Is notification mandatory while app is running(visible) for the foreground service in API>25

Question

From the stackoverflow and many blogs, i surely understand that foreground service never run without notification in API>25. But still i confuse that Is notification mandory whi

Answer 1

It's not possible to remove the notification while the foreground service is running, but it is possible to change your foreground service back into a "regular" service. This removes the need for a notification. In fact, the function to use,

stopForeground(boolean removeNotification)

...includes a removeNotification parameter just for that purpose. You service can switch from being "foreground" to "regular" on demand, by alternating calls to startForeground() and stopForeground().

In case it's not clear, you'd probably want to call stopForeground() whenever you have at least one Activity in a "started" state. This is something you'd have to track manually. Then, when the number of "started" activities reaches 0, you'd call startForeground().

EDIT

One approach is to use a bound service. Then, it's easy to call stopForeground() on it when you want.

Assume you have a single Activity. You can bind it to the service (see this doc or use one of these examples). Then your onServiceConnected() function could look like this (adapted from the Google example):

//MyActivity.java:

@Override
public void onServiceConnected(ComponentName className, IBinder service) {
    LocalBinder binder = (LocalBinder) service;
    mService = binder.getService();
    mService.stopForeground(true);      //This makes the notification go away
    bound = true;
}

...

@Override
protected void onStart() {
    super.onStart();
    // Bind to the service
    bindService(new Intent(this, MyService.class), this, Context.BIND_AUTO_CREATE);
}

@Override
protected void onStop() {
    super.onStop();
    // Unbind from the service
    if (bound) {
        Notification.Builder builder = new Notification.Builder(this, ANDROID_CHANNEL_ID)
            .setContentTitle(getString(R.string.app_name))
            .setContentText(text)
            .setAutoCancel(true);

        Notification notification = builder.build();
        mService.startForeground(1, notification);    //This brings the notification back! Service is already running, and continues to run.        

        unbindService(this);
        bound = false;
    }
}