title: how to know if firebase ChildEventListener found child ? [android]
body: <p>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 inside onchildadded that the query is successful and a child has been found so I will pass the key to another activity and stop current activity but when I run the app the whole code get executed .. I feel my way is kinda wrong but I didn't find any way to know if the query is sucsessful or a child is found .... if you have any idea pleas help ...</p>
  
  <pre><code>  public void searchemail(String email){
  
    Firebase ref = new Firebase("https://&lt;myfirebase&gt;.firebaseio.com/users");
      Query queryRef = ref.orderByChild("Email").equalTo(email);
  
  
       ChildEventListener listener = new ChildEventListener() {
  
          @Override
          public void onChildAdded(DataSnapshot dataSnapshot, String s) {
  
              userkey = dataSnapshot.getKey();
                homeintent.putExtra("key", userkey);
                 startActivity(homeintent);
                 finish();
                 return; 
                   // I want code to stop here 
  
          }}
      queryRef.addChildEventListener(listener);
  
        Toast toast = Toast.makeText(this, "email not found", Toast.LENGTH_SHORT); // Im assuming if Im here then no child is found but this always get executed before startactivity  
     }
  </code></pre>
  
  <p>OUTPUT :
  if email found -> toast will show then home activity will start...
  if email not found -> only toast will show..</p>