simplegamecanvas.java

J2ME手机游戏开发技术详解随书光盘

// Any use of this code and/or information below is subject to the
// license terms: http://wireless.java.sun.com/berkeley_license.html

import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;

public class SimpleGameCanvas    extends GameCanvas    implements Runnable 
{
  private Graphics g;
  private int[ ] clrs = {0X0000FFFF,0x00FF0000,0x0000FF00,0x000000FF};
  private int curColor = 0X000000FF;
  private int[ ] rgb;
  private int curX = 0,curY = 0;
  private int maxX, maxY;
  private boolean mTrucking;
  private long mFrameDelay;

  
  public SimpleGameCanvas() {
   super(true);
   //初始化用于Alpha 绘图的像素数组
   rgb = new int[81];
   for(int i = 0;i<81;i++)
   rgb[i] = 0x88FFFFFF;
   g = getGraphics( );
   //计算方块移动范围
   maxX = getWidth( ) -9;
   maxY = getHeight( ) -9;
  }
  
  public void start() {
    mTrucking = true;
    Thread t = new Thread(this);
    t.start();
  }
  
  public void stop() { mTrucking = false; }
  
  public void run() {
    Graphics g = getGraphics();
    
    while (mTrucking == true) {
      tick();
      input();
      render(g);
      try { Thread.sleep(mFrameDelay); }
      catch (InterruptedException ie) {}
    }
  }
  
  private void tick() {
    
  }
  
  private void input() {
        int keyState = getKeyStates( );
        //判断ABCD键是否被按下
        if((keyState & GAME_A_PRESSED) != 0)
        curColor=clrs[0];
        else if((keyState & GAME_B_PRESSED) != 0)
	curColor=clrs[1];
	else if((keyState & GAME_C_PRESSED) != 0)
	curColor=clrs[2];
	else if((keyState & GAME_D_PRESSED) != 0)
	curColor=clrs[3];
	//判断上下左右键是否被按下
	if((keyState & UP_PRESSED) != 0 && curY>0)
	curY --;
	if((keyState & DOWN_PRESSED) != 0 && curY<maxY)
	curY ++;
	if((keyState & LEFT_PRESSED) != 0 && curX>0)
	curX --;
	if((keyState & RIGHT_PRESSED) != 0 && curX<maxX)
	curX ++;
        
  }
  
  private void render(Graphics g) {
  	g.setColor(curColor);
	g.fillRect(curX,curY,9,9);
	flushGraphics( );
	//通过Alpha 混合使原来的方块颜色变浅
	g.drawRGB(rgb,0,9,curX,curY,9,9,true);
  }
}