基于宝蓝JBUILDER所提供的MIDP编程框架使开发J2ME应用变成一件所见即所得的简单事情：（本文所实现的MIDP应用直接使用了浮点数运算，必须于支持CLDC 1.1的环境下运行。对于使用CLDC 1.0实现浮点数运算的类库，请与作者公司联系【北京讯岚 TEL:010-51833115】，象征性有偿索取）
package jmobile;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class MIDletMain extends MIDlet {
static MIDletMain instance;
Displayable1 displayable = new Displayable1();
Alert alert1;
public MIDletMain() {
instance = this;
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
public void startApp() {
Display.getDisplay(this).setCurrent(this.alert1,displayable);
}
public void pauseApp() {
}
public void destroyApp(boolean unconditional) {
}
public static void quitApp() {
instance.destroyApp(true);
instance.notifyDestroyed();
instance = null;
}
private void jbInit() throws Exception {
alert1 = new Alert("");
alert1.setType(AlertType.INFO);
alert1.setTimeout(2000);
alert1.setString("北京讯岚 2004");
alert1.setTitle("");
alert1.setImage(Image.createImage("/jmobile/Untitled-1.png"));
}
}
public class Displayable1 extends Form implements CommandListener {
ChoiceGroup choiceGroup1;
TextField textField1;
Alert alert1;
public Displayable1() {
super("QuickLine");
try {
jbInit();
}
catch (Exception e) {
e.printStackTrace();
}
}
private void jbInit() throws Exception {
// Set up this Displayable to listen to command events
String[] str = {
"北京", "上海", "深圳", "除北京、上海和深圳的其他地方"};
choiceGroup1 = new ChoiceGroup("", ChoiceGroup.EXCLUSIVE, str, null);
textField1 = new TextField("", "", 15, TextField.ANY);
alert1 = new Alert("");
alert1.setType(AlertType.INFO);
textField1.setLabel("您欲计算的收入");
textField1.setConstraints(TextField.DECIMAL);
choiceGroup1.setLabel("选择您所在的城市");
choiceGroup1.setFitPolicy(Choice.TEXT_WRAP_OFF);
choiceGroup1.setPreferredSize(145, 20);
this.setCommandListener(new Displayable1_this_commandAdapter(this));
setCommandListener(this);
// add the Exit command
addCommand(new Command("计算", Command.OK, 1));
addCommand(new Command("Exit", Command.EXIT, 2));
this.append(textField1);
this.append(choiceGroup1);
}
public void commandAction(Command command, Displayable displayable) {
/** @todo Add command handling code */
if(command.getCommandType()==Command.OK){
try{
String str=col(this.textField1.getString());
this.textField1.setString("");
this.alert1.setTimeout(Alert.FOREVER);
this.alert1.setString("您应缴纳个人所得税 "+str+" 元");
Display.getDisplay(MIDletMain.instance).setCurrent(this.alert1,this);
}
catch(Exception e)
{
this.textField1.setString("");
}
}
if ((command.getCommandType() == Command.EXIT) || (command.getCommandType() == Command.STOP)) {
// stop the MIDlet
MIDletMain.quitApp();
}
}
void this_commandAction(Command command, Displayable displayable) {
}
private String col(String input) {
try{
float v1=800;
switch(this.choiceGroup1.getSelectedIndex())
{
case 0:
v1=1000;
break;
case 1:
v1=1000;
break;
case 2:
v1=1600;
break;
}
float v2 = java.lang.Float.valueOf(input).floatValue();
if (java.lang.Float.isNaN(v2)) {
return "ERROR";
}
float v3 = v2 - v1;
if (v3 <= 0) {
v3 = 0;
return java.lang.Float.toString(v3);
}
if (v3 <= 500) {
return java.lang.Float.toString(v3 * 0.05f);
}
if (v3 <= 2000) {
return java.lang.Float.toString(v3 * 0.1f - 25);
}
if (v3 <= 5000) {
return java.lang.Float.toString(v3 * 0.15f - 125);
}
if (v3 <= 20000) {
return java.lang.Float.toString(v3 * 0.2f - 375);
}
if (v3 <= 40000) {
return java.lang.Float.toString(v3 * 0.25f - 1375);
}
if (v3 <= 60000) {
return java.lang.Float.toString(v3 * 0.3f - 3375);
}
if (v3 <= 80000) {
return java.lang.Float.toString(v3 * 0.35f - 6375);
}
if (v3 <= 100000) {
return java.lang.Float.toString(v3 * 0.4f - 10375);
}
return java.lang.Float.toString(v3 * 0.45f - 15375);
}
catch(Exception e){
return "ERROR";
}
}
class Displayable1_this_commandAdapter
implements javax.microedition.lcdui.CommandListener {
Displayable1 adaptee;
Displayable1_this_commandAdapter(Displayable1 adaptee) {
this.adaptee = adaptee;
}
public void commandAction(Command command, Displayable displayable) {
adaptee.this_commandAction(command, displayable);
}
}
}
