Question

I have two button’s in the main menu. I invoking the camera when I press the 1st button. Here I didn’t get any issue. Camera working properly. After taking the picture, I come back in to main menu and again I press the 1st button. Here I got the issue. Camera invoking properly. But I got ANR error (Reason: keyDispatchingTimedOut) while i’m taking the picture. How to resolve this issue?

Edit::

I’m using following code,

Button Listener,

Button imageButton = (Button) findViewById(R.id.button1);
imageButton.setOnClickListener(new  View.OnClickListener() {

    public void onClick(View arg0) {
    Intent intent = new Intent();
    intent.setClass(activity, ImageActivity.class);
    startActivity(intent);
    }
});

ImageActivity.java

public class ImageActivity extends Activity implements SurfaceHolder.Callback {
    private Camera camera = null;
    private SurfaceHolder surfaceHolder = null;
    private boolean previewRunning = false;
    private Button btnDone, btnCapture, btnRetake;
    private Bitmap mBitmap;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFormat(PixelFormat.TRANSLUCENT);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.surface_screen);
        SurfaceView surfaceView = (SurfaceView) findViewById(R.id.camerapreview);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        surfaceHolder.setFixedSize(getWindow().getWindowManager()
                .getDefaultDisplay().getWidth(), getWindow().getWindowManager()
                .getDefaultDisplay().getHeight());
        LayoutInflater  controlInflater = LayoutInflater.from(getBaseContext());

        final View viewControl = controlInflater.inflate(R.layout.control, null);
        LayoutParams layoutParamsControl = new LayoutParams(
                LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
        activity.addContentView(viewControl, layoutParamsControl);

        btnCapture = (Button) findViewById(R.id.takepicture);

        btnDone = (Button) findViewById(R.id.send);

        btnCapture.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                camera.takePicture(null, picCalBac, picCalBac);
            }
        });


    Camera.PictureCallback picCalBac = new PictureCallback() {

        public void onPictureTaken(byte[] data, Camera camera) {
            if (data != null) {
                mBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
            }
        }
    };

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        if (previewRunning) {
            camera.stopPreview();
        }
        try {
            camera.setPreviewDisplay(surfaceHolder);
        } catch (IOException e) {
            Log.d("IOException", e.getMessage());
        }
        camera.startPreview();
        previewRunning = true;
    }

    public void surfaceCreated(SurfaceHolder arg0) {
        camera = Camera.open(0);
    }

    public void surfaceDestroyed(SurfaceHolder arg0) {
        camera.stopPreview();
        previewRunning = false;
        camera.release();
    }
}

Answer 1

You might have gone through this link while searching for the error.

Though I never had such issue, after reading on the Internet, this is what I understand:

Description :

ANR or Application Not Responding error occurs when a process
on the main thread takes too long (something like > 5 seconds). Android
kills that process and any related by design to spare the device’s
resources.

The solution is to run resource-expensive tasks on another thread, and
then post, or update the main thread accordingly.

See This : Android ANR keyDispatchingTimedOut

So in your case you may be conflicting two different threads from the one that keeps running for long time and Android kills them. The next related code also gets affected.

So better classify your code, write each new task in different Thread,Handler and if you’re doing a UI task, use runOnUIThread. Async Task is also very Handy.

Another thing is to try to remove dependency of code on other. Write some default values and from that you can send user back to first task if it’s not done properly.

I believe the error is from your coding Style, not because of any specific error in your code.

You need to improve your that particular code to perform efficiently and for that see these 2 links:

1. Design for Responsiveness
2. Painless Threading

EDIT:

This I read somewhere and found effective is,

How to investigate ANR ?

First, go over your code and look for vunerable spots and long running operations. Examples may include using sockets, locks, thread sleeps, and other blocking operations from within the event thread. You should make sure these all happen in separate threads. If nothing seems the problem, use DDMS and enable the thread view. This shows all the threads in your application similar to the trace you have. Reproduce the ANR, and refresh the main thread at the same time. That should show you precisely whats going on at the time of the ANR

Also If ANR is caused because of Threads ?

you can user Service for that,
So your app can do the time consuming tasks inside service.onStart(),
passing data (for example) in the intent used to start the service.

However, Services execute on the main application thread. If a separate
thread is needed, it can be created by the service inside onStart().

There is already a built-in class that does this: IntentService

Also found one helpful library application SalomonBrys/ANR-WatchDog