Firebase：通过应用程序退出来继续收听ChildEventListener

问题描述

我正在使用Firebase创建一个小聊天应用程序。我想 ChildEventListener 继续监听firebase数据库的位置，尽管我的应用程序在后台或退出。目前我正在注册它，当我的应用程序退出或关闭使用 finish（）之后，我的ChildEventListener的方法都没有被调用像 onChildAdded 或 onChildChanged 虽然我没有调用 removeEventListener 。我想让ChildEventListener一直运行背景。有没有这样做？

解决方案

使用服务来收听您的ChildEventListener

  public class ChildEventListener extends Service {
 @Override 
 public IBinder onBind（Intent intent）{
 return null; 
 
 @Override 
 public int onStartCommand（Intent intent，int flags，int startId）{
 //将一个childevent侦听器添加到firebase 
 Firebase myFirebaseRef = new Firebase （ FirebaseURL）; 
 myFirebaseRef.child（FIREBASE_LOCATION）。addValueEventListener（new ValueEventListener（）{
 $ b @Override 
 public void onDataChange（DataSnapshot snapshot）{
 //使用DataSnapshot说调用通知
 
 $ b $ @覆盖$ b $公共无效onCancelled（FirebaseError错误）{
 Log.e（读取失败：，error.getMessage （））; 
} 
}）; 
 
 
 $覆盖
 public void onCancelled（FirebaseError firebaseError）{
 Log.e（The read failed：，firebaseError.getMessage ））; 
} 
}）; 
 
 return START_STICKY; 
 
 
 $ b $ / code $ / $ p 
 
 
注册你的服务在Manifest  p> 
 
 
 < service android：name =。ChildEventListener/>开始你的服务，并听取childEvents，开始你的服务的地点/时间取决于你的聊天应用程序设计 
I am using Firebase for creating a small chat application. I want ChildEventListener to keep listening to the firebase database location though my app is in background or it is exited. Currently I am registering it and when my app exits or closed using finish(), after that none of my methods of ChildEventListener are getting called like onChildAdded or onChildChanged though I haven't called removeEventListener.I want ChildEventListener to be always running in background. Is there anyway of doing that?
 解决方案 
Use service to listen your ChildEventListener
    public class ChildEventListener extends Service {
        @Override
        public IBinder onBind(Intent intent) {
            return null;
        }
        @Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            //Adding a childevent listener to firebase                
            Firebase myFirebaseRef = new Firebase("FirebaseURL");
            myFirebaseRef.child("FIREBASE_LOCATION").addValueEventListener(new ValueEventListener() {

                @Override
                public void onDataChange(DataSnapshot snapshot) {
                    //Do something using DataSnapshot say call Notification
                }

                @Override
                public void onCancelled(FirebaseError error) {
                    Log.e("The read failed: ", error.getMessage());
                }
            });

          }

                @Override
                public void onCancelled(FirebaseError firebaseError) {
                    Log.e("The read failed: ", firebaseError.getMessage());
                }
            });

            return START_STICKY;
       }

  }
register your Service inside Manifest
    <service android:name=".ChildEventListener "/>
Start your Service and listen for childEvents, where/when to start your service is up to your chat app design
                        
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