Show Progress Dialog while Processing OnActivityResult

Question

I have written below codes where when user click attach button to select photos.

Below is code for same.

  Intent intent = new Intent();

                    intent.setType("*/*");
                    intent.setAction(Intent.ACTION_GET_CONTENT);
                    intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
                    startActivityForResult(Intent.createChooser(intent, "Select file to upload "), 1);

Below is code for OnActivityResult

 public void onActivityResult(int requestCode, int resultCode, Intent data) {


        if (requestCode == 1) {



            if (null != data) { // checking empty selection
                if (null != data.getClipData()) { // checking multiple selection or not
                    for (int i = 0; i < data.getClipData().getItemCount(); i++) {
                        Uri uri = data.getClipData().getItemAt(i).getUri();
                        Log.i(TAG, "Path" + getPath(uri));
                        filespath.add(getPath(uri));

                        BitmapFactory.Options options = new BitmapFactory.Options();
                        Bitmap bitmap = BitmapFactory.decodeFile(getPath(uri), options);
                        bitmaps.add(bitmap);
                    }
                } else {
                    Uri uri = data.getData();
                }
            }
        }


    }

Now user can select multiple photos and I realized that when photos are more than 10, I get warning too much work done on main thread. when user click on Done button after selecting photos, I have Recycler view where I am showing thumbnail of images selected by user before final upload.

Now issue is when user click Done and till it shows Thumbnail, how can I show ProgressDialog , handle freeze screen and avoid warning work done on main thread.

Answer 1

To keep the parsing and loading work off the main thread you can just wrap everything in an AsyncTask. Given the small amount of code shown, I don't know what functions do what in the above, so this might have to be adjusted a bit. Move all the parsing logic, etc to do in the background as such:

        AsyncTask<Void, Void, List<Bitmap>>() {
        @Override
        protected  void onPreExecute()
        {
            //show progress dialog
            //Are you trying to prevent the user from clicking on the UI while updating?
            //You can do something such as:
            getWindow().setFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,
                WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
        }

        @Override
        protected List<Bitmap> doInBackground(Void... voids) {
            //perform the logic, this will return a list of all the Bitmaps to onPostExecute
            //Do NOT perform any ui logic here.
        }

        @Override
        protected void onPostExecute(List<Bitmap> bitmaps) {
            //cancel progress dialog.
            //Update the UI with the response.
            //Clear the window lock:
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
        }
    };