Firebase實時數據庫無法正常工作

Question

當我嘗試向Firebase數據庫添加數據時，沒有任何反應

   @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    database=FirebaseDatabase.getInstance();
    reference=database.getReference("comment");
    uploadButton=(ImageButton) findViewById(R.id.uploadButton);
     uploadButton.setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View v) {


       reference.setValue("zizo");
     }
 });

注意：電話已連接到互聯網，我已寫了用戶使用互聯網的權限

Answer 1

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    DatabaseReference database = FirebaseDatabase.getInstance().getReference().child("comment");
     uploadButton=(ImageButton) findViewById(R.id.uploadButton);
    uploadButton.setOnClickListener(new View.OnClickListener() {
      @Override
        public void onClick(View v) {


   reference.setValue("zizo");
 }
 });