j2me中canvas的基础用法
上一篇 / 下一篇 2010-04-22 17:52:44 / 个人分类：开发积累
最近学习了一些j2me的开发，在学到画布（canvas)里遇到了一些问题，没了思路，不知道如何去写代码，现在贴出来做一个总结也希望可以帮到初学者；
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.lcdui.*;
public class test extends MIDlet {
private Display dis;
private MyCanvas canvas;
public test(){
dis=Display.getDisplay(this);
canvas=new MyCanvas(this);
}
protected void startApp() throws MIDletStateChangeException {
dis.setCurrent(canvas);//显示对象为canvas
}
protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
}
protected void exit(){
notifyDestroyed();//退出程序
}
protected void pauseApp() {
}
class MyCanvas extends Canvas implements CommandListener{
private Command cmdEXIT=new Command("EXIT",Command.EXIT,1);//定义一个退出按钮
private String direction;
private test test;
private Image image=null;//定义一个图片，初始化值为null
public MyCanvas(test test){
direction="2=up 8=dn 4=left 6=right";
this.test=test;
addCommand(cmdEXIT);
setCommandListener(this);//给退出按钮加一个事件
}
public void paint(Graphics g){
g.setColor(150,150,100);//RGB颜色值
g.drawRect(0, 0,20, 20);
g.fillRect(0,0,20,20);
g.drawString("this is the Second line",25,0,g.TOP|g.LEFT);//以上为第一行
g.setColor(200,200,10);//RGB颜色值
g.drawRect(0,20,20,20);
g.fillRect(0,20,20,20);
g.drawString("this is the Second line", 25,20, g.TOP|g.LEFT);//这是第二行
g.setColor(210,200,190);//RGB颜色值
g.drawRect(0,40,20,20);
g.fillRect(0,40,20,20);
g.drawString("this is the third line",25,40,g.TOP|g.LEFT);//这是第三行
try{
image=Image.createImage("/dd.png");//实例化图片
g.drawImage(image, 0, 60,20);
g.drawString("this is the fourth line",35,60,g.LEFT|g.TOP);
}
catch(Exception e){
System.out.println("报错了，请查看原因");
}
}
public void commandAction(Command c,Displayable d){
if(c==cmdEXIT){
test.exit();
}
}
}
}
最后出来的结果如下：
希望高手也可以给予指正，本人初学，水平不高。。
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