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 DatabaseReference Ref = FirebaseDatabase.getInstance().getReference(Constants.Client + "/" + path);
 Ref.keepSynced(true);
 Ref.addValueEventListener(new ValueEventListener() 
 @Override
 public void onDataChange(DataSnapshot dataSnapshot) 

 

 @Override
 public void onCancelled(DatabaseError databaseError) 

 
 );

I understand that valueEventListener runs in a new thread, should I actually remove this at any point of time for proper thread management?(example for not too many threads running in parallel), If yes, how to do it?

When talking about listeners, yes, you need to remove them accordingly to the life-cycle of your activity and for this you need to use the following line of code:

databaseReference.removeEventListener(valueEventListener);

Remember if you don't do this, you'll end up wasting your battery and bandwidth. So:

1. If you have added the listener in onStart you have to remove it in onStop.


2. If you have added the listener in onResume you have to remove it in onPause.


3. If you have added the listener in onCreate you have to remove it in onDestroy.

But remember onDestroy is not always called, so the last option in not always a good choice.

There is another approach in which there is no need to remove the listener and that is when using addListenerForSingleValueEvent:

Add a listener for a single change in the data at this location.

To remove the ValueEventListener, you can then do this:

Remove the anonymity of the listener.

Change the code from this:-

 Ref.addValueEventListener(new ValueEventListener() 
 @Override
 public void onDataChange(DataSnapshot dataSnapshot) 

 

 @Override
 public void onCancelled(DatabaseError databaseError) 

 
 );

into this:

 ValueEventListener listener= new ValueEventListener() 
 @Override
 public void onDataChange(DataSnapshot dataSnapshot) 

 

 @Override
 public void onCancelled(DatabaseError databaseError) 

 
 );
Ref.addValueEventListener(listener);

Now you will be able to remove the listener:

 @Override
public void onDestroy() 
if (Ref != null && listener != null) 
 Ref.removeEventListener(listener);
 
 

You need to remove it, so the listener does not stay running in the other activity lifecycles like onDestroy()