JAVA基础——回调实现方式

原理就不讲了，这里只记录几种写法的demo：

1. interface，回调函数在A里实现

A.java

public class A {    public static void main(String[] args) {        B b = new B();        b.setBListener(new IB() {            @Override            public void onSuccess(String message) {                System.out.println("A里定义onSuccess,meesage="+message);            }            @Override            public void onError(String error) {                System.out.println("A里定义onError,error="+error);            }        });        b.start(true);        b.start(false);    }}

IB.java

public interface IB{    public void onError(String error);    public void onSuccess(String message);}

B.java

public class B  {    private IB b;    public void setBListener(IB b) {        this.b = b;    }    public void start(boolean input){        if(input)            b.onSuccess("YES");        else            b.onError("NO");    }}

2. interface的一般用法，不是回调

A.java

public class A {    public static void main(String[] args) {        B b = new BImpl();        b.onSuccess("A里调用onSuccess");        b.onError("A里调用onError");    }}

B.java

public interface B{    void onError(String error);    void onSuccess(String message);}

BImpl.java

public class BImpl implements B{    @Override    public void onError(String error) {        System.out.println("运行B里定义的onError，打印参数：" + error);    }    @Override    public void onSuccess(String message) {        System.out.println("运行B里定义的onSuccess，打印参数：" + message);    }}

3. abstract

A.java

public class A {    public static void main(String[] args) {        B b = new B();        b.start(new Callback() {            @Override            public void success(String message) {                System.out.println("定义在A里的 success，参数值：" + message);                //super.success(message);            }            @Override            public void error(String err) {                System.out.println("定义在A里的 error，参数值：" + err);                //super.error(err);            }        });    }}

B.java

public class B{       public void start(final Callback callback) {           callback.success("YES");           callback.error("NO");       }}

Callback.java

public abstract class Callback {    public void success(String successMsg) {}    public void error(String exceptionMsg) {}}