写了类似这样的结构：
{
- Java code
public class myj2me extends MIDlet { Display display.....//初始化过程略去 //构造函数中 canvas1 can1 = new canvas1(this); canvas2 can1 = new canvas2(this); public void startApp(){display.setCurrent(can1);} public void setcanvas1(){display.setCurrent(can1);} public void setcanvas2(){display.setCurrent(can2);}}class canvas1 extends Canvas implements CommandListener { myj2me j2me; public canvas1(myj2me my_j2me) { j2me = my_j2me; } public void commandAction(Command cmd,Displayable dis){ if(cmd==...){ j2me.setcanvas2(); } }}class canvas2 extends Canvas implements CommandListener { myj2me j2me; public canvas2(myj2me my_j2me) { j2me = my_j2me; } public void commandAction(Command cmd,Displayable dis){ if(cmd==...){ j2me.setcanvas3(); } }}初学j2me，想当然的就这样写了，果然有问题，若先显示can1,从can1通过调用setcanvans2()切换到can2的时候屏幕不会刷新，也就是can1的界面还在。
请教一下要如何才能刷新屏幕呢？
------解决方案--------------------------------------------------------
是你的Canvas2的对象错了：
canvas1 can1 = new canvas1(this);
canvas2 can1 = new canvas2(this); ----------------这一行
修改为：
canvas1 can1 = new canvas1(this);
canvas2 can2 = new canvas2(this);
就可以了