从Firebase检索数据 [英] Retreiving data from firebase

问题描述

这是我的Android代码，用于从Firebase实时数据库中检索数据:

Here is my android code for retrieving data from firebase real-time database:

package com.example.firebaseapp;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import`enter code here` android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

public class MainActivity extends AppCompatActivity {

    Button f;
    TextView status;

    FirebaseDatabase database = FirebaseDatabase.getInstance();
    DatabaseReference myRef = database.getReference("light");

    @Override
    protected void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        f=(Button)findViewById(R.id.button);
        status=(TextView) findViewById(R.id.lightstatus);

        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                String value = dataSnapshot.getValue(String.class);
                status.setText(value);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError){
                status.setText("Could not fetch data..");
            }
        });
    }

    public void lighton(View view){
        myRef.setValue(1);
    }

    public void lightoff(View view){
        myRef.setValue(0);
    }
}

该应用程序正在正确编译，但是每当我运行该应用程序时，该应用程序都会崩溃，并显示错误消息不幸的是，Firebase应用程序已停止".请帮我解决这个问题.这是我的数据库中的一个片段:

The app is compiling properly but whenever I am running it the app crashes with the error message "Unfortunately, Firebase App stopped". Please help me solve this problem. Here is a snippet from my database:

推荐答案

将字符串更改为Integer或Long，因为light值不是String.

Change String to Integer or Long as light value is not String.

public class MainActivity extends AppCompatActivity {

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