关于Service的一些疑问

我现在做的一个程序有下载功能，下载是在service中去做的，为了跟Activity进行交互，我把service放到Application中：
public class FlyThemeApplication extends Application {

public static final String TAG_LOG = "FlyThemeApplication";

public FlyThemeDownloadService mDownloadService;

@Override
public void onCreate() {
    super.onCreate();
    Log.i(TAG_LOG, "FlyThemeApplication onCreate");

    Intent startServiceIntent = new Intent();
    startServiceIntent.setClass(this, FlyThemeDownloadService.class);
    startService(startServiceIntent);

    Log.i(TAG_LOG, "service.obj=" + mDownloadService);

}

然后在Service的onCreate方法中：mFlyThemApplication = (FlyThemeApplication) this.getApplication();
mFlyThemApplication.mDownloadService = this;

之后所有地方都是通过拿到Application，然后调用service中的方法：
mFlyThemeApplication.mDownloadService.startDownload(mFlyTheme);

请问这样做可行么？

http://bbs.csdn.net/topics/380078663