Develop Reference

How can I turn off localbroadcast listener in recyclerview adapter? Of is there a better way to communicate with an activity called from it?

I'm new to SO and fairly new to coding, so please accept my apologies in advance if I break rules or expectations here.
I have an unusual setup involving two recyclerViews, which I'll explain here and also paste a simplified version of the code below (as there is so much not relevant to this question).
In what I'll call verticalRecyclerViewActivity, a verticalRecyclerViewAdapter is called, with data it fetches from Firebase and loads into arrayLists.
If the user clicks on an item in the vertical recyclerview, a new dialog fragment which I'll call horizontalRecyclerViewDialogFragment is inflated, and that loads what I'll call horizontalRecyclerView (which has similar items to the vertical one, in more detail, with options to click on them to review them).
If the user clicks on an item in the horizontalRecyclerView, a new activity which I'll call reviewItem is started (through an Intent). When the user submits their review, it finishes and returns (through the backstack) to the horizontal RecyclerView. That can also happen if they press the back button without actually submitting a review. That all works fine, but I need the horizontalRecyclerView to show that they have (or haven't) reviewed the item and state the score they gave it in a review.
Calling notifyDataSetChanged won't work for this because of how information comes through two recyclerViews and Firebase calls (or, at least, it would be very inefficient).
I've tried using startActivityForResult (I know it's deprecated, but if I could get that to work I could try using the newer equivalent which I don't yet understand) but the problem is that the result is returned to the original (VerticalRecylcerView) activity, which is two recyclerView adapters and one fragment beneath what needs to be updated, and I don't know how to pass that data to the horizontal Recyclerview.
I've also tried using interfaces but was unable to pass it through the Intent (tried using Parcelable and Serializable, but it seems neither can work in this situation?).
Since the review is updated on Firebase, I could have the horizontal Recyclerview listen for a change, but that seems very inefficient?
So I've found a solution using localBroadcast (which I know is also deprecated). The Intent (with the review score) is transmitted when it is reviewed and received in the horizontal recyclerView adapter. But when and how should I unregister the adapter? Ideally the receiver would be turned on when the user goes to the Review activity and turned off once the user returns from that activity and the (horizontal) recyclerView holder is updated, whether the review is successfully submitted or whether the user just presses the back button and never submits a review.
My question is similar to this one: How to unregister and register BroadcastReceiver from another class?
That is noted as a duplicate of this one: How to unregister and register BroadcastReceiver from another class?
There's a lot in those questions I don't understand, but the important difference I think between their and my cases is that I would just like the receiver to know when a review is submitted, and ideally be unregistered then, or possibly when the viewHolder is recycled, which I tried but also didn't work since it's not connected to the viewHolder (should it be?).
Any help would be much appreciated, thank you!
public class verticalRecyclerViewActivity extends AppCompatActivity {
// Loads an XML file and assembles an array from Firebase.
mVerticalRecyclerView = findViewById(R.id.verticalRecyclerView);
verticalRecyclerViewAdaptor mVerticalRecyclerViewAdaptor = new verticalRecyclerViewAdaptor (this); // also pass other information it needs
mVerticalRecyclerView .setAdapter(mVerticalRecyclerViewAdaptor);
}
public class verticalRecyclerViewAdaptor extends RecyclerView.Adapter<verticalRecyclerViewAdaptor.singleHolder> {
// Usual recyclerView content
holder.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
horizontalRecyclerViewFragment mHorizontalRecyclerViewFragment = new horizontalRecyclerViewFragment();
// lots of arguments passed it needs.
FragmentManager fragmentManager = ((FragmentActivity) view.getContext()).getSupportFragmentManager();
mHorizontalRecyclerViewFragment.show(fragmentManager, null);
}
public class mHorizontalRecyclerViewFragment extends DialogFragment {
public Dialog onCreateDialog(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mContext = getActivity().getApplicationContext(); // Not sure why I need this, but it works.
View horizontalRecyclerViewView = getActivity().getLayoutInflater().inflate(R.layout.horizontal_recyclerview_holder, new CardView(getActivity()), false);
Dialog horizontalRecyclerViewDialog = new Dialog(getActivity());
horizontalRecyclerViewDialog.setContentView(horizontalRecyclerViewView);
mHorizontalRecyclerView = horizontalRecyclerViewView.getRootView().findViewById(R.id.horizontalRecyclerView);
mHorizontalRecyclerViewAdapter = new horizontalRecyclerViewAdapter (mContext)
// Other arguments passed
mHorizontalRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity(),
LinearLayoutManager.HORIZONTAL, false));
mHorizontalRecyclerView.setAdapter(mHorizontalRecyclerViewAdapter);
}
public class horizontalRecyclerViewAdapter extends RecyclerView.Adapter<horizontalRecyclerViewAdapter.horizontalRecyclerViewHolder> {
public horizontalRecyclerViewAdapter(){}
// Blank constructor and also one with lots of arguments for it to work.
public horizontalRecyclerViewAdapter.horizontalRecyclerViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.horizontal_recyclerview_adaptor_holder, parent, false);
return new horizontalRecyclerViewAdapter.horizontalRecyclerViewHolder(view);
}
public void onBindViewHolder(#NonNull horizontalRecyclerViewHolder holder, int position) {
// Connect up various views.
holder.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
LocalBroadcastManager.getInstance(mContext).registerReceiver(reviewSubmittedListener, new IntentFilter("reviewSubmitted"));
Intent reviewNow = new Intent(view.getContext(), ReviewActivity.class);
// Put extra details with the intent
view.getContext().startActivity(reviewNow);
}
BroadcastReceiver reviewSubmittedListener = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent reviewFinishedIntent) {
int reviewScore = reviewFinishedIntent.getExtras().getInt("reviewScore");
// Update the horizontal RecyclerView with the information received from the review Activity.
}
};
}
public class ReviewActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_review_item);
// Set up the review, using Firebase and data passed through the intent.
}
public void submitReview() {
// Check that the review is complete/valid and submit it through Firebase
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(ReviewItemActivity.this);
Intent reviewFinishedIntent = new Intent("reviewSubmitted");
reviewFinishedIntent.putExtra("reviewScore", overallScore);
LocalBroadcastManager.getInstance(this).sendBroadcast(reviewFinishedIntent);
finish();
}

