package cn.feike.shoot; import java.awt.Graphics; import java.awt.image.BufferedImage; public abstract class FlyingObject { protected double x;//物体的x坐标 protected double y;//物体的y坐标 protected double width;//物体的宽 protected double heigth;//物体的高 protected BufferedImage image;//当前正在显示的图片 protected int index = 0;//图片数组下标序号,子类中使用 protected double step;//飞行物每次(1/24秒)移动的距离 protected int life;//命 protected int state;//飞行物的状态 public static final int ACTIVE=0;//活着状态 public static final int DEAD=1;//死亡状态 public static final int REMOVE=2;//回收状态 //默认构造器 public FlyingObject() { life = 1; state = ACTIVE; } //有参构造器 public FlyingObject(double width,double heigth){ this();//调用无参数的构造器,必须写在第一行. this.x = (int)(Math.random()*(480-width)); this.y = -heigth; this.width = width; this.heigth = heigth; step = Math.random()*3+0.8;//初始化step为[0.8,3.8)之间的数 } //重写toString方法 public String toString() { return x+","+y+","+width+","+heigth+","+image; } //重写paint,方便子类对象的使用 public void paint(Graphics g) { g.drawImage(image, (int)x, (int)y, null);//绘制图片 } //飞行物移动的move方法 public void move(){ if(state == ACTIVE){ y += step; return ; } if(state == DEAD){ //从子类对象中获取下一张照片 BufferedImage img = nextImage(); if(img == null){ state = REMOVE;//没有照片则回收 }else{ image = img;//否则把子类的图片传给image } //越界则销毁 if(y>=825){ state = REMOVE; } } } protected abstract BufferedImage nextImage(); public void hit(){ if(life>0){ life--; } if(life==0){ state = DEAD; } } public boolean duang(FlyingObject obj){ //this(x,y,w,h) //obj(x,y,w,h) double x1 = this.x - obj.width; double x2 = this.x + this.width; double y1 = this.y - obj.width; double y2 = this.y + this.heigth; return x1<obj.x&&obj;.x<x2&&y1;<obj.y&&obj;.y<y2; } public boolean isDead(){ return state == DEAD; } public boolean isActive(){ return state == ACTIVE; } public boolean canRemove(){ return state == REMOVE; } public void goDead(){ if(isActive()){ state = DEAD; } }