Using the phone's camera

Question

I m making an app which uses the camera to send data to a surfaceHolder . But when I call the addCallBack() my app crashes. Here is the code :

public class Cam_View extends Activity implements SurfaceHolder.Callback{

private SurfaceView camView;
private SurfaceHolder camHolder;
private boolean previewRunning;

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.camera);

camView = (SurfaceView)findViewById(R.id.sview);
camHolder = camView.getHolder();
camHolder.addCallback(this);
camHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}}

And the unimplemented methods :

 @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width,
    int height) {
if(previewRunning){
    camera.stopPreview();
}
Camera.Parameters camParams = camera.getParameters();
camParams.setPreviewFormat(PixelFormat.JPEG);
camera.setParameters(camParams);
try{
    camera.setPreviewDisplay(holder);
    camera.startPreview();
    previewRunning=true;
}catch(IOException e){
    e.printStackTrace();
}
 }


 public void surfaceCreated(SurfaceHolder holder) {
try{
    camera=Camera.open();
}catch(Exception e){
    e.printStackTrace();
    Toast.makeText(getApplicationContext(),"Error",Toast.LENGTH_LONG).show();
    finish();
}
 }

  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {
camera.stopPreview();
camera.release();
camera=null;
  }

Why does the app crash when i call
camHolder.addCallback(this); ? Are there any other problems in my code ?

Answer 1

I tried your above code.Its working fine on my device. I was able to launch camera successfully. i dont think their is problem in camHolder.addCallback(this);

problem is in line

camParams.setPreviewFormat(PixelFormat.JPEG);

update it with

Camera.Size size = camParams.getSupportedPreviewSizes().get(0); camParams.setPreviewSize(size.width, size.height);

your code will work.

Also make sure the below things are properly added.

1) sview named SurfaceView exits in your layout

2) Add camera permission - "android.permission.CAMERA"

if problem still occurs, please share logs.