java - Android通过Local Service向Activity发送数据

Question

我有一个可以接收 gcm 推送通知的应用程序。我还进行了检查，如果应用程序当前打开，则不会创建通知。在Android中，我的推送服务是否可以告诉当前 Activity (如果可用/已连接)，新通知已到达，用新内容刷新您的列表？如果这是可能的，我相信我在我的服务中使用 IBinders 的道路是正确的。问题是我对服务如何调用 Activity 感到困惑(我理解反之亦然)。如果有人可以提供帮助，请提前致谢!

只是为了清楚起见。我正在尝试告诉 Activity 有一条新的推送消息。

服务

public class LocalBinder extends Binder {
    GcmIntentService getService() {
        return GcmIntentService.this;
    }
}
@Override
public IBinder onBind(Intent intent) {
    return mBinder;
}
private final IBinder mBinder = new LocalBinder();

客户端( Activity )

 private ServiceConnection mConnection = new ServiceConnection() {
    public void onServiceConnected(ComponentName className, IBinder service) {
        // This is called when the connection with the service has been
        // established, giving us the service object we can use to
        // interact with the service.  Because we have bound to a explicit
        // service that we know is running in our own process, we can
        // cast its IBinder to a concrete class and directly access it.
        mBoundService = ((GcmIntentService.LocalBinder)service).getService();

        // Tell the user about this for our demo.
        Toast.makeText(MainActivity.this, "Connected", Toast.LENGTH_SHORT).show();
    }

    public void onServiceDisconnected(ComponentName className) {
        // This is called when the connection with the service has been
        // unexpectedly disconnected -- that is, its process crashed.
        // Because it is running in our same process, we should never
        // see this happen.
        mBoundService = null;
        Toast.makeText(MainActivity.this, "Disconnected",
                Toast.LENGTH_SHORT).show();
    }
};
void doBindService() {
    // Establish a connection with the service.  We use an explicit
    // class name because we want a specific service implementation that
    // we know will be running in our own process (and thus won't be
    // supporting component replacement by other applications).
    bindService(new Intent(MainActivity.this,
            GcmIntentService.class), mConnection, Context.BIND_AUTO_CREATE);
    mIsBound = true;
}

void doUnbindService() {
    if (mIsBound) {
        // Detach our existing connection.
        unbindService(mConnection);
        mIsBound = false;
    }
}

@Override
protected void onDestroy() {
    super.onDestroy();
    doUnbindService();
}

Answer 1

是的，这是可能的。

在您的服务类中有一个 YourActivity 类型的变量

MyActivity myActivity = null;

在您的 onServiceConnected 方法中，在服务上设置通过绑定(bind)器获取的 myActivity 变量。

mBoundService.myActivity = MyActivity.this; // or something similar

现在你的服务有一个指向你的 Activity 的指针!!!是啊!!

在您的 Activity 中，创建一个函数，该函数的主体应使用数据刷新 UI。

最后，当服务检测到新数据时，调用:

if (myActivity)
    myActivity.refreshMyData();

解绑时，记得将myActivity变量设置为null，否则前面的代码会失败。