Wsrtjtyk

I am using LiveData and Room Database in a BroadcastReceiver.

The main idea is to perform a single query on the database (insert, remove, get) and forward the updated value to the caller.

Thanks to an Observer listening to the LiveData object, I am able to get the updated value. Then the value is forwarded to the caller via setResultData().

This is my BroadcastReceiver:

public class WordReceiver extends BroadcastReceiver {

...



    private List<Sring> mWordList;

    private WordItemViewModel mWordItemViewModel;

    private Observer<List<String>> mObserver;

    private boolean mActionPerformed = false;



...



    @Override

    public void onReceive(final Context context, final Intent intent) {

        final PendingResult result = goAsync();



        new Thread() {

            public void run() {

                manageActions(context, intent, result);

            }

        }.start()

    }



...



    private void manageActions(Context context, Intent intent, PendingResult result) {

        String action = intent.getAction();

        if (action == null) {

            return;

        }

        switch (action) {

            case WordReceiver.ACTION_ADD_WORD:

                initVariables(context, result);

                mActionPerformed = true;

                mWordItemViewModel.insert(intent.getStringExtra(WordReceiver.EXTRA_WORD);

                break;

            case WordReceiver.ACTION_REMOVE_WORD:

                initVariables(context, result);

                mActionPerformed = true;

                mWordItemViewModel.delete(intent.getStringExtra(WordReceiver.EXTRA_WORD);

                break;

            case WordReceiver.ACTION_GET_WORDS:

                // mActionPerformed is set to true because there is no action to perform

                mActionPerformed = true;

                initVariables(context, result);

                break;

            default:

                result.abortBroadcast();

                break;

        }

    }

}

The Observer and the AndroidViewModel are initialized this way:

private void initVariables(final Context context, final PendingResult result) {

    mWordItemViewModel = ViewModelProvider.AndroidViewModelFactory.getInstance((Application) context.getApplicationContext()).create(WordItemViewModel.class);



    mObserver = new Observer<List<String>>() {

        @Override

        public void onChanged(@Nullable final List<String> wordList) {

            mWordList = wordList;



            if (mActionPerformed) {

                mWordItemViewModel.getAllWordItems().removeObserver(this);



                if (mWordList != null) {

                    String wordListText = TextUtils.join(",", mWordList);

                    result.setResultData(wordListText);

                }

                result.finish();

            }

        }

    };



    mWordItemViewModel.getAllWordItems().observeForever(mObserver);

}

This works, but not always !

Sometimes the wordList parameter in onChanged() takes into account the added/removed Word, sometimes not.

According to https://developer.android.com/reference/android/arch/lifecycle/LiveData#getvalue

Returns the current value. Note that calling this method on a
background thread does not guarantee that the latest value set will be
received.

I am not using getvalue(), but I wonder if the onChanged() method may have the same behavior.

Thanks a lot...