works fine.

我从 CAMERA_FACING_BACK 切换到 CAMERA_FACING_FRONT 时遇到问题。

I have trouble with switch from CAMERA_FACING_BACK to CAMERA_FACING_FRONT.

我的代码片段：

public class PhotoCameraActivity extends Activity implements OnClickListener {
private SurfaceView cameraView;
private Button turnButton;
private Camera camera = null;
private Callback listener;
private static int camId = Camera.CameraInfo.CAMERA_FACING_BACK;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.photo_camera_main);
    prepareActivity();
}

private void prepareActivity() {
    cameraView = (SurfaceView) findViewById(R.id.photo_camera_surface_view);

    turnButton = (ImageButton) findViewById(R.id.turn_button);
    turnButton.setOnClickListener(this);
}

@Override
public void onClick(View v) {
    if (v.equals(turnButton)) {
        if (Camera.getNumberOfCameras() > 1 && camId < Camera.getNumberOfCameras() - 1) {
            startCamera(camId + 1);
        } else {
            startCamera(Camera.CameraInfo.CAMERA_FACING_BACK);
        }
    } 
}

@Override
protected void onResume() {
    startCamera(camId);
    super.onResume();
}

@Override
protected void onPause() {
    stopCamera();
    super.onPause();
}

private void startCamera(int cameraId) {
    if (camera != null) {
        stopCamera();
    }       
    holder = cameraView.getHolder();
    listener = new Callback() {

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                camera.setPreviewDisplay(holder);
                camera.startPreview();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int           width, int height) {}
    };
    holder.addCallback(listener);


    camId = cameraId;
    camera = Camera.open(cameraId);
    Camera.Parameters params = camera.getParameters();
    if (cameraId == Camera.CameraInfo.CAMERA_FACING_BACK) {
        params.setPreviewSize(1280, 800);
    } else {
        params.setPreviewSize(640, 480);
    }
    camera.setParameters(params);

}

private void stopCamera(){
    System.out.println("stopCamera method");
    if (camera != null){
        camera.stopPreview();
        camera.setPreviewCallback(null);
        camera.release();
        camera = null;
        holder.removeCallback(listener);
        holder = null;
    }
}

}

推荐答案

我重新启动activity with cameraId = 2，这是工作。

I restart Activity with cameraId = 2 and this is working.

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