Java 传递参数-接口实现与实现接口的具体类的对象

考虑到OnCompleteListener是一个接口，OnCompleteListeneImpl是一个具体的类，如下所示

####OnCompleteListener接口#####

public interface OnCompleteListener {

    public void onComplete();
}

class OnCompleteListenerImpl  implements OnCompleteListener {
    public void onComplete() {    
        System.out.println("Yeah, the long running task has been completed!");
    }
}

longRunningTask.setOnCompleteListener(new OnCompleteListener() {

        @Override
        public void onComplete() {
            System.out.println("Yeah, the long running task has been completed!");
        }
    }
);

OnCompleteListenerImpl obj = new OnCompleteListenerImpl();

longRunningTask.setOnCompleteListener(obj);

#####OnCompleteListenerImpl####

public interface OnCompleteListener {

    public void onComplete();
}

class OnCompleteListenerImpl  implements OnCompleteListener {
    public void onComplete() {    
        System.out.println("Yeah, the long running task has been completed!");
    }
}

longRunningTask.setOnCompleteListener(new OnCompleteListener() {

        @Override
        public void onComplete() {
            System.out.println("Yeah, the long running task has been completed!");
        }
    }
);

OnCompleteListenerImpl obj = new OnCompleteListenerImpl();

longRunningTask.setOnCompleteListener(obj);

这是怎么回事

#####片段A####

public interface OnCompleteListener {

    public void onComplete();
}

class OnCompleteListenerImpl  implements OnCompleteListener {
    public void onComplete() {    
        System.out.println("Yeah, the long running task has been completed!");
    }
}

longRunningTask.setOnCompleteListener(new OnCompleteListener() {

        @Override
        public void onComplete() {
            System.out.println("Yeah, the long running task has been completed!");
        }
    }
);

OnCompleteListenerImpl obj = new OnCompleteListenerImpl();

longRunningTask.setOnCompleteListener(obj);

不同于

#####片段B#####

public interface OnCompleteListener {

    public void onComplete();
}

class OnCompleteListenerImpl  implements OnCompleteListener {
    public void onComplete() {    
        System.out.println("Yeah, the long running task has been completed!");
    }
}

longRunningTask.setOnCompleteListener(new OnCompleteListener() {

        @Override
        public void onComplete() {
            System.out.println("Yeah, the long running task has been completed!");
        }
    }
);

OnCompleteListenerImpl obj = new OnCompleteListenerImpl();

longRunningTask.setOnCompleteListener(obj);

---

这两种方法都很相似，但它们之间有很大的区别

可用性

public interface OnCompleteListener {

    public void onComplete();
}

class OnCompleteListenerImpl  implements OnCompleteListener {
    public void onComplete() {    
        System.out.println("Yeah, the long running task has been completed!");
    }
}

longRunningTask.setOnCompleteListener(new OnCompleteListener() {

        @Override
        public void onComplete() {
            System.out.println("Yeah, the long running task has been completed!");
        }
    }
);

OnCompleteListenerImpl obj = new OnCompleteListenerImpl();

longRunningTask.setOnCompleteListener(obj);

类OnCompleteListenerImpl是可重用的，您不需要在多个位置重写同一对象

初始化OnCompleteListenerImpl对象时需要小心，因为可以通过多种方式进行初始化，所以必须小心其范围

如果使用匿名方法，则无需创建新的实现类

---

总之，这两种方法都有不同的用例，您需要遵循哪种方法。对于干净的代码和可重用性，我们使用实现类，但对于安全和单实例使用，您可以使用匿名类方法。

这是相同的。如果您多次使用它，请选择OnCompleteListenerImpl解决方案。大致相同，尽管

Snippet A

正在创建一个匿名类，而不是命名类。。。。你可能想看看和