tank/src/com/msb/TankFrame.java

package com.msb;

import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

/**
 * @Author bingor
 * @Date 2022-09-29 16:24
 * @Description: com.msb
 * @Version: 1.0
 */
public class TankFrame extends Frame {

    Tank myTank = new Tank(100, 500, DirEnum.RIGHT, GroupEnum.GOOD, this);
//    Explode explode = new Explode(100, 100, this);
//    Bullet bullet = new Bullet(200, 200, DirEnum.DOWN);
    List<Bullet> bullets = new ArrayList<>();
    List<Tank> tanks = new ArrayList<>();   //敌方坦克
    List<Explode> explodes = new ArrayList<>();     //爆炸效果
    public static final int GAME_WIDTH = 1000;
    public static final int GAME_HEIGHT = 800;

    public TankFrame() {

        setTitle("Tank war");
        setSize(GAME_WIDTH, GAME_HEIGHT);
        setResizable(true);
        setVisible(true);
        setBackground(Color.BLACK);

        addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                super.windowClosing(e);
                System.exit(0);
            }
        });

        addKeyListener(new MyKeyListener());

    }

    @Override
    public void paint(Graphics g) {
//        super.paint(g);
        Color color = g.getColor();
        g.setColor(Color.WHITE);
        g.drawString("子弹的数量：" + bullets.size(), 10, 60);
        g.drawString("敌方坦克数量：" + tanks.size(), 10, 90);
        g.drawString("爆炸的数量：" + explodes.size(), 10, 120);
        g.setColor(color);
        myTank.paint(g);

//        explode.paint(g);

        //画出敌方坦克
        for (int i=0; i<tanks.size(); i++) {
            tanks.get(i).paint(g);
        }

        for (int i=0; i<bullets.size(); i++) {
            bullets.get(i).paint(g);
        }

        for (int i=0; i<bullets.size(); i++) {
            for (int j=0; j<tanks.size(); j++) {
                bullets.get(i).collide(tanks.get(j));
            }
        }

        //爆炸效果
        for (int i=0; i<explodes.size(); i++) {
            explodes.get(i).paint(g);
        }

    }

    //双缓冲，解决闪烁现象
    Image offScreenImage = null;
    @Override   //在paint方法之前会被调用，但是我做实验了，闪烁现象似乎还是存在
    public void update(Graphics g) {
//        super.update(g);
        if(Objects.isNull(offScreenImage)) {
            offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT);
        }
        Graphics gOffScreen = offScreenImage.getGraphics();
        Color color = gOffScreen.getColor();
        gOffScreen.setColor(Color.BLACK);
        gOffScreen.fillRect(0, 0, GAME_WIDTH, GAME_HEIGHT);
        gOffScreen.setColor(color);
        paint(gOffScreen);
        g.drawImage(offScreenImage, 0, 0, null);
    }

    //这里使用内部内的原因是，只有TankFrame用到
    class MyKeyListener extends KeyAdapter {

        private boolean bL = false;
        private boolean bR = false;
        private boolean bU = false;
        private boolean bD = false;

        @Override
        public void keyPressed(KeyEvent e) {
            super.keyPressed(e);
            switch (e.getKeyCode()) {
                case KeyEvent.VK_LEFT : bL = true; break;
                case KeyEvent.VK_RIGHT : bR = true; break;
                case KeyEvent.VK_UP : bU = true; break;
                case KeyEvent.VK_DOWN : bD = true; break;
                default: break;
            }
            setDir();
        }

        @Override
        public void keyReleased(KeyEvent e) {
            super.keyReleased(e);
            switch (e.getKeyCode()) {
                case KeyEvent.VK_LEFT : bL = false; break;
                case KeyEvent.VK_RIGHT : bR = false; break;
                case KeyEvent.VK_UP : bU = false; break;
                case KeyEvent.VK_DOWN : bD = false; break;
                case KeyEvent.VK_SPACE: myTank.fire(); break;
                default: break;
            }
            setDir();
        }

        private void setDir() {
            //当没有任何方向键按下的时候，那么让坦克停止
            if( !bL && !bR && !bU && !bD ) {
                myTank.setMove(false);
            } else {
                myTank.setMove(true);
            }

            //为什么不用if-else 因为有可能是一起按两个方向键，那最后拿到哪个算哪个
            if(bL) myTank.setDir(DirEnum.LEFT);
            if(bR) myTank.setDir(DirEnum.RIGHT);
            if(bU) myTank.setDir(DirEnum.UP);
            if(bD) myTank.setDir(DirEnum.DOWN);
        }
    }

}