在添加Firebase子项后，在Android中获取通知 [英] Get a Notification in Android when a Firebase child has been added

问题描述

我试图通过使用侦听器将Fire base Database子数据添加到数据库时得到一个android通知，但无法获取通知。我已经编写了这个小测试应用程序，它不显示通知，当应用程序运行，甚至在后台。有人可以看看这个，帮助我，我仍然是一个初学者，一点点的帮助将是美好的！

 包com.fayaz.firebasenotify; 
 
导入android.content.Context; 
导入android.support.v7.app.AppCompatActivity; 
导入android.os.Bundle; 
导入android.util.Log; 
导入com.google.firebase.auth.FirebaseAuth; 
 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; 
导入android.app.NotificationManager; 
导入android.support.v4.app.NotificationCompat; 
导入android.view.View; 
 
 
 public class MainActivity extends AppCompatActivity {
 $ b $ private FirebaseDatabase myFirebaseRef = FirebaseDatabase.getInstance（）; 
 private DatabaseReference myRef = myFirebaseRef.getReference（）; 
 
 @Override 
 protected void onCreate（Bundle savedInstanceState）{
 super.onCreate（savedInstanceState）; 
 setContentView（R.layout.activity_main）; 
 
 
 
 NotificationCompat.Builder builder = new NotificationCompat.Builder（this）; 
 
 public void sendNotification（View view）{
 ValueEventListener valueEventListener = new ValueEventListener（）{
 @Override 
 public void onDataChange（DataSnapshot dataSnapshot）{
 builder.setSmallIcon（R.mipmap.ic_launcher）; 
 builder.setContentTitle（Firebase推送通知）; 
 builder.setContentText（您好，这是一个测试Firebase通知，新增了一个数据库子项）; 
 NotificationManager notificationManager =（NotificationManager）getSystemService（NOTIFICATION_SERVICE）; 
 notificationManager.notify（1，builder.build（））; 
 
 $ b @Override 
 public void onCancelled（DatabaseError databaseError）{
 Log.i（FirebaseError，databaseError.getMessage（））; 
} 
 
}; 
 myRef.addValueEventListener（valueEventListener）; 
 
 
 
 $ div $解析方案

应该使用ChildEventListener，



  super.onCreate（savedInstanceState）; 
 setContentView（R.layout.activity_main）; 
 mRootRef = FirebaseDatabase.getInstance（）。getReference（）; 
 builder = new NotificationCompat.Builder（this）; 
 mRootRef.addChildEventListener（new ChildEventListener（）{
 @Override 
 public void onChildAdded（DataSnapshot dataSnapshot，String s）{
 builder.setSmallIcon（R.mipmap.ic_launcher）; $ 
 builder.setContentTitle（Firebase推送通知）; 
 builder.setContentText（Hello this is a test Firebase notification，a new database child has been added）; 
 NotificationManager notificationManager =（NotificationManager ）getSystemService（NOTIFICATION_SERVICE）; 
 notificationManager.notify（1，builder.build（））; 
} 
 $ b @Override 
 public void onChildChanged（DataSnapshot dataSnapshot，String s）{
 
} 
 
 @Override 
 public void onChildRemoved（DataSnapshot dataSnapshot）{
 
} 
 
 @Override 
 public void onChildMoved（DataSnapshot dataSnapshot，String s）{
 
} 
 
 @Override 
 public void onCancelled（DatabaseError databaseError）{
 $ b} 
}）; 
  

确保您可以从数据库读取数据（检查安全规则）。 b $ b

I am trying to get an android notification when a Fire base Database child has been added to the database using listeners, but unable to get the notification. I have coded this little test app which doesn't show an notification when the app is run, or even on background. Can someone please look into this, and help me out, I am still a beginner, a little help would be wonderful!

package com.fayaz.firebasenotify;

import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import com.google.firebase.auth.FirebaseAuth;
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;
import android.app.NotificationManager;
import android.support.v4.app.NotificationCompat;
import android.view.View;


public class MainActivity extends AppCompatActivity {

private FirebaseDatabase myFirebaseRef = FirebaseDatabase.getInstance();
private DatabaseReference myRef =  myFirebaseRef.getReference();

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

}

NotificationCompat.Builder builder = new NotificationCompat.Builder(this);

public void sendNotification(View view) {
    ValueEventListener valueEventListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            builder.setSmallIcon(R.mipmap.ic_launcher);
            builder.setContentTitle("Firebase Push Notification");
            builder.setContentText("Hello this is a test Firebase notification, a new database child has been added");
            NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
            notificationManager.notify(1, builder.build());
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Log.i("FirebaseError", databaseError.getMessage());
        }

    };
    myRef.addValueEventListener(valueEventListener);
}
}

解决方案

You should use ChildEventListener,

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mRootRef = FirebaseDatabase.getInstance().getReference();
    builder = new NotificationCompat.Builder(this);
    mRootRef.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            builder.setSmallIcon(R.mipmap.ic_launcher);
            builder.setContentTitle("Firebase Push Notification");
            builder.setContentText("Hello this is a test Firebase notification, a new database child has been added");
            NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
            notificationManager.notify(1, builder.build());
        }

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

        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {

        }

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

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

Make sure you can read the data from the database (check security rules).

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