If you are using RxJava you can use the RxBus else you can use one of many EventBus implementation for this.
If that is not the path you want to take then you can have a shared view model object that can be used only for communication between fragments see this article.

How to start a FlutterActivity and change route

Im trying to make an alarm clock using flutter, and start the flutter activity with a path to the alarm ("/alarm" path). I have acccomplished starting the MainActivity using MethodChannels, but i need to somehow route to "/alarm", but calling getFlutterView().pushRoute("/alarm") does not do anything. The activity just starts in the main view instead of alarm route.
Thanks in advance!
I have managed to startActivity using MethodChannels, but when calling getFlutterView().pushRoute("/alarm") in onCreate, it does not change the route.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GeneratedPluginRegistrant.registerWith(this);
// This does not change the route (setInitialRoute doesn't work either)
getFlutterView().pushRoute("/alarm");
new MethodChannel(getFlutterView(), CHANNEL).setMethodCallHandler(
new MethodCallHandler() {
#Override
public void onMethodCall(MethodCall call, Result result) {
if (call.method.equals("setAlarm")) {
// pushRoute works here, but not in onCreate
getFlutterView().pushRoute("/alarm");
} else {
result.notImplemented();
}
}
}
);
}
Expected results: Change the route to "/alarm"
Actual results: Nothing happens, the activity gets opened on initial route eg. the main page

Found the solution,
pushRoute() or setInitialRoute() doesn't work until the View has been inflated.
Here is the code that works:
FlutterView.FirstFrameListener mListener = new FlutterView.FirstFrameListener() {
#Override
public void onFirstFrame() {
getFlutterView().pushRoute("/alarm");
}
};
getFlutterView().addFirstFrameListener(mListener);

