android - What happens if a firebase url doesnot exist and we try to add a listener to it?

Question

I am developing an application in which I ask the user to enter the city and state name and return certain location in that place. But the problem is that if the specified state or city doesn't exist in my Firebase then my Progress Dialog,which I am supposed to dismiss when the listener has triggered, keeps moving and no action is triggered further.

Here is that portion of my code:

//state = get from user //city = get from user

mapProgress.show();

firebase.child("markers").child(state).child(city).addChildEventListener(new ChildEventListener() {
                       @Override
                       public void onChildAdded(final DataSnapshot dataSnapshot, String s) {
                                mapProgress.dismiss();

                            if (dataSnapshot.exists()) {
                                        //do something
                            }
                            else
                                Toast.makeText(MainActivity.this, "No data found!", Toast.LENGTH_SHORT).show();
                        }

                        @Override
                        public void onChildChanged(DataSnapshot dataSnapshot, String s) {

                        }

                        @Override
                        public void onChildRemoved(DataSnapshot dataSnapshot) {

                        }

                        @Override
                        public void onChildMoved(DataSnapshot dataSnapshot, String s) {

                        }

                        @Override
                        public void onCancelled(FirebaseError firebaseError) {
                            mapProgress.dismiss();
                            Toast.makeText(MainActivity.this, "Cancelled.", Toast.LENGTH_SHORT).show();
                        }
                    });
                }`

Answer 1

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