AsyncTask - unchecked call to execute(Params...)

Issue

I was looking for answer for hours but without result.

My app is using cameraCaptureSessions.setRepeatingRequest and saving/refreshing into TextureView privateTextureView.

I want to take a picture from TextureView -> apply filter using AsyncTask -> save it to the ImageView. But getting warning "unchecked call to execute(Params...) as a member of the raw type AsyncTask"

Application falls on button click(AsyncTask execute). Where am I wrong?

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        .
        .
        .
        privateTextureView = (TextureView)findViewById(R.id.textureView);
        privateTextureView.setSurfaceTextureListener(textureListener);

        myTask = new ApplyFilterTask();

        privateBtnGetCapture.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                pictureBitmap = privateTextureView.getBitmap();

                //Start MyTask
                myTask.execute(pictureBitmap);
            }
        });
    }

protected class ApplyFilterTask extends AsyncTask<Bitmap, Bitmap, Bitmap> {
        @Override
        protected void onPreExecute() {
            int color = Color.parseColor("#ffa500");
            privateImageView.setColorFilter(color);
        }

        @Override
        protected Bitmap doInBackground(Bitmap... bitmaps) {
            Bitmap bmp = bitmaps[0];
            try {
                ImageFilters filter = new ImageFilters();
                bmp = filter.applyContrastEffect(bmp, 5);
                publishProgress(bmp);
            } catch (Exception e) {
                //System.out.println("Error!!!! " + e);
            }
            return bmp;
        }

        @Override
        protected void onProgressUpdate(Bitmap... bm) {
            System.out.println("TestProgress");
            privateImageView.setImageBitmap(bm[0]);
        }
        /*
        protected void onPostExecute(Bitmap... bm) {
            System.out.println("TestExecude");
            privateImageView.setImageBitmap(bm[0]);
        }*/
    }

Solution

The application failure mentioned by you seems to be due to multiple usages of the same AsyncTask. An Asynctask can be used only once. As mentioned in the official documentation :

The task can be executed only once (an exception will be thrown if a second execution is attempted.)

Your code creates a single myTask object that is used every time in the OnClick event listener. Instantiate a new AsyncTask everytime to avoid the application failures, as shown below.

    privateBtnGetCapture.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            pictureBitmap = privateTextureView.getBitmap();
            AsyncTask<Bitmap, Bitmap, Bitmap> myTask = new ApplyFilterTask();
            //Start MyTask
            myTask.execute(pictureBitmap);
        }
    });

The warning mentioned by the IDE is however a separate issue that has to do with the declaration of myTask. You seem to have declared myTask as AsyncTask and not as AsyncTask<Bitmap, Bitmap, Bitmap> or ApplyFilterTask. Change the declaration and the warning would disappear.

Answered By - Pranjal