method called after release() exception unable to resume with android camera

Question

While developing a camera app I\'ve encountered an exception that only happened when I switch to other app (onPause() for my app).

01-15 17:22:1         


        

Answer 1

To Resume correctly, you need to do this:

@Override
public void onResume() {
    super.onResume();  

    // Get the Camera instance as the activity achieves full user focus
    if (mCamera == null) {
        initializeCamera(); // Local method to handle camera initialization
    }
}



protected void initializeCamera(){
    // Get an instance of Camera Object
    mCamera = getCameraInstance();

   // create a basic camera preview class that can be included in a View layout.
    mPreview=new CameraPreview(this,mCamera);

    //add your preview class to the FrameLayout element.
    preview.addView(mPreview);

   //Trigger capturing an image by calling the Camera.takePicture() method.
    captureButton.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // get an image from the camera
                    mCamera.takePicture(null, null, mPicture);
                }
            }
        );
}

And also just to remind that in oncreate() do nothing except defining FrameLayout preview and Button captureButton.

Answer 2

I've got the same problem. mCamera.setPreviewCallback(null); didn't help. In my activity I've added this to releaseCamera:

mPreview.getHolder().removeCallback(mPreview);

and it works now.

Answer 3

@Override public void surfaceDestroyed(SurfaceHolder surfaceHolder) {

    this.getHolder().removeCallback(this);
    mCamera.stopPreview();
    mCamera.release();
    mCamera = null;
  Log.e("surfaceDestroyed", "surfaceDestroyed");

}

And re initialize the camera in on Resume function.

Answer 4

I have put

mPreview.getHolder().removeCallback(mPreview);  

between.

mCamera.setPreviewCallback(null);

and

mCamera.release();

and it worked for me.

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

                this.saveTextEdits();
                try {
                    mCamera.stopPreview();
                    mCamera.setPreviewCallback(null);
                    **mPreview.getHolder().removeCallback(mPreview);**
                    mCamera.release();
                    mCamera = null;
                }catch (Exception e){

                }
            }

Answer 5

@ookami.kb solution worked for me too, as well as @srunni commented.

public void onPause() {
    super.onPause();

    if (mCamera != null) {
        mCamera.setPreviewCallback(null);
        mPreview.getHolder().removeCallback(mPreview);
        mCamera.release();
    }
}

I removed onDestroy method too.

Answer 6

Adding to okambi's answer.

This is the function messing everything up when you resume:

 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());
        }
    }

The try{} is not catching the exception being thrown. Namely that mCamera doesn't exist, and then when it tries to call setPreviewDisplay(holder), there is a crash.

So by removing the callback, this surfaceCreated doesn't get called and avoids the crash.

This is VERY POORLY DOCUMENTED by Google.