坦克大战0.41-0.7

版本0.41
功能：
使用双缓冲消除闪烁现象
原因：
刷新重画频率太快，paint方法还没有完成
逐条显示
解决办法：
将所有东西画在虚拟图片上，一次性显示出来
注意：
如果不能理解透彻就照抄本版本代码，不影响对J2SE的练习功效

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

public class TankClient extends Frame{
	

	int x=50, y=50;
	
	Image offScreenImage = null;
	
	public void paint(Graphics g) {
		Color c = g.getColor();
		g.setColor(Color.red);
		g.fillOval(x, y, 30, 30);
		g.setColor(c);
		
		y += 5;
	}
	
	public void update(Graphics g) {
		if(offScreenImage == null){
			offScreenImage = this.createImage(800, 600);
		}
		
		Graphics gOffScreen = offScreenImage.getGraphics();
		Color c=gOffScreen.getColor();
		gOffScreen.setColor(Color.GREEN);
		gOffScreen.fillRect(0, 0, 800, 600);
		gOffScreen.setColor(c);
		paint(gOffScreen);
		g.drawImage(offScreenImage, 0, 0, null);
	}

	public void lanchFrame(){
		this.setLocation(200, 100);
		this.setSize(800, 600);
		this.setTitle("TankWar");
		this.addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
		setVisible(true);
		this.setBackground(Color.GREEN);
		this.setResizable(false);
		
		new Thread(new paintThread()).start();
	}
	
	public static void main(String[] args) {
		TankClient tc = new TankClient();
		tc.lanchFrame();

	}
	
	
	private class paintThread implements Runnable{
		public void run() {
			while(true){
				repaint();
				try {
					Thread.sleep(20);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}
	}

}

版本0.5
功能：
代码重构
   将以后可能需要多处改变的量定义为常量
Frame的宽度和高度
    常量名一般大写
注意：
常量一般是public static final的

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;
	int x=50, y=50;
	
	Image offScreenImage = null;
	
	public void paint(Graphics g) {
		Color c = g.getColor();
		g.setColor(Color.red);
		g.fillOval(x, y, 30, 30);
		g.setColor(c);
		
		y += 5;
	}
	
	public void update(Graphics g) {
		if(offScreenImage == null){
			offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT);
		}
		
		Graphics gOffScreen = offScreenImage.getGraphics();
		Color c=gOffScreen.getColor();
		gOffScreen.setColor(Color.GREEN);
		gOffScreen.fillRect(0, 0, GAME_WIDTH, GAME_HEIGHT);
		gOffScreen.setColor(c);
		paint(gOffScreen);
		g.drawImage(offScreenImage, 0, 0, null);
	}

	public void lanchFrame(){
		this.setLocation(200, 100);
		this.setSize(GAME_WIDTH, GAME_HEIGHT);
		this.setTitle("TankWar");
		this.addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
		setVisible(true);
		this.setBackground(Color.GREEN);
		this.setResizable(false);
		
		new Thread(new paintThread()).start();
	}
	
	public static void main(String[] args) {
		TankClient tc = new TankClient();
		tc.lanchFrame();

	}
	
	
	private class paintThread implements Runnable{
		public void run() {
			while(true){
				repaint();
				try {
					Thread.sleep(20);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}
	}

}

版本0.6
功能：
让坦克听从我们的指挥
添加键盘监听器类KeyMonitor
TankClient添加键盘监听器
针对不同的键改变坦克的位置，与重画
线程结合产生不同方向运动
注意：
switch case语句中break语句的运用
写程序要 循序渐进！

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;
	int x=50, y=50;
	
	Image offScreenImage = null;
	
	public void paint(Graphics g) {
		Color c = g.getColor();
		g.setColor(Color.red);
		g.fillOval(x, y, 30, 30);
		g.setColor(c);
		
	}
	
	public void update(Graphics g) {
		if(offScreenImage == null){
			offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT);
		}
		
