在Camera Intent之后更新RecyclerView.Adapter

Question

So currently, I'm capturing an image and updating it in a RecyclerView using the Camera Intent:

 private void cameraIntent() {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(getActivity().getPackageManager()) != null) {
            File photoFile = null;
            try {
                photoFile = createImageFile();
            } catch (IOException ex) {
                Log.e(TAG, ex.getLocalizedMessage());
            }

            if (photoFile != null) {
                Uri uri = FileProvider.getUriForFile(getActivity().getApplicationContext(),
                        "packagename.fileprovider",
                        photoFile);
                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
                startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
            }
        }
    }

What happens prior to this is it'll trigger the intent from an setOnItemClickListener interface I have created within my RecyclerView.Adapter which is called in onCreate to populate the data from the web-server (or when triggered by setVisibleUserHint as they re-enter the fragment again).

//init camera data

if (isCamera) {
   cameraArray = object.getJSONArray(PROFILE_DETAILS_CAMERA_ARRAY_KEY);
   sortAdapter(true, object, cameraArray);
} else {
   galleryArray = object.getJSONArray(PROFILE_DETAILS_GALLERY_ARRAY_KEY);
   sortAdapter(false, object, galleryArray);
}

//settings adapters

cameraAdapter = new RecyclerViewAdapterGallery(getActivity(), array, true);
cameraAdapter.setOnItemClickListener(new RecyclerViewAdapterGallery.onItemClickListener() {
     @Override
     public void setOnItemClickListener(View view, final int position, String image, final boolean isCamera, boolean isLongClick) {
         clickResponse(view, position, image, isCamera, isLongClick, cameraAdapter, array, object);
     }
});
recyclerView.setAdapter(cameraAdapter);
cameraAdapter.notifyDataSetChanged();

What happens post is within the onActivityResult :

@Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case REQUEST_TAKE_PHOTO:
                if (resultCode != Activity.RESULT_CANCELED) {
                    if (resultCode == Activity.RESULT_OK) {
                        try {
                            handleBigCameraPhoto(finalPosition);
                        } catch (IOException e) {
                            Log.e(TAG, e.getLocalizedMessage());
                        }
                    }
                }
                break;
...
}

}

handleBigCameraPhoto:

private void handleBigCameraPhoto(int position) {
        Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        File f = new File(mCurrentPhotoPath);
        Uri contentUri = Uri.fromFile(f);
        mediaScanIntent.setData(contentUri);
        getActivity().sendBroadcast(mediaScanIntent);
        saveFile(f, false, position);
}

This works perfectly, it saves the file fine to the web-server but I want to update the adapter when that is successful, and of course I'm unable to restore the adapter object using outState or inState bundle.

cameraArray.put(position, parseFile.getUrl());
userObject.put(PROFILE_DETAILS_CAMERA_ARRAY_KEY, cameraArray);
userObject.saveInBackground(new SaveCallback() {
           @Override
           public void done(ParseException e) {
                if (e == null) {
                     if (cameraAdapter != null) {
                         cameraAdapter.updatePosition(cameraArray, position);
                     }
                } else {
                     Log.e(TAG, "failed " + e.getLocalizedMessage());
                }
           }
});

By this point I'm not sure why the cameraAdapter isn't updating as it's not returning null and is calling updatePosition().

public void updatePosition(JSONArray array, int position) {
        Log.e(TAG, "updatePositionCalled");
        this.imageList = array;
        notifyItemChanged(position);
}

If anyone can help me solve this mystery, that would be great! Also, if you need any more code or verification at all, let me know.

Note : I currently have the JSONArray of objects, position in the adapter and web-server object stored in the saveInstanceState bundle and is restored correctly (because when I come out of the ViewPager fragment and come back in, thus calling setUserVisibleHint it restores the adapter from the web-server correctly).

Update : I've created a getImageList() method inside the adapter and calling that after the supposed 'update', it's updating the list values but not the list?! So i really do think the problem is with notifyItemChanged(position)

 public JSONArray getImageList() {
        return imageList;
 }

// new call

if (e == null) {
    cameraAdapter.updatePosition(cameraArray, position);
    Log.e(TAG, cameraAdapter.getImageList().toString());
} else {
    Log.e(TAG, "failed " + e.getLocalizedMessage());
}

It literally prints out the corresponding values in the list, that has been passed to the adapter, but doesn't seem to update the UI.

Update II :

I've had two (now deleted) answers advising me to notifyDataSetChanged() , Which makes no difference at all and is counter-productive as it'll rebind the whole adapter within the fragment, thus making it slow. I'm already rebinding the dedicated position (supposedly) with notifyItemChanged() .

Note II : I'm offering a bounty, not for lazy and unresearched answers but for a solution with the very least an explanation, I'd like to know why it's going wrong, so I don't run into the same problem again (not a quick fix ). I'm already well aware of the different functionalities and components of a RecyclerView , RecyclerView.Adapter and RecyclerView.ViewHolder , I'm just having trouble in this particular scenario where the Activity is returning a result, but not updating the UI as it should.

Answer 1

Hey i think the issue is with the line this.imageList = array of below method,

public void updatePosition(JSONArray array, int position) {
        Log.e(TAG, "updatePositionCalled");
        this.imageList = array;
        notifyItemChanged(position);
}

Reason :

The this.imageList = array line is creating a new reference . It is not updating the old reference which was passed in the Recyclerview. Hence, notifyItemChanged(position); is refreshing the view but with the old reference of the array which has not been updated.

Solution:

You need to update the method as following:

public void updatePosition(String url, int position) {
        Log.e(TAG, "updatePositionCalled");
        this.imageList.put(position, url);
        notifyItemChanged(position);
}

And

userObject.put(PROFILE_DETAILS_CAMERA_ARRAY_KEY, cameraArray);
userObject.saveInBackground(new SaveCallback() {
           @Override
           public void done(ParseException e) {
                if (e == null) {
                     if (cameraAdapter != null) {
                         cameraAdapter.updatePosition(parseFile.getUrl(), position);
                     }
                } else {
                     Log.e(TAG, "failed " + e.getLocalizedMessage());
                }
           }
});

Update:

Also, replace notifyItemChanged(position) with notifyItemInserted(position) as new item is being inserted here in the Array.