如何从 Firebase 实时数据库获取数据到 ListView？

Question

-Quiz
  -MCQ
    -Question
       -1831
         -783444
           -//still got data
         -234567
           -//still got data

Above is my Firebase realtime database and I want only show the 783444 and 234567 to my ListView and clickable to next activity.

Please give some advise to solve my problem. Thank you very much.

Answer 1

To get only those keys, 783444 and 234567 in a ListView , please use the following lines of code:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference ref = rootRef.child("Quiz").child("MCQ").child("Question").child("1831");
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        ArrayList<String> list = new ArrayList<>();
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String key = ds.getKey();
            list.add(key);
        }
        ListView listView = (ListView) findViewById(R.id.list_view);
        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(getApplicationContext(), android.R.layout.simple_list_item_1, list);
        listView.setAdapter(arrayAdapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                //Go to next activity
            }
        });
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {}
};
ref.addListenerForSingleValueEvent(valueEventListener);