Android中定义接口的用法

1、接口方法用于回调 (这里定义接口是为了使用其接口方法)：

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();    }  }

2、向上转型

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;             //声明接口变量         a=new Student();      //实例化，接口变量中存放对象的引用         a.peopleList();        //接口回调         a=new Teacher();     //实例化，接口变量中存放对象的引用         a.peopleList();       //接口回调    }  }