java - 如何在 android 中收到来自 firebase 的消息时创建事件监听器？

Question

我正在使用 firebase 接收消息。收到消息时 (onMessageReceived())。我想检查消息是否包含所需的字符串(比如“你好”)。如果是，我希望它被另一个 fragment 知道，这样 fragment 中的一些方法将根据消息被调用。

为此，我想在收到消息时创建事件监听器。在我的 fragment 中，将调用两个 API。 on API 将调用 onCreatedView()。基于来自 firebase 的消息，应该调用第二个 API。这两个 API 调用应在几分之一毫秒内完成。

MyFireBaseMessage.java

public class MyMessagingService extends FirebaseMessagingService {

@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    super.onMessageReceived(remoteMessage);
    Log.d("message here","message here "+ remoteMessage.getData().toString());
    String value = remoteMessage.getData().get("msg");
    Log.d("value here","value here"+" "+value);
    if (value.equalsIgnoreCase("hello"))
    {
        //implement custom event listener here
    }
}
}

Answer 1

我现在能想到的一种方法是使用 LocalBroadcast。做这个

1. 修改您的 Firebase 服务并放置此内容

   public class MyMessagingService extends FirebaseMessagingService {
   private LocalBroadcastManager broadcaster;
   
   @Override
   public void onCreate() {
       broadcaster = LocalBroadcastManager.getInstance(this);
   }
   
   
   @Override
   public void onMessageReceived(RemoteMessage remoteMessage) {
       super.onMessageReceived(remoteMessage);
       Log.d("message here", "message here " + remoteMessage.getData().toString());
       String value = remoteMessage.getData().get("msg");
       Log.d("value here", "value here" + " " + value);
       if (value.equalsIgnoreCase("hello")) {
           Intent intent = new Intent("custom-listener");
           broadcaster.sendBroadcast(intent)
       }
   }
   

2. 在 fragment 类中进行更改

公共(public)类 BlankFragment 扩展 fragment {

    Context context;
    BroadcastReceiver br;

    public BlankFragment() {
        // Required empty public constructor
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        this.context = context;
    }

    @Override
    public void onResume() {
        super.onResume();
        setup();
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        LocalBroadcastManager.getInstance(context).unregisterReceiver(mMessageReceiver);
    }

    private void setup() {
        LocalBroadcastManager.getInstance(context).registerReceiver(mMessageReceiver,
                new IntentFilter("custom-listener"));
    }


    private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            // Get extra data included in the Intent
            String message = intent.getStringExtra("message");
            Log.d("receiver", "Got message: " + message);
        }
    };

}

通过广播，您将能够收听您想要收听的 Activity 。当您的 if 条件为真时，将触发 Fragment 类中的 onReceive 方法，即 value.equalsIgnoreCase("hello")

对于此答案的格式，我们深表歉意。难以调整。