gameactiondemo.java

j2me方向的控制的演示,手机上的up,down,left,right等的控制的和显示

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class GameActionDemo extends MIDlet {	
    private Display display;
	
    public GameActionDemo() {
        display=Display.getDisplay(this);
    }
    
    public void startApp() throws MIDletStateChangeException {
        display.setCurrent(new GameActionDemoCanvas());
    }

    /**
     * Pause the MIDlet
     */
    public void pauseApp() {
    }

    /**
     * Called by the framework before the application is unloaded
     */
    public void destroyApp(boolean unconditional) {
    }

    class GameActionDemoCanvas extends Canvas {
        int width, height;
        int deltaX, deltaY;
        int x,y;
        
        public GameActionDemoCanvas() {      
            //draw a 8x10 net
            deltaX=this.getWidth()/8;
            deltaY=this.getHeight()/10;
            width=deltaX*8;
            height=deltaY*10;
            x=0;
            y=0;
        }
        public void paint(Graphics g) {         
            //set background to white
            g.setColor(0xFFFFFF);
            g.fillRect(0,0,width,height);
            
            //set foreground color to black
            g.setColor(0x000000);
            g.fillRect(x,y,deltaX,deltaY);
        }
        
        public void keyPressed(int keycode) {
            switch(getGameAction(keycode)) {
            case Canvas.DOWN:
                y+=deltaY;
                if(y>=height) {
                    y-=height;
                    repaint(x,0,deltaX,height);
                }
                else {
                    repaint(x,y-deltaY,deltaX,2*deltaY);
                }
                break;
            case Canvas.UP:
                y-=deltaY;
                if(y<0) {
                    y+=height;
                    repaint(x,0,deltaX,height);
                }
                else {
                    repaint(x,y,deltaX,2*deltaY);
                }
                break;
            case Canvas.LEFT:
                x-=deltaX;
                if(x<0) {
                    x+=width;
                    repaint(0,y,width,deltaY);
                }
                else {
                    repaint(x,y,deltaX*2,deltaY);
                }
                break;
            case Canvas.RIGHT:
                x+=deltaX;
                if(x>=width) {
                    x-=width;
                    repaint(0,y,width,deltaY);
                }
                else {
                    repaint(x-deltaX,y,deltaX*2,deltaY);
                }
                break;
            default:
            }
        }
    }
}