祝大家國慶節快樂

祝大家國慶節快樂

上面是用java的JFrame為基礎實現的效果，下面用面向對象的思考分析并實現此效果：

1)找對象

最開始鼠標點擊沖出來的白色圓點 Bullet
白色圓點爆炸成一片(包含很多小圓點)Piece
主程序類 Guoqing 繼承于 JPanel
程序初始化類執行類GuoqingStart 繼承于JFrame

2) 類的設計, 定義出 類屬性(數據模型)

比如

白色圓點類Bullet
|-- int x x坐標
|-- int y y坐標

3) 界面繪制(利用Java Swing API 繪制界面）

4) 功能算法設計

原則: 一切功能 都是方法: 動詞就是方法

實現策略: 將功能映射到數學模型, 研究數據的變化規律

比如白色圓點類Bullet與*Piece中各個小圓點的移動，其實都是坐標位置的變化

5) 事件綁定(利用Java Swing API 實現事件綁定)
比如鼠標點擊監聽事件

6)完整代碼

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class GuoqingStart extends JFrame {
    Guoqing gq;
    public static void main(String[] args) {
        new GuoqingStart();
    }
    public GuoqingStart() {
        gq=new Guoqing();
        this.addMouseListener(gq);
        this.add(gq);
        new Thread(gq).start();
        this.setTitle("國慶快樂");
        this.setLocation(100, 0);
        this.setSize(1000,700);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }
}

class Guoqing extends JPanel implements MouseListener,Runnable{
    Bullet bullet;
    Vector<Bullet> bullets;
    static Vector<Piece> pieces;
    int times=1;
    public Guoqing() {
        bullets=new Vector<Bullet>();
        pieces=new Vector<Piece>();
    }
    public void paint(Graphics g) {
        super.paint(g);
        times++;
        g.setColor(Color.black);
        g.fillRect(0, 0, 2000, 1000);
        g.setColor(Color.lightGray);
        for(int i=0;i<this.bullets.size();i++){
            Bullet b=this.bullets.get(i);
            if(b.isLive){
                b.move();
                g.fillOval(b.x,b.oldY, 15, 15);
            }
        }
        
        for(int i=0;i<this.pieces.size();i++){
            Piece b=this.pieces.get(i);
            if(b.isLive){
                if(b.color==0){
                    g.setColor(Color.red);
                }else if(b.color==1){
                    g.setColor(Color.blue);
                }else if(b.color==2){
                    g.setColor(Color.cyan);
                }else if(b.color==3){
                    g.setColor(Color.green);
                }else{
                    g.setColor(Color.gray);
                }
                if(times%3==0){
                    b.move();
                }
                g.fillOval((int)b.x, (int)b.y, (int)b.w, (int)b.h);
            }
            
        }
    }
    public void mousePressed(MouseEvent e) {
        bullet=new Bullet(e.getX(),e.getY());
        this.bullets.add(bullet);
    }
    public void mouseClicked(MouseEvent e) {}
    public void mouseReleased(MouseEvent e) {}
    public void mouseEntered(MouseEvent e) {}
    public void mouseExited(MouseEvent e) {}
    @Override
    public void run() {
        while(true){
            this.repaint();
            try {
                Thread.sleep(20);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}
class Piece{
    double x,y;
    double w=15;
    double h=15;
    double velocityX, velocityY;
    boolean isLive=true;
    int color=0;
    int times=1;
    public Piece(double x,double y,double velocity,double angle,int color) {
        this.x=x;
        this.y=y;
        this.color=color;
        velocityX = velocity * Math.cos(angle);
        velocityY = velocity * Math.sin(angle);
    }
    public void move(){
        velocityX *= 0.75;
        velocityY += 1.0;
        velocityY *= 0.75;
        
        y += velocityY;
        x += velocityX;
        
        times++;
        if(times%7==0){
            this.w-=2;
            this.h-=2;
            if(this.w<=4){
                Guoqing.pieces.remove(this);
            }
        }
    }
}
class Bullet{
    int x;
    int y;
    int oldY=700;
    boolean isLive=true;
    Piece piece;
    Random r=new Random(System.currentTimeMillis());
    public Bullet(int x, int y) {
        this.x = x;
        this.y = y;
    }
    public void move(){
        oldY-=8;
        if(oldY<=y){
            this.isLive=false;
            int color=r.nextInt(4);
            for(int i=0;i<200;i++){
                double angleXy = r.nextDouble() * 2 * Math.PI;
                double angleZ  = r.nextDouble() * 2 * Math.PI;
                double velocity = 72 * Math.cos(angleZ);
                piece=new Piece(x,oldY,velocity, angleXy,color);
                Guoqing.pieces.add(piece);
            }
        }
    }

}