android中常见的回调模式

最近做ListView网络图片的异步加载,以及下载网路MP3动态进度显示。看过一些源码都涉及这样的回调,这样节省了很多不必要的重复操作,非常简便。写了一个Demo,够简单的吧.
Demo1.java

package com.demo;   
import com.demo.Demo2.TestInterface;   
public class Demo1 {   
  
    private String demo2Param;   
    private Demo2 demo2 = new Demo2();   
       
    public void demo1Test(){   
        demo2.demo2Test(new TestInterface() {   
            public void method(String para1, String para2) {   
                // TODO Auto-generated method stub   
                demo2Param = para1 + " && "+para2;   
                System.out.println("Print:"+demo2Param);   
            }   
        });   
    }   
       
    public static void main(String[] args) {   
        new Demo1().demo1Test();   
    }   
}  

Demo2.java

package com.demo;   
public class Demo2 {   
       
    private String para1 = "IS PARA1";   
    private String para2 = "IS PARA2";   
       
    public void demo2Test(TestInterface testInterface){   
        testInterface.method(para1,para2);   
    }   
       
    public interface TestInterface{   
        public void method(String para1,String para2);   
    }   
}