import java.awt.*;
import java.awt.event.*;

public class TankClient extends Frame {
    public static final int GAME_WIDTH = 800;
    public static final int GAME_HEIGHT = 600;

    Tank myTank = new Tank(50, 50);

    //这是一张虚拟图片
    Image offScreenImage = null;

    //绘制坦克
    public void paint(Graphics g) {
        myTank.draw(g);
    }

    public void update(Graphics g) {
        if(offScreenImage == null) {
            offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT);
        }
        //拿到这个图片的画笔
        Graphics gOffScreen = offScreenImage.getGraphics();
        Color c = gOffScreen.getColor();
        gOffScreen.setColor(Color.GREEN);
        gOffScreen.fillRect(0, 0, GAME_WIDTH, GAME_HEIGHT);
        gOffScreen.setColor(c);
        print(gOffScreen);
        g.drawImage(offScreenImage, 0, 0, null);
    }

    //绘制窗口
    public void launchFrame() {
        this.setLocation(300, 50);
        this.setSize(GAME_WIDTH, GAME_HEIGHT);
        this.setTitle("TankWar");
        addWindowListener(new WindowAdapter() {//关闭窗口
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        setResizable(false);
        this.setBackground(Color.GREEN);

        this.addKeyListener(new KeyMonitor());

        setVisible(true);

        new Thread(new PaintThread()).start();
    }

    public static void main(String[] args) {
        TankClient tc = new TankClient();
        tc.launchFrame();
    }

    private class PaintThread implements Runnable {
        public void run() {
            while(true) {
                repaint();
                try {
                    Thread.sleep(50);
                } catch(InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    //添加键盘监听器
    private class KeyMonitor extends KeyAdapter {
        public void keyPressed(KeyEvent e) {
            myTank.keyPressed(e);
        }
    }

}