一.接口的使用
- interface implements
package Day12_14_01;
/*
* 接口的三个关键点:
* 1.接口代表能力（实现了接口就表示拥有了该接口的能力（方法））
* 2.接口代表约定（实现某接口之后必须要将接口的所有方法重写，否则必须声明该类为抽象类）
* 3.接口代表角色（实现了接口 就扮演了该接口所表示的角色）
*
* 接口之间允许相互继承的，而且支持多重继承（一个接口继承多个接口）
*
*
*/
public class FatherTest
{
public static void main(String[] args)
{
Son son =new Son("小明");
son.gamble();
son.smoke();
son.chant();
son.eatVegetable();
son.knockTheBell();
son.playPiano();
son.playViolin();
// 抽象类和接口本身不能实例化，但是可以使用就地实例化的方式来创建对象
// 所谓就地实例化就是创建了一个匿名内部类（anonymous inner type）的对象
Musician musician=new Musician()
{
@Override
public void playViolin()
{
// TODO Auto-generated method stub
}
@Override
public void playPiano()
{
// TODO Auto-generated method stub
}
};
Father father=son;
father.gamble();
//father.smoke();当son赋值给father后，因为father指定了是Father类型，
//因此son不再具有Son的行为 ，也就是son会损失Son里面的行为，不在具有somke（）行为
Monk monk =son;
monk.chant();
//同理，将son赋值给monk，因为monk指定为Monk类，所以只能有Monk接口的方法
//Musician musician=son也如此
}
}```
package Day12_14_01;
public class Father
{
public String name;
public Father(String name)
{
this.name= name;
}
public void gamble()
{
System.out.println(this.name+"正在赌博!");
}
public void smoke()
{
System.out.println(this.name+"会抽烟");
}
}
package Day12_14_01;
public class Son extends Father implements Monk,Musician
{
public Son(String name)
{
super(name);
}
public void smoke()
{
System.out.println(this.name+"会抽烟");
}
@Override
public void chant()
{
System.out.println(name+"念经");
}
@Override
public void eatVegetable()
{
System.out.println(this.name+"吃斋");
}
@Override
public void knockTheBell()
{
System.out.println(name+"撞钟");
}
@Override
public void playPiano()
{
System.out.println(name+"弹钢琴");
}
@Override
public void playViolin()
{
System.out.println(name+"拉小提琴");
}
}
package Day12_14_01;
public interface Monk
{
public void chant();
public void eatVegetable();
public void knockTheBell();
}
package Day12_14_01;
public interface Musician
{
public void playPiano();
public void playViolin();
}
#二.球球案例
- 适配器和lanmda表示的使用（java8新特性）
package Day12_14_02;
public class MeFrameTest
{
public static void main(String[] args)
{
new MeFrame().setVisible(true);
}
}
package Day12_14_02;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.Timer;
@SuppressWarnings("serial")
public class MeFrame extends JFrame
{
private BufferedImage image = new BufferedImage(800, 600, 1);
private Ball[] ballaArray = new Ball[100];
private int total = 0;
public MeFrame()
{
this.setTitle("小球");
this.setSize(800, 600);
this.setLocationRelativeTo(null);
this.setResizable(false);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.addMouseListener(new MouseAdapter()
{
@Override
public void mousePressed(MouseEvent e)
{
if (total < ballaArray.length)
{
int x = e.getX();
int y = e.getY();
int size =CommonUtil.randomInt(20, 100);
int sx = CommonUtil.randomInt(-10, 10);
int sy = CommonUtil.randomInt(-10, 10);
Color color =CommonUtil.RandomColor();
Ball ball = new Ball(x, y, size, color, sx, sy);
ballaArray[total] = ball;
total++;
}
}
});
Timer timer = new Timer(10, e ->
{
for (int i = 0; i < total; i++)
{
ballaArray[i].move();
}
repaint();
});
timer.start();
}
public void paint(Graphics g)
{
Graphics otherGrephics = image.getGraphics();
super.paint(otherGrephics);
for (int i = 0; i < total; i++)
{
ballaArray[i].draw(otherGrephics);
}
g.drawImage(image, 0, 0, null);
}
}
package Day12_14_02;
import java.awt.Color;
import java.awt.Graphics;
public class Ball
{
private int y;
private int size;
private Color color;
private int sx;
private int sy;
private int x;
public Ball(int x, int y, int size, Color color, int sx, int sy)
{
super();
this.x = x;
this.y = y;
this.size = size;
this.color = color;
this.sx = sx;
this.sy = sy;
}
public void move()
{
x+=sx;
y+=sy;
if(x<0||x>800-size)
{
sx=-sx;
}
if(y<30||y>600-size)
{
sy=-sy;
}
}
public void draw(Graphics g)
{
g.setColor(color);
g.fillOval(x, y, size, size);
}
}
#三.创建一个属于自己的工具类
package Day12_14_02;
import java.awt.Color;
/*
写一个工具类的要点：
1.所有方法都应该是静态方法
2.将构造器私有，不允许调用构造器创建对象
-
3.工具类一般不会被继承，所以是final的
*/
public final class CommonUtil
{
private CommonUtil()
{
//防止内部调用构造器创建对象
throw new AssertionError();
}public static int randomInt(int min,int max)
{
return (int) (Math.random()*(max-min+1)+min);
}public static Color RandomColor()
{
return new Color(randomInt(0, 255), randomInt(0, 255), randomInt(0, 55));
}
}