快照值返回 null firebase

Question

I am getting some image ids from firebase but it always returns null even though i am 100% sure data is there and the key names are correct here is my code and firebase database:

String storeidd = getIntent().getStringExtra("storeid");
Query query = FirebaseDatabase.getInstance().getReference().child("Member").child(storeidd).child(childDataSnapshot.getKey()).child("proImages").orderByChild("ImageID").equalTo("1597332319044_0.null");
query.addValueEventListener(new ValueEventListener() {
      @Override
      public void onDataChange(DataSnapshot snapshot) {
           if (snapshot.exists()){
                System.out.println(snapshot.child("ImageID").getValue().toString()); // <-  returns null
                itemArrayList.add(new ClassListItems(childDataSnapshot.child("proname").getValue().toString(),snapshot.child("ImageID").getValue().toString(),childDataSnapshot.child("proprice").getValue().toString(),childDataSnapshot.child("prodesc").getValue().toString()));
                myAppAdapter = new MyAppAdapter(itemArrayList, showProducts.this);
                listView21.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
                listView21.setAdapter(myAppAdapter);
            }
      }

      @Override
      public void onCancelled(@NonNull DatabaseError error) {

      }
});

Also when I print it as System.out.println(snapshot.getValue().toString()); It gives me {-MEcQEJFZCO5Cr0aJSbg={ImageID=1597332319044_0.null}} Any ideas?

Answer 1

You need to iterate inside the snapshot to be able to get the data:

public void onDataChange(DataSnapshot snapshot) {
    if (snapshot.exists()){
        for(DataSnapshot ds : snapshot.getChildren()){
            String imageID = ds.child("ImageID").getValue(String.class);
        }
    }
}