canvasnotifydemo.java

Java ME手机应用开发大全一书的配套光盘上的源码

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class CanvasnotifyDemo extends MIDlet {	
    private Display display;
    public CanvasnotifyDemo() {
		//获取MIDlet的Display对象实例
        display=Display.getDisplay(this);
    }
    public void startApp() throws MIDletStateChangeException {
        display.setCurrent(new notifyDemoCanvas());
    }
    public void pauseApp() {
    }
    public void destroyApp(boolean unconditional) {
    }
    class notifyDemoCanvas extends Canvas {
        int width, height;
        int deltaX, deltaY;
        int x,y;
        
        public notifyDemoCanvas() { 
			//获得屏幕的尺寸
            width = getWidth();
            height = getHeight();
        }
        public void paint(Graphics g) { 
			//调用paint()方法是显示的提示信息
            System.out.println("绘制屏幕");
            System.out.println("显示是否可见?"+isShown());
			//填充整个屏幕
            g.setColor(0xFFFFFF);
            g.fillRect(0,0,width,height);
         }
        protected void showNotify(){
			//显示屏幕时显示的提示信息
        	System.out.println("showNotify方法调用");
        	System.out.println("显示是否可见?"+isShown());
        }
        protected void hideNotify(){
			//隐藏屏幕时显示的提示信息
        	System.out.println("hideNotify方法调用");
        	System.out.println("显示是否可见n?"+isShown());
        }
    }
}