Android 本地服务示例、bindservice() 和 ServiceConnection()

Question

我有一个与此相关的问题 question @mnish 大约一年前问过这个问题。

请看一下他的问题和代码。他实现了一个 ServiceConnection() 并将其传递给 bindService()。这遵循 Service 中的本地服务示例靠近顶部的文档。

我想实现本地服务示例，因此我尝试添加来自@mnish 问题/答案的一些细节。在 ServiceConnection() @mnish 中有这一行让我感到困惑:

mService = ILocService.Stub.asInterface(iservice);

我知道 @mnish 写了这段代码，但是有没有人知道 ILocService 是什么以及我如何创建自己的 ILocService？这个构造在哪里记录，我需要它吗？另外，IBinder iservice 的值(value)从何而来？

Answer 1

他可能正在使用 Android 接口(interface)定义语言 (AIDL) http://developer.android.com/guide/components/aidl.html

因此，他必须像记录的那样使用服务器端实现的 stub :

 // 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.  We are communicating with our
 // service through an IDL interface, so get a client-side
 // representation of that from the raw service object.
 mService = IRemoteService.Stub.asInterface(service);

iservice 引用来自 onServiceConnected 方法，该方法在将服务绑定(bind)到您的 Activity 后调用。调用 bindService 传递给实现 onServiceConnected 方法的 ServiceConnection。

当您在本地实现服务时，您不需要“IRemoteService.Stub.asInterface(service)”，然后您可以将服务转换为本地服务。

本地服务示例在服务中执行此操作:

public class LocalService extends Service {
    private NotificationManager mNM;

    // Unique Identification Number for the Notification.
    // We use it on Notification start, and to cancel it.
    private int NOTIFICATION = R.string.local_service_started;

    /**
     * Class for clients to access.  Because we know this service always
     * runs in the same process as its clients, we don't need to deal with
     * IPC.
     */
    public class LocalBinder extends Binder {
        LocalService getService() {
        return LocalService.this;
        }
    }

    ...

}

在 ServiceConnection 类的 Activity 中:

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 = ((LocalService.LocalBinder)service).getService();

        // Tell the user about this for our demo.
        Toast.makeText(Binding.this, R.string.local_service_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(Binding.this, R.string.local_service_disconnected,
            Toast.LENGTH_SHORT).show();
    }
};