如何在Firebase中按子值排序

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("your_reference");

Query query = ref.orderByChild("age");

query.addChildEventListener(new ChildEventListener() {
    @Override
    public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
        // 处理数据添加事件
    }

    @Override
    public void onChildChanged(DataSnapshot dataSnapshot, String previousChildName) {
        // 处理数据变化事件
    }

    // 其他监听方法...
});

query.addChildEventListener(new ChildEventListener() {
    @Override
    public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
        for (DataSnapshot childSnapshot : dataSnapshot.getChildren()) {
            String key = childSnapshot.getKey();
            Object value = childSnapshot.getValue();
            // 处理数据
        }
    }

    // 其他监听方法...
});