1.中介者模式的定义及使用场景

定义：

使用场景：

当对象之间的交互操作很多且每个对象的行为操作都彼此依赖时，为防止在修改一个对象的行为时，同时涉及修改很多其他对象的行为，可采用中介者模式，来解决紧耦合问题。该模式将对象之间的多对多关系变成一对多关系，中介者对象将系统从网状结构变成以调停者为中心的星形结构，达到降低系统的复杂性，提高可扩展的作用。

2.中介者模式的优缺点

2.1优点

2.2缺点

3.注意实现

4.中介者模式的实现方式

public abstract class Colleague {    Mediator mediator;    public Colleague(Mediator mediator) {        this.mediator = mediator;    }    public abstract void action();}
public class ConcreteColleagueA extends Colleague {    public ConcreteColleagueA(Mediator mediator) {        super(mediator);    }    @Override    public void action() {        System.out.PRintln("ColleagueA do action!");    }    public void doPrivateA() {        System.out.println("ColleagueA do private!");    }}
public class ConcreteColleagueB extends Colleague {    public ConcreteColleagueB(Mediator mediator) {        super(mediator);    }    @Override    public void action() {        System.out.println("ColleagueB do action!");    }    public void doPrivateB() {        System.out.println("ColleagueB do private!");    }}
 public abstract class Mediator {    protected ConcreteColleagueA concreteColleagueA;    protected  ConcreteColleagueB concreteColleagueB;    public abstract void method();    public void setConcreteColleagueA(ConcreteColleagueA concreteColleagueA) {        this.concreteColleagueA = concreteColleagueA;    }    public void setConcreteColleagueB(ConcreteColleagueB concreteColleagueB) {        this.concreteColleagueB = concreteColleagueB;    }}
public class ConcreteMediator extends Mediator {    @Override    public void method() {        concreteColleagueA.action();        concreteColleagueB.action();        concreteColleagueA.doPrivateA();        concreteColleagueB.doPrivateB();    }}
5.中介者模式在Android中的实际应用
Android的Activity实际就是一个中介者模式，形形式式的View交互都在Activity中统一执行，View之间彼此不交互。