Android中定義接口的用法

一、接口方法用於回調 (這裏定義接口是爲了使用其接口方法)：

public interface ICallback {  
  public void   func();  
}  
  
public class Caller {  
  ICallback callback;  
  public void doCallback() {  
    callback.func();  
  }  
  
  public void setCallback(ICallback callback) {  
    this.callback = callback;  
  }  
  
}  
  
public class MainClass {  
  public MainClass() {  
  }  
  
  public static void main(String[] args) {  
    Caller caller = new Caller();  
    caller.setCallback(new ICallback () {  
      public void func() {  
        System.out.println("dosth");  
      }  
    });  
    caller.doCallback();  
  }  
}

二、向上轉型

interface People{  
   void peopleList();  
}  
class Student implements People{  
   public void peopleList(){  
       System.out.println("I’m a student.")；  
  }  
}  
class Teacher implements People{  
   public void peopleList(){  
       System.out.println("I’m a teacher.");  
   }  
}  
public class Example{  
   public static void main(String args[]){  
       People a;             //聲明接口變量  
       a=new Student();      //實例化，接口變量中存放對象的引用  
       a.peopleList();        //接口回調  
       a=new Teacher();     //實例化，接口變量中存放對象的引用  
       a.peopleList();       //接口回調  
  }  
}  
運行結果：  
I’m a student.  
I’m a teacher.

三、常量接口（這裏不在講）