为什么getActiveNotifications（）返回Null？怎么了？

问题描述

大家好，

在Android中学习通知，并且想知道为什么这段代码无效......而不是它的返回Null？



这段代码片段来自我的MainActivity，

NotificationService是我的公共类，它扩展了NotificationListenerService

i还在Manifest中为我的应用程序发出了必要的权限来观看通知！

 受保护  void  onCreate（Bundle savedInstanceState）{
  super  .onCreate（savedInstanceState）; 
 setContentView（R.layout.activity_main）; 
 
 NotificationService ns =  new  NotificationService（）; 
 StatusBarNotification [] sbn = ns.getActiveNotifications（）; 
 
  if （sbn！= null）
 {
 Log.i（  XXXXXX， 长度： + sbn.length）; 
} 
  else  
 {
 Log.i（  XXXXXX，  Null ）; 
} 
 
} 

我想把NotificationListenerService里面的getActiveNotifications（）转到在我启动我的应用程序之前，返回状态栏中已经存在的通知数组...所以在我启动应用程序并且OnCreate被解雇后...即使有4个当前通知我仍然会得到Null？

解决方案

hi guys,
was learning notifications in Android and was wonderring why was this code not working... instead its returning Null?

This code snippet is from my MainActivity ,
NotificationService is my public class that extends NotificationListenerService
i have also made the necessary permissions in the Manifest for my app to watch notifications!

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

NotificationService ns = new NotificationService();
StatusBarNotification[] sbn = ns.getActiveNotifications();

        if (sbn != null)
        	{
        	Log.i("XXXXXX", "Lenght: " + sbn.length);
        	}
        else
        	{
        	Log.i("XXXXXX", "Null" );
        	}

    }

I am trying to get the getActiveNotifications() inside the NotificationListenerService to return me an array of the Notifications that are already present in the statusbar before i had launched my app... so after i have launched the app and the OnCreate is fired... i still get Null even though there are 4 current notifications?

解决方案

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