J2ME源码,低级界面输入数字

import javax.microedition.midlet.*; import javax.microedition.lcdui.*; public class TestCanvas extends Canvas { private StringBuffer sb=new StringBuffer(); // 定义一个StringBuffer用来保存输入的数字 private int len=4; // 想输入的数字的长度 //private int temp; // 取数字 private static final int WHITE=0x00ffffff; private static final int BLACK=0x00000000; boolean firsttime=true; public TestCanvas() { } protected void paint(Graphics g) { g.setColor(WHITE); g.fillRect(0,0,getWidth(),getHeight()); g.setColor(BLACK); g.drawString(sb.toString(),getWidth()/2,getHeight()/2,Graphics.TOP|Graphics.HCENTER); // 显示输入内容 } protected void keyPressed(int keynum) { /*if (sb.length()==len) // 开始键功能描述 { switch (keynum) { case KEY_STAR: temp=Integer.parseInt(sb.toString()); // 得到了屏幕中输入的数字 // 接下来自己可以利用数字按下*开始动能 break; default: break; } }*/ if(firsttime) { if(sb.length()==0 || sb.length()>0) { switch (keynum) { case KEY_NUM1: sb.append("1"); break; case KEY_NUM2: sb.append("2"); break; case KEY_NUM3: sb.append("3"); break; case KEY_NUM4: sb.append("4"); break; case KEY_NUM5: sb.append("5"); break; case KEY_NUM6: sb.append("6"); break; case KEY_NUM7: sb.append("7"); break; case KEY_NUM8: sb.append("8"); break; case KEY_NUM9: sb.append("9"); break; case KEY_NUM0: sb.append("0"); break; default: break; } } firsttime=false; } else { if(sb.length()>0) { switch (keynum) { case KEY_NUM1: sb.append("1"); break; case KEY_NUM2: sb.append("2"); break; case KEY_NUM3: sb.append("3"); break; case KEY_NUM4: sb.append("4"); break; case KEY_NUM5: sb.append("5"); break; case KEY_NUM6: sb.append("6"); break; case KEY_NUM7: sb.append("7"); break; case KEY_NUM8: sb.append("8"); break; case KEY_NUM9: sb.append("9"); break; case KEY_NUM0: sb.append("0"); break; default: break; } } firsttime=true; } if(sb.length()>0) { if(keynum==KEY_POUND) { sb.deleteCharAt(sb.length()-1); } } repaint(); } protected void keyReapeated(int keynum) { if(sb.length()>0) // 长按一次性去除建函数描述 { if(keynum==KEY_POUND) { sb=null; } } repaint(); } }