如何在没有Activity的情况下使用LocalBroadcastManager [英] How to use LocalBroadcastManager without Activity

问题描述

我通过扩展 BroadcastReceiver 来获得我的班级 ABC 。但最近，我偶然发现了 LocalBroadcastManager 。

这是我的班级声明：

  public class ABC extends BroadcastReceiver {} 
  

因此，ABC作为监听器工作，并根据它将调用另一个对象的操作。 / p>

我到处检查是否可以在没有活动的情况下使用 LocalBroadcastManager 。实际上，ABC类是一个核心应用程序类，它不连接到任何UI组件。

让我知道如何在我的场景中使用 LocalBroadcastManager 。

我是Android新手。请帮忙。

解决方案

也许答案有点晚了但我希望它对你有用。

第一步是有一个扩展应用程序的类。这将用于从Activity外部获取应用程序上下文。

  public class AppContext extends Application {
 
 private static AppContext实例; 
 
 public AppContext（）{
 instance = this; 
} 
 
 public static Context getContext（）{
 return instance; 
} 
} 
  

然后将以下代码添加到您想要的位置将消息发送到LocalBroadcasr

  Intent intent = new Intent（intent-filter）; 
 intent.putExtra（message，your-message-here）; 
 LocalBroadcastManager.getInstance（AppContext.getContext（））。sendBroadcast（intent）; 
  

最后，你的班级ABC会收到这个意图，因为我向你显示下一个

 私有BroadcastReceiver接收器; 
 
公共类ABC {
 
 public ABC（）{
 receiver = new BroadcastReceiver（）{
 
 @Override 
 public void onReceive（Context context，Intent intent）{
 //在这里接收你的消息
 String message = intent.getStringExtra（message）; 
}; 
 LocalBroadcastManager.getInstance（AppContext.getContext（））。registerReceiver（receiver，new IntentFilter（intent-filter））; 
} 
  

I had my class 'ABC' by extending the BroadcastReceiver. But recently, I stumbled upon LocalBroadcastManager.

here is my class declaration:

public class ABC extends BroadcastReceiver {}

So ABC is working as the listener and based on the action it would call another object.

I checked everywhere whether I can use LocalBroadcastManager here without an activity. Actually class ABC is a core application class where it doesn't connect to any UI component.

Let me know how can I use LocalBroadcastManager in my scenario.
I'm new to Android. Please help.

解决方案

Maybe it's a bit late for the answer but I hope it'd be useful to you.

The first step is having a class which extends the application. This will be used to get the application context from outside an Activity.

public class AppContext extends Application {

    private static AppContext instance;

    public AppContext() {
      instance = this;
    }

    public static Context getContext() {
      return instance;
    }
}

Then add the following piece of code where you want to send the message to LocalBroadcasr

Intent intent = new Intent("intent-filter");
intent.putExtra("message", "your-message-here");
LocalBroadcastManager.getInstance(AppContext.getContext()).sendBroadcast(intent);

Finally, your class ABC will receive this intent as I show you next

private BroadcastReceiver receiver;

public class ABC{

public ABC(){
    receiver = new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {
      //receive your message here
      String message = intent.getStringExtra("message");
    };
        LocalBroadcastManager.getInstance(AppContext.getContext()).registerReceiver(receiver, new IntentFilter("intent-filter")); 
}

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