服务端如何暴露IBinder接口对象：

package com.example.mydownload;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;

public class MyService extends Service {

	//接口对象
	private IBinder mybBinder = new MyBinder();
	
	//实现接口中的方法
	private class MyBinder extends Binder{
		public String helloWorld(){
			return "hello!";
		}
	}
	@Override
	public IBinder onBind(Intent arg0) {
		// TODO Auto-generated method stub
		return mybBinder;
	}


}