Cancel/dismiss notification on icon

Question

I'm using OneSignal to display notifications to my user. The notifications work fine but, I noticed that if I cancel the notification "swiping" it in the notification bar then the notification remains for ever, here is a image showing the notification on the app icon that I would like to dismiss as soon as the application is opened:

I have seen this question, showing that I can dismiss the notification by doing:

NotificationManager nMgr = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
if (nMgr!=null) {
    nMgr.cancelAll();
}

But this cancels the notification in that notification bar, but the notification on the app icon remain, any idea how I can cancel it as soon as my application is opened?

EDIT 1:

I added the above in OnCreate , also in OnResume as mentioned in the answer below, but the 1 still gets displayed on the app icon.

Answer 1

I found that with OneSignal I can disable badges by adding the following in my manifest:

<application ...>

    <meta-data android:name="com.onesignal.BadgeCount" android:value="DISABLE" />

</application>

Starting with 8.0 (API level 26), notification badges can be disabled by calling the following :

String id = "my_channel_01";
CharSequence name = getString(R.string.channel_name);
String description = getString(R.string.channel_description);
int importance = NotificationManager.IMPORTANCE_LOW;
NotificationChannel mChannel = new NotificationChannel(id, name, importance);
mChannel.setDescription(description);
mChannel.setShowBadge(false);

NotificationManager mNotificationManager =
    (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.createNotificationChannel(mChannel);

With this library I can also set badge numbers manually after disabling them. Note, this only supports certain manufactured devices (Samsung, LG, Sony and HTC).

Answer 2

the above code is perfect but the thing you need to do is you need to add this code inside the onResume() Like

@Override
protected void onResume() {
    super.onResume();

    NotificationManager nm = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
    nm.cancelAll();
}

thats do the trick for you . :)