当Activity在后台时如何接收事件总线事件 [英] How to receive eventbus events when Activity is in the background

问题描述

我想使用Firebase通知服务获取通知消息.我正在从Firebase发送消息，没关系.

I want to get notification message using Firebase Notification service. I'm sending message from Firebase, it is ok.

如果用户在MainActivity中运行，我想获得此通知，我也想使用对话框显示弹出窗口.

I want to get this notification if user run in MainActivity also I want to show pop-up using dialog.

如果用户运行其他活动(例如SettingActivity或ProfileActivity)，则无论如何都会有通知句柄，并且用户运行MainActivity的弹出窗口会突然出现.

If user run other activities for example SettingActivity or ProfileActivity, notification handle anyway and user run MainActivity pop-up appear suddenly.

为此，我正在使用Greenbot Eventbus.当我进入MainActivity并收到通知时，它就可以了.但是当我进入另一个Activity通知时，不会出现.

To do this I'm using Greenbot Eventbus. When I'm inside MainActivity and notification comes It appears so it is ok. But When I'm inside another Activity notification not coming.

在MainActivity出现之前如何处理此消息?

How to handle this message until come MainActivity?

public class NotificationService  extends FirebaseMessagingService {
    private static final String TAG = "evenBus" ;

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);


        Log.d(TAG, "onMessageReceived");
        // Check if message contains a notification payload.
        if (remoteMessage.getNotification() != null) {
            // do nothing if Notification message is received
            Log.d(TAG, "Message data payload: " + remoteMessage.getNotification().getBody());
            String body = remoteMessage.getNotification().getBody();
            EventBus.getDefault().post(new NotificationEvent(body));
        }
    }
}

MainActiviy

MainActiviy

@Override
    protected void onResume(){
       EventBus.getDefault().register(this);
 }

// This method will be called when a MessageEvent is posted (in the UI thread for Toast)
@Subscribe(threadMode = ThreadMode.MAIN)
public void onMessageEvent(NotificationEvent event) {
    Log.v("onMessageEvent","Run");
    Toast.makeText(MainActivity.this, event.getBody(), Toast.LENGTH_SHORT).show();
    alertSendActivity("title",event.getBody());
}

@TargetApi(11)
protected void alertSendActivity(final String title,final String data) {
    alt = new AlertDialog.Builder(this,
            AlertDialog.THEME_DEVICE_DEFAULT_LIGHT).create();
    alt.setTitle(title);
    alt.setMessage(data);
    alt.setCanceledOnTouchOutside(false);
    alt.setCancelable(false);
    alt.setButton(AlertDialog.BUTTON_NEUTRAL, getString(R.string.ok),
            new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface arg0, int arg1) {
                    alt.dismiss();
                }
            });

    alt.show();
}

protected void onStop() {
    super.onStop();
     EventBus.getDefault().unregister(this);
}

推荐答案

您正在onStop()中调用unregister()，因此当MainActivity在后台时您不会收到事件.

You're calling unregister() in onStop(), so you do not receive events when MainActivity is in the background.

要接收事件，即使Activity在后台，也应在onCreate()中注册，然后在onDestroy()中注销(而不是在onResume()/onStop()中).

To receive events even when the Activity is in the background, you should register in onCreate() and unregister in onDestroy() (rather than in onResume()/onStop()).

将以下行移动到onCreate():

EventBus.getDefault().register(this);

然后将其发送到onDestroy():

EventBus.getDefault().unregister(this);

还请查看活动生命周期.

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