java - Activity 与 GCMListenerService Android 通信

Question

我正在使用 GCM 开发具有推送通知功能的 Android 应用程序。我创建了一个名为 PushNotificationService 的类，它扩展了 GCMListenerService。在 onMessageReceived(String from, Bundle data) 中，我能够在推送通知中获取消息。

现在，每当在推送中收到特定消息时，我想访问我的 MainActivity 类中的一个方法。

下面是我的代码:-

PushNotificationService.java

public class PushNotificationService extends GcmListenerService {

@Override
    public void onMessageReceived(String from, Bundle data) {
        // TODO Auto-generated method stub
        super.onMessageReceived(from, data);



         String message = data.getString("message");

         if(message.equalsIgnoreCase("Begin Task"))
            {

                    //call method from MainActivity.class

            }

        }
}

MainActivty.java

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    public void beginTask()

    {

        Log.d("GCM","Message Received from Server");
        finish();

    }
}

我希望在收到消息“开始任务”时执行 beginTask() 方法。

我知道一种方法是通过 Service->Interface->Activity 架构，但我无法使用它，因为我从未创建 PushNotificationService 的对象。

请帮忙。

更新:-我现在正在使用 Otto Library，下面是我的代码。

添加了新的MyBus.java

public class MyBus extends Bus {
    private static Bus bus;
    //isRegistered is used to track the current registration status
    private static boolean isRegistered;
    private Handler handler = new Handler(Looper.getMainLooper());

    public MyBus() {
        if (bus == null) {
            //ANY will allow event bus to run even with services
            //and broadcast receivers
            bus = new Bus(ThreadEnforcer.ANY);
        }
    }

    @Override
    public void register(Object obj) {
        //The bus is registered when an activity starts
        bus.register(obj);
        isRegistered = true;
    }

    @Override
    public void unregister(Object obj) {
        //The bus is unregistered when an activity goes to background
        bus.unregister(obj);
        isRegistered = false;
    }

    @Override
    public void post(final Object event) {
        if (Looper.myLooper() == Looper.getMainLooper()) {
            //post the event in main thread or background thread
            bus.post(event);
        } else {
            handler.post(new Runnable() {
                @Override
                public void run() {
                    bus.post(event);
                }
            });
        }
    }

    public boolean isRegistered(){
        return isRegistered;
    }
}

PushNotificationService.java

public class PushNotificationService extends GcmListenerService {

@Override
    public void onMessageReceived(String from, Bundle data) {
        // TODO Auto-generated method stub
        super.onMessageReceived(from, data);

        MyBus myBus = new MyBus();
        myBus.register(myBus);

         String message = data.getString("message");

         if(message.equalsIgnoreCase("Begin Task"))
            {

                    myBus.post(message);

            }

        }
}

MainActivity.java

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    @Subscribe
    public void beginTask()

    {

        Log.d("GCM","Message Received from Server");


    }
}

问题还是没有解决。 MainActivity.java 中的 beginTask() 仍未被调用。

Answer 1

使用 eventBus 库来促进这个过程...

我在这个过程中使用 Otto http://square.github.io/otto/
这是另一个 eventBus 库 https://greenrobot.github.io/EventBus/

步骤:
1.从服务创建一个事件
2.在 Activity 中添加监听器
3.如果 Activity 正在运行，将执行该方法

**编辑 1:**
我已经像这样抽象了奥托巴士。

package com.mypackage.eventBus;

import android.os.Handler;
import android.os.Looper;

import com.squareup.otto.Bus;
import com.squareup.otto.ThreadEnforcer;

/**
 * Created by gowtham on 10/6/15.
 */
public class MyBus extends Bus {
    private static Bus bus;
    //isRegistered is used to track the current registration status
    private static boolean isRegistered;
    private Handler handler = new Handler(Looper.getMainLooper());

    public MyBus() {
        if (bus == null) {
            //ANY will allow event bus to run even with services
            //and broadcast receivers
            bus = new Bus(ThreadEnforcer.ANY);
        }
    }

    @Override
    public void register(Object obj) {
        //The bus is registered when an activity starts
        bus.register(obj);
        isRegistered = true;
    }

    @Override
    public void unregister(Object obj) {
        //The bus is unregistered when an activity goes to background
        bus.unregister(obj);
        isRegistered = false;
    }

    @Override
    public void post(final Object event) {
        if (Looper.myLooper() == Looper.getMainLooper()) {
            //post the event in main thread or background thread
            bus.post(event);
        } else {
            handler.post(new Runnable() {
                @Override
                public void run() {
                    bus.post(event);
                }
            });
        }
    }

    public boolean isRegistered(){
        return isRegistered;
    }
}

创建上述对象的实例并尝试发布事件

EDIT 2 用于 Jcarlo 的评论
按照以下步骤查找 Activity 的状态。

1. 在您的 Activity 的 onResume 中调用 MyBus.getInstance().register(this)。
2. 在您的 Activity 的 onPause 调用 MyBus.getInstance().unregister(this)。

3. 在发布消息之前在您的 GCM IntentService 中

   if(MyBus.getInstance().isRegistered()){ //应用程序还活着 //发布数据 }别的{ //显示通知

希望对你有帮助