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) {}
}