android – 远程服务如何将消息发送到绑定的Activity？

使用服务与活动进行通信涉及创建可以从活动传递到服务的侦听器.

您需要创建绑定到活动的服务.

第一步是提供服务.在服务中,确保您有一个Binder对象和返回绑定对象的方法.下面是我在我的服务中用来检索我的活页夹的示例.另请注意,此绑定程序有一个设置侦听器的方法,该侦听器将作为BoundServiceListener类型字段保存在服务中.

/**
 * Class used for the client Binder.  Because we kNow this service always
 * runs in the same process as its clients,we don't need to deal with IPC.
 */
public class DownloadBgBinder extends Binder {

    public DownloadBgService getService() {
        // Return this instance of LocalService so clients can call public methods
        return DownloadBgService.this;
    }

    public void setListener(BoundServiceListener listener) {
        mListener = listener;
    }
}

@Override
public IBinder onBind(Intent intent) {
    return mBinder;
}

现在,您需要创建某种接口,您可以将其传递给服务可用于发送更新的binder对象.下面是我的BoundServiceListener.

public interface BoundServiceListener {

    public void sendProgress(double progress);
    public void finishedDownloading();
}

现在,在您的活动中,您需要创建一个用于绑定到服务的ServiceConnection对象.所以添加这样的东西.

/** Defines callbacks for service binding,passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {

    @Override
    public void onServicedisconnected(ComponentName arg0) {
        mBound = false;
    }

    @Override
    public void onServiceConnected(ComponentName name,IBinder service) {
        // We've bound to LocalService,cast the IBinder and get LocalService instance
        DownloadBgBinder binder = (DownloadBgBinder) service;
        mService = binder.getService();
        binder.setListener(new BoundServiceListener() {

            @Override
            public void sendProgress(double progress) {
                // Use this method to update our download progress
            }

            @Override
            public void finishedDownloading() {

            }   
        });

        mBound = true;
    }

现在要注意的关键是

binder.setListener(new BoundServiceListener() {

    @Override
    public void sendProgress(double progress) {
        // Use this method to update our download progress
    }

    @Override
    public void finishedDownloading() {

    }
});

这部分是我实际将BoundServiceListener接口发送到服务类的地方.然后,服务类在此处使用该侦听器对象

if (mListener!=null)
        mListener.finishedDownloading();
    if (mListener!=null)
        mListener.sendProgress(percent);

现在,您可以将它放在服务类中的任何位置,您的活动将收到进度更新.

还要确保在您的活动中包含以下内容以实际绑定和启动服务.

Intent intent = new Intent(this,DownloadBgService.class);
startService(intent);
bindService(intent,mConnection,Context.BIND_AUTO_CREATE);

请记住,即使您绑定到服务,它也不会实际启动,直到您调用启动服务.绑定到服务只是将服务连接到活动. startService()方法调用服务

onStartCommand(Intent intent,int flags,int startId)

同时在清单中声明您的服务

<service android:name=".services.DownloadBgService" />

在活动离开时也取消绑定服务

@Override
protected void onStop() {
    super.onStop();
    // Unbind from the service
    if (mBound) {
        unbindService(mConnection);
        mBound = false;
    }
}

希望这可以帮助.