man_canvas.java

本光盘是《J2ME无线移动游戏开发》一书的配套光盘

package ch08;

import java.io.IOException;
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;

public class Man_Canvas
    extends GameCanvas
    implements Runnable, CommandListener {

  //代表程序是否运行的状态
  boolean running;

  //存储构成动画的各图像帧
  Image img;

  //代表动画的精灵对象
  Sprite sp;

  //屏幕宽度
  int win_width = getWidth();

  //屏幕高度
  int win_height = getHeight();

  //每帧图像的宽度
  int img_width = 114;

  //每帧图像的高度
  int img_height = 80;

  //绘制上下文
  Graphics g = getGraphics();

  //主MIDlet类实例
  Man_MIDlet mm;

  /*
   3.构造器
   */
  public Man_Canvas(Man_MIDlet mm) {
    super(true);
    this.mm = mm;
    Command exitCommand = new Command("退出", Command.EXIT, 0);
    addCommand(exitCommand);
    setCommandListener(this);

    try {
      img = Image.createImage("/icons/background/man.png");
    }
    catch (IOException e) {
      System.out.println(e.getMessage());
    }
    sp = new Sprite(img, img_width, img_height);

    int x = (win_width - img_width) / 2;
    int y = (win_height - img_height) / 2;
    sp.setPosition(x, y);

    sp.setFrame(0);
    render(g);
    start();
  }

  /*
   4.启动线程
   */
  public void start() {
    running = true;
    Thread t = new Thread(this);
    t.start();
  }

  /*
   5.控制进程
   */
  public void run() {
    while (running) {
      GameKeyInput();
    }
  }

  /*
   6.响应按键
   */
  private void GameKeyInput() {
    int KeyState = getKeyStates();

    if ( (KeyState & UP_PRESSED) != 0) {
      sp.setFrame(0);
      render(g);
    }
    if ( (KeyState & DOWN_PRESSED) != 0) {
      sp.setFrame(3);
      render(g);
    }
    if ( (KeyState & LEFT_PRESSED) != 0) {
      sp.setFrame(1);
      render(g);
    }
    if ( (KeyState & RIGHT_PRESSED) != 0) {
      sp.setFrame(2);
      render(g);
    }
  }

  /*
   7.实现绘制
   */
  private void render(Graphics g) {
    g.setColor(0x000000);
    g.fillRect(0, 0, win_width, win_height);

    sp.paint(g);

    flushGraphics();
  }

  /*
   8.结束线程
   */
  public void stop() {
    running = false;
  }

  /*
   9.响应按钮事件
   */
  public void commandAction(Command c, Displayable s) {
    if (c.getCommandType() == Command.EXIT) {
      mm.quitApp();
    }
  }

}