1.中介者模式的定義及使用場景

定義：

使用場景：

當對象之間的交互操作很多且每個對象的行為操作都彼此依賴時，為防止在修改一個對象的行為時，同時涉及修改很多其他對象的行為，可采用中介者模式，來解決緊耦合問題。該模式將對象之間的多對多關系變成一對多關系，中介者對象將系統從網狀結構變成以調停者為中心的星形結構，達到降低系統的復雜性，提高可擴展的作用。

2.中介者模式的優缺點

2.1優點

2.2缺點

3.注意實現

4.中介者模式的實現方式

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中的實際應用
Android的Activity實際就是一個中介者模式，形形式式的View交互都在Activity中統一執行，View之間彼此不交互。