NullPointerException When retrieving Value From Firebase

Question

I have created a database Related App. When I Run My App gets automatically Stopped . In The Log cat It Show NullPointerException on Datachange .

Here is My Firebase Code:

@Override
protected void onStart() {
    super.onStart();
    DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
    DatabaseReference ezzeearnRef = rootRef.child(firebaseAuth.getCurrentUser().getUid());
    ValueEventListener eventListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            long points = dataSnapshot.child("Points").getValue(Long.class);
            tv.setText(String.valueOf(points));
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
        }
    };
    ezzeearnRef.addValueEventListener(eventListener);
}

Possible duplicate of [What is a NullPointerException, and how do I fix it?](https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — AskNilesh, Nov 01 '17 at 04:24

score 0 · Answer 1 · answered Nov 01 '17 at 04:15

0

Hi I think you are getting datasnapshot as null then also you are going access value of datasnapshot please write following line and check,

Replace your following code:

long points = dataSnapshot.child("Points").getValue(Long.class);
            tv.setText(String.valueOf(points));

with following

if(dataSnapshot.exist()){
long points = dataSnapshot.child("Points").getValue(Long.class);
            tv.setText(String.valueOf(points));}

and try.

answered Nov 01 '17 at 04:15

Dhaval Solanki

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And Points = 0 ; In my database – Shawon Nov 01 '17 at 04:17
Can you post your database screenshot, And one more thing is app crashing when are you changing the value in the database or at initialization time? – Dhaval Solanki Nov 01 '17 at 04:21
its always crash . I tried by changing my points value . But not works :( – Shawon Nov 01 '17 at 04:23
I am not asking for every time but it crashing when you start your app or initialization time? – Dhaval Solanki Nov 01 '17 at 04:25
yes. When i start the App. Wait i am giving a screenshot . – Shawon Nov 01 '17 at 04:26
Change long to `Long` – Peter Haddad Nov 01 '17 at 04:35
@PeterHaddad Thanks Buddy :D . Its Now not showing error. Does it will works Same? – Shawon Nov 01 '17 at 04:37
Yes! No problem – Peter Haddad Nov 01 '17 at 04:38
If you are posting your database screenshot then we can check what actual problem, – Dhaval Solanki Nov 01 '17 at 04:38

NullPointerException When retrieving Value From Firebase

1 Answers1