title: How to pause UI thread until Firebase query is finished?
body: <p>so my question says it all. In onCreate I am attempting to query objects, but I want the UI thread to wait until im done querying all my objects so I can use them to create views that my user can see. Does anyone know how to go about doing that with example code?</p>
  
  <p>here is how i am querying.</p>
  
  <pre><code> Firebase cardReference = mRef.child("aReference");
          cardReference.addValueEventListener(new ValueEventListener() {
              @Override
              public void onDataChange(DataSnapshot dataSnapshot) {
                  for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                      CardModel fireBaseCard = dataSnapshot1.getValue(CardModel.class);
                      testCardModelArray.add(fireBaseCard);
                      cardStack.setCardModelIDInArrayList(fireBaseCard.getCardID());
                  }
                  setUpCardStack();
              }
  
              @Override
              public void onCancelled(FirebaseError firebaseError) {
  
              }
          });
  </code></pre>
  
  <p>Hope you guys can help!</p>