如何从firebase获取孩子的名字到listview android

Question

你好，我是Firebase的新手，你能帮我把孩子的名字从我的Firebase转到列表视图吗？

这是我的数据库 这是我的代码，但是不起作用

公共类教育扩展了AppCompatActivity {

private DatabaseReference fNotesDatabase;
ListView listView;
ArrayList<String> arraylist = new ArrayList<>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_education);

    Firebase.setAndroidContext(this);
    fNotesDatabase = FirebaseDatabase.getInstance().getReference().child("Notes").child("education").child();
    listView = (ListView) findViewById(R.id.listview);
    final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, arraylist);

    listView.setAdapter(arrayAdapter);

    fNotesDatabase.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            Map<String, Object> map = new HashMap<String, Object>();
            arraylist.add(map.values().toString());
            arrayAdapter.notifyDataSetChanged();
        }

        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {
            Map<String, Object> map = new HashMap<String, Object>();
            arraylist.add(map.values().toString());
        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {

        }

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

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });


}

}

Answer 1

如果要检索Notes下的直接子级，请尝试以下操作：

 ArrayAdapter adapter;
 ListView listView;
 ArrayList<String> arraylist = new ArrayList<>();

 listView = findViewById(R.id.listview);
 fNotesDatabase = FirebaseDatabase.getInstance().getReference().child("Notes");

 fNotesDatabase.addSingleValueEventListener(new ValueEventListener(){
  @Override
 public void onDataChange(DataSnapshot dataSnapshot) {

     for(DataSnapshot datas: dataSnapshot.getChildren()){
        String values = datas.getKey();
        arraylist.add(values); 
        adapter = new ArrayAdapter(Education.this, android.R.layout.simple_list_item_single_choice, arraylist);
        listView.setAdapter(adapter);

           }
       }

    @Override
  public void onCancelled(FirebaseError firebaseError) {

   }
});

首先在子项Notes上添加引用，然后在其内部循环并使用keys检索getKey()