问Firebase数据库不是Working..No响应

EN

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

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


        Button button=(Button)findViewById(R.id.bt);
        button.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        TextView textView=(TextView)findViewById(R.id.tv);
        DatabaseReference databaseReference= FirebaseDatabase.getInstance().getReference();
        databaseReference.child("User").setValue(textView.getText().toString());
    }
}