how to know if firebase ChildEventListener found child ? [android]

Question

so I\'m trying to get users key by their email and the problem is that I dont know inside my code if the query actually found something or not .. so I\'m assuming if I\'m in

Answer 1

The methods of a ChildEventListener get called when the relevant event happened. So onChildAdded() will be called when a child has been added. For this reason you cannot easily use a ChildEventListener to detect if a child exists.

The easiest way to detect if a child exists, is to use a ValueEventListener:

public void searchemail(String email){

  Firebase ref = new Firebase("https://<myfirebase>.firebaseio.com/users");
  Query queryRef = ref.orderByChild("Email").equalTo(email);


   ValueEventListener listener = new ValueEventListener() {

     @Override
     public void onDataChanged(DataSnapshot snapshot) {
       if (snapshot.exists()) {
         for (DataSnapshot child: snapshot.getChildren()) {
           homeintent.putExtra("key", child.getKey());
           startActivity(homeintent);
           break; // exit for loop, we only want one match
         }
       }
       else {
         Toast toast = Toast.makeText(this, "email not found", Toast.LENGTH_SHORT);
       }
     }
   };
   queryRef.addValueEventListener(listener);
}