Java（32）：内部类

package zzz;

import zzz.Circle.Draw;

public class innerClass {

    public static void main(String[] args) {
        
        Circle circle = new Circle(10);
//        成员内部类创建方式必须依靠外部类对象创建
//        方式1：
        Circle.Draw draw = circle.new Draw();
        System.out.println(draw);
        System.out.println(circle.new Draw());
//        方式2：
        Circle.Draw draw2 = circle.getDraw();
        System.out.println(draw2);
    }
}

//    外部类
class Circle {
    
    private Draw draw = null;
    private double radius = 0;
    public static int count = 1;
    public Circle(double radius) {
        this.radius = radius;
    }
    
    public Draw getDraw() {
        if (draw == null) {
            draw = new Draw();
        }
        return draw;
    }
    
//    成员内部类
    class Draw {
        public Draw() {
            
        }
        public void drawShape() {
            System.out.println("draw shape.");
            
            System.out.println(radius);
            System.out.println(count);
        }
    }
}

更多详细参考：https://www.cnblogs.com/dolphin0520/p/3811445.html

public class InnerclassDemo {
    public static void main(String[] args) {
        
        Person person = new Person();
        Person.Heart heart = person.new Heart();
        heart.jump();
        person.setLive(false);
        heart.jump();
    }
}

class Person {
    private boolean live = true;
    
    public void setLive(boolean live) {
        this.live = live;
    }
    
    public boolean isLive() {
        return live;
    }
    
    class Heart {
        public void jump() {
            if (live) {
                System.out.println("心脏在跳动...");
            }else {
                System.out.println("死亡了...");
            }
        }
    }
}

public class InnerclassDemo2 {
    public static void main(String[] args) {
        FlyAble flyAble = new FlyAble() {
            @Override
            public void fly() {
                System.out.println("起飞!");
            }
        };
        
        flyAble.fly();
    }
    
}


abstract class FlyAble {
    public abstract void fly();
}

参考：https://www.cnblogs.com/libinhong/p/10990602.html