Lollipop+ Unbind BeaconManager not working

I am trying to implement beacon functionality in my Android application.
Unfortunately there are a few strange behaviours I couldn't solve yet.
I am using the Android Beacon Library in Version 2.15 and Android 6.0.1.
I have an Activity
class MainActivity extends AppCompatActivity implements BeaconConsumer
where I want to search for nearby beacons. I initialize the BeaconManager like
private BeaconManager m_beaconManager;
[...]
m_beaconManager = BeaconManager.getInstanceForApplication(this);
m_beaconManager.getBeaconParsers().add(new BeaconParser().setBeaconLayout(BeaconParser.EDDYSTONE_URL_LAYOUT));
m_beaconManager.bind(this);
in the onCreate() method.
The way I search for beacons
#Override
public void onBeaconServiceConnect() {
m_beaconManager.addRangeNotifier(new RangeNotifier() {
#Override
public void didRangeBeaconsInRegion(Collection<Beacon> collection, Region region) {
// do something
}
});
try {
m_beaconManager.startRangingBeaconsInRegion(m_region);
} catch(RemoteException e) {
e.printStackTrace();
}
}
works perfectly fine.
In my application I want to display these beacons in a list and if I click onto one of them I want to start a new activity with more informations about the beacon (MAC address, distance etc.).
My current approach is to unbind my BeaconManager in the onPause() method and create a whole new BeaconManager in my new Activity. This also works flawless.
But a soon as I finish() my second activity it does not stop searching for beacons. I also unbind my BeaconManager like so
#Override
public void onPause() {
super.onPause();
m_beaconManager.unbind(this);
}
#Override
public void onDestroy() {
super.onDestroy();
m_beaconManager.unbind(this);
}
#Override
public void onStop() {
super.onStop();
m_beaconManager.unbind(this);
}
but back in my MainActivity I get 2 searches for beacons. One from my MainActivity and the other one from my already finished second activity.
Furthermore if I click on another item of my list which means I create my second activity again, it looks for the beacon from the first start and the new one. Each new click on the list adds a new search to the existing ones.
I already searched for known Bugs but there is nothing similar.
What am I doing wrong?

In order to prevent duplicate callbacks, in addition to unbinding, you should call (a) stopRangingBeaconsInRegion(...) and (b) removeRangeNotifier(...). To remove the notifier you will need to keep a reference to your callback class.

Notification Listener - onNotificationPosted doesn't work

I'have tried all kind of solutions and code but any of this solutions worked for me, and I don't know why. Please help me.
My MainActivity code is:
if(isNotificationServiceEnabled())
{
Intent i= new Intent(this,NotificationsService.class);
i.putExtra("command", "get_status");
startService(i);
}
else
startActivity(new Intent(Settings.ACTION_NOTIFICATION_LISTENER_SETTINGS));
Now I'm just tryng to check if the service read a nostification posted, but from log i can only see that it enters in onCreate method but no in onNotificationPosted.
This is the code for my service class:
public class NotificationsService extends NotificationListenerService {
#Override
public void onListenerConnected(){
Log.d(TAG, "Connected");
}
#Override
public void onNotificationPosted(final StatusBarNotification sbn){
Log.d(TAG,"got it");
}
I have tried also solutions with broadcast service , but it still doesn't work.
Thanks.

I have found the solutions. In my code I had some problems, but then I tested other code about notification listener in an other project, and It worked. So then I modify my code and now it works.
About notification lisener You don't need to launch the service, because when you launch the app the service is launched. So I just made this changes to my code:
Main
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(!isNotificationServiceEnabled())
{
startActivity(new Intent(Settings.ACTION_NOTIFICATION_LISTENER_SETTINGS));
}
}
#Override
protected void onDestroy() {
super.onDestroy();
}
And in the service I just put the log code to write in debug the notification package.
Instead I got that broadcast are just used to exchange the data between service and my activity, for example to write the notifications in a textview.

Android - creating a "to next page" button

i have this code but every time i run the app and click on my button it crashes and i don't get why.. am i doing something wrong here any help would be great thanks
im trying to got to the "Sec.class" page/class
public class APPcalendarActivity extends Activity implements OnClickListener{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
View continueButton = findViewById(R.id.continue_button);
continueButton.setOnClickListener( (OnClickListener) this);
}
//#Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.continue_button:
Intent i = new Intent(this, Sec.class);
startActivity(i);
break;
}
}
THIS IS WHAT I WAS MISSING IN THE MANISFEST.XML FILE
and i want to slap the person who downgraded my question
<activity android:name=".Sec"
android:label="#string/sec" >
</activity>

Check that you've declared an <activity> tag for the Sec activity in your AndroidManifest.xml.
But posting (or simply reading) the crash stacktrace from logcat would be more instructive.

Without knowing what the error is, it is really hard to guess what the problem is, but usually when this happens, the button (continueButton in your case) could not be found in the layout. So make sure that you have a View with id continue_button in main.xml.