		Graphics gOffScreen = offScreenImage.getGraphics();
		Color c=gOffScreen.getColor();
		gOffScreen.setColor(Color.GREEN);
		gOffScreen.fillRect(0, 0, GAME_WIDTH, GAME_HEIGHT);
		gOffScreen.setColor(c);
		paint(gOffScreen);
		g.drawImage(offScreenImage, 0, 0, null);
	}

	public void lanchFrame(){
		this.setLocation(200, 100);
		this.setSize(GAME_WIDTH, GAME_HEIGHT);
		this.setTitle("TankWar");
		this.addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
		
		this.addKeyListener(new KeyMonitor());
		
		setVisible(true);
		this.setBackground(Color.GREEN);
		this.setResizable(false);
		
		new Thread(new paintThread()).start();
	}
	
	public static void main(String[] args) {
		TankClient tc = new TankClient();
		tc.lanchFrame();

	}
	
	
	private class paintThread implements Runnable{
		public void run() {
			while(true){
				repaint();
				try {
					Thread.sleep(20);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}
	}
	
	private class KeyMonitor extends KeyAdapter{

		public void keyPressed(KeyEvent e) {
			int key = e.getKeyCode();
			switch(key){
				case KeyEvent.VK_LEFT:
					x -= 5; break;
				case KeyEvent.VK_UP:
					y -= 5; break;
				case KeyEvent.VK_RIGHT:
					x += 5; break;
				case KeyEvent.VK_DOWN:
					y += 5; break;
			}
		}
		
	}
}

版本0.7--重要版本
功能：
将坦克单独包装成类
步骤：
建立Tank类
为Tank类添加成员变量
添加draw方法，使Tank类独立控制自己的画法
添加Tank类处理按键的方法
根据Tank类修改TankClient类
掌握：
面向对象的思考方法
细节隐藏、构建单独的类、首先考虑系统中有哪些类

合适的方法应该出现在合适的类中

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);
	
	Image offScreenImage = null;
	
	public void paint(Graphics g) {
		myTank.draw(g);
	}
	
	public void update(Graphics g) {
		if(offScreenImage == null){
			offScreenImage = this.createImage(GAME_WIDTH, GAME_HEIGHT);
		}
		
		Graphics gOffScreen = offScreenImage.getGraphics();
		Color c=gOffScreen.getColor();
		gOffScreen.setColor(Color.GREEN);
		gOffScreen.fillRect(0, 0, GAME_WIDTH, GAME_HEIGHT);
		gOffScreen.setColor(c);
		paint(gOffScreen);
		g.drawImage(offScreenImage, 0, 0, null);
	}

	public void lanchFrame(){
		this.setLocation(200, 100);
		this.setSize(GAME_WIDTH, GAME_HEIGHT);
		this.setTitle("TankWar");
		this.addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
		
		this.addKeyListener(new KeyMonitor());
		
		setVisible(true);
		this.setBackground(Color.GREEN);
		this.setResizable(false);
		
		new Thread(new paintThread()).start();
	}
	
	public static void main(String[] args) {
		TankClient tc = new TankClient();
		tc.lanchFrame();

	}
	
	
	private class paintThread implements Runnable{
		public void run() {
			while(true){
				repaint();
				try {
					Thread.sleep(20);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		}
	}
	
	private class KeyMonitor extends KeyAdapter{

		public void keyPressed(KeyEvent e) {
			myTank.keyPressed(e);
		}
	}
}

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


public class Tank {
	int x, y;
	
	public Tank(int x, int y) {
		this.x = x;
		this.y = y;
	}

	public void draw(Graphics g){
		Color c = g.getColor();
		g.setColor(Color.red);
		g.fillOval(x, y, 30, 30);
		g.setColor(c);
	}
	
	public void keyPressed(KeyEvent e){
		int key = e.getKeyCode();
		switch(key){
			case KeyEvent.VK_LEFT:
				x -= 5; break;
			case KeyEvent.VK_UP:
				y -= 5; break;
			case KeyEvent.VK_RIGHT:
				x += 5; break;
			case KeyEvent.VK_DOWN:
				y += 5; break;
		}
	}
}