Firebase null pointer exception

Question

I am getting null pointer exception in firebase I knows that there is not any value like that to which database reference I am giving but I wants that when the value is generated then it will be shown automatically... Just wants to get that single value everytime it is created on the firebase but its giving me null pointer exception on the line String val =.....

Please help me ...

final DatabaseReference dtt = database.getReference("/trial/trials/");
    dtt.addValueEventListener(new ValueEventListener() {

        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String val= dataSnapshot.child("myvalue").getValue().toString();
            if(val!=null)
            {
                Log.e("not null------","---------------");
            }else
            {
                Log.e("null------","---------------");
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

Please help me.....Please ..

Just a guess because we don't have much information to go off of here but `dataSnapshot.child("myvalue")` is probably the culprit... — bwegs, Jul 04 '16 at 13:36
Yaa can you suggest me somthing by which I cant get null pointer exception please — Kawal Singh, Jul 04 '16 at 13:38
I have tried by removing child and directly giving it in the reference Still getting error.. — Kawal Singh, Jul 04 '16 at 13:42

Mohamed Yehia · Answer 1 · 2016-12-03T09:50:12.387

final DatabaseReference dtt = database.getReference("/trial/trials/");
dtt.addValueEventListener(new ValueEventListener() {

    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        String val= dataSnapshot.child("myvalue").getValue(String.class);
        if(val!=null)
        {
            Log.e("not null------","---------------");
        }else
        {
            Log.e("null------","---------------");
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {

    }
});

score 2 · Accepted Answer · answered Jul 04 '16 at 13:47

You are using getValue() in wrong way. Should be

String val= dataSnapshot.child("myvalue").getValue(String.class);

To check, if value exists you can convert dataSnapshot to Hashmap, like this

HashMap<String, Object> hashmap = (HashMap) dataSnapshot.getValue();
String val= hashmap.get("myvalue");

Firebase null pointer exception

2 Answers2