Java/J2ME/Form
Содержание
Change Label Text
/*--------------------------------------------------
* ChangeLabelText.java
*
* Example from the book: Core J2ME Technology
* Copyright John W. Muchow http://www.CoreJ2ME.ru
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class ChangeLabelText extends MIDlet implements CommandListener
{
private Display display; // Reference to Display object
private Form fmMain; // The main form
private StringItem siUser; // The message
private Command cmNext; // Next label and message
private Command cmExit; // Command to exit the MIDlet
public ChangeLabelText()
{
display = Display.getDisplay(this);
// Create text message and commands
siUser = new StringItem("UserId: ", "johnm");
cmNext = new Command("Next", Command.SCREEN, 1);
cmExit = new Command("Exit", Command.EXIT, 1);
// Create Form, add Command & StringItem, listen for events
fmMain = new Form("Preferences");
fmMain.addCommand(cmExit);
fmMain.addCommand(cmNext);
fmMain.append(siUser);
fmMain.setCommandListener(this);
}
// Called by application manager to start the MIDlet.
public void startApp()
{
display.setCurrent(fmMain);
}
public void pauseApp()
{ }
public void destroyApp(boolean unconditional)
{ }
public void commandAction(Command c, Displayable s)
{
if (c == cmNext)
{
// This method is inherited from the Item class
siUser.setLabel("Account #: ");
// Change the text
siUser.setText("731");
// Remove the Next command
fmMain.removeCommand(cmNext);
}
else if (c == cmExit)
{
destroyApp(false);
notifyDestroyed();
}
}
}
Create Form With Items
//jad file (please verify the jar size)
/*
MIDlet-Name: CreatingFormWithItems
MIDlet-Version: 1.0
MIDlet-Vendor: MyCompany
MIDlet-Jar-URL: CreatingFormWithItems.jar
MIDlet-1: CreatingFormWithItems, , CreatingFormWithItems
MicroEdition-Configuration: CLDC-1.0
MicroEdition-Profile: MIDP-1.0
MIDlet-JAR-SIZE: 100
*/
import javax.microedition.lcdui.rumand;
import javax.microedition.lcdui.rumandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.StringItem;
import javax.microedition.midlet.MIDlet;
public class CreatingFormWithItems extends MIDlet implements CommandListener {
private Display display;
private Form form;
private Command exit = new Command("Exit", Command.SCREEN, 1);
public CreatingFormWithItems() {
display = Display.getDisplay(this);
StringItem messages[] = new StringItem[] { new StringItem("Welcome, ", "glad you could come."),
new StringItem("Hello, ", "Mary.") };
form = new Form("Display Form with Items", messages);
form.addCommand(exit);
form.setCommandListener(this);
}
public void startApp() {
display.setCurrent(form);
}
public void pauseApp() {
}
public void destroyApp(boolean unconditional) {
}
public void commandAction(Command command, Displayable displayable) {
if (command == exit) {
destroyApp(true);
notifyDestroyed();
}
}
}
Display Stats
/*--------------------------------------------------
* DisplayStats.java
*
* Example from the book: Core J2ME Technology
* Copyright John W. Muchow http://www.CoreJ2ME.ru
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class DisplayStats extends MIDlet implements CommandListener
{
private Display display; // Reference to Display object
private Form fmMain; // A Form
private Alert alTest; // An Alert
private Command cmExit; // A Command to exit the MIDlet
public DisplayStats()
{
display = Display.getDisplay(this);
cmExit = new Command("Exit", Command.SCREEN, 1);
fmMain = new Form("Welcome");
fmMain.addCommand(cmExit);
fmMain.setCommandListener(this);
System.out.println("Display " + (display.isColor() ? "does" : "does not") + " support Color");
System.out.println("Number of colors: " + display.numColors());
}
// Called by application manager to start the MIDlet.
public void startApp()
{
alTest = new Alert("Alert", "This alert screen will be followed by the main form", null, null);
alTest.setTimeout(Alert.FOREVER);
display.setCurrent(alTest, fmMain);
}
// We are about to be placed in the Paused state
public void pauseApp()
{
}
// We are about to enter the Destroyed state
public void destroyApp(boolean unconditional)
{
}
// Check to see if the Exit command was selected
public void commandAction(Command c, Displayable s)
{
if (c == cmExit)
{
destroyApp(true);
notifyDestroyed();
}
}
}
Form Example MIDlet
/*
J2ME in a Nutshell
By Kim Topley
ISBN: 0-596-00253-X
*/
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.StringItem;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
public class FormExampleMIDlet extends MIDlet {
// The MIDlet"s Display object
protected Display display;
// Flag indicating first call of startApp
protected boolean started;
protected void startApp() {
if (!started) {
display = Display.getDisplay(this);
Form form = new Form("Item Layout");
form.append("Hello");
form.append("World");
form.append("\nLet"s start\na new line\n");
form.append("This is quite a long string that may not fit on one line");
form.append(new TextField("Name", "J. Doe", 32, TextField.ANY));
form.append("Address");
form.append(new TextField(null, null, 32, TextField.ANY));
display.setCurrent(form);
started = true;
}
}
protected void pauseApp() {
}
protected void destroyApp(boolean unconditional) {
}
}
Form Juggle
/*--------------------------------------------------
* FormJuggle.java
*
* Show how a Form component handles inserting and
* setting (replacing) Items
*
* Example from the book: Core J2ME Technology
* Copyright John W. Muchow http://www.CoreJ2ME.ru
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class FormJuggle extends MIDlet implements CommandListener
{
private Display display; // Reference to display object
private Form fmMain; // The main form
private Command cmInsert; // Command to insert items
private DateField dfDate; // Display date
private TextField tfSize; // Product size
private TextField tfQuantity; // Product quantity
private int dateIndex; // Index of dfDate
public FormJuggle()
{
display = Display.getDisplay(this);
// Create the date and populate with current date
dfDate = new DateField("", DateField.DATE);
dfDate.setDate(new java.util.Date());
// Define two textfields and two commands
tfSize = new TextField("Size", "Large", 5, TextField.ANY);
tfQuantity = new TextField("Quantity:", "3", 2, TextField.NUMERIC);
cmInsert = new Command("Insert", Command.SCREEN, 1);
// Create the form, add insert command
fmMain = new Form("Form Stuff");
fmMain.addCommand(cmInsert);
// Append date to form & save index value where it was inserted
dateIndex = fmMain.append(dfDate);
// Capture events
fmMain.setCommandListener(this);
}
// Called by application manager to start the MIDlet.
public void startApp()
{
display.setCurrent(fmMain);
}
public void pauseApp()
{ }
public void destroyApp(boolean unconditional)
{ }
public void commandAction(Command c, Displayable s)
{
if (c == cmInsert)
{
// One item on form, insert textfield prior to datefield
if (fmMain.size() == 1)
{
fmMain.insert(dateIndex, tfQuantity);
dateIndex += 1; // Date index has changed, update it
}
// If two items and last item is datefield, replace it
else if (fmMain.size() == 2 && fmMain.get(1) == dfDate)
fmMain.set(dateIndex, tfSize);
}
}
}
Form Scroll
/*--------------------------------------------------
* FormScroll.java
*
* Show how a Form component handles scrolling
* when multiple Items are on the display
*
* Copyright John W. Muchow http://www.CoreJ2ME.ru
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class FormScroll extends MIDlet implements CommandListener
{
private Display display; // Reference to display object
private Form frmMain; // The main form
private Command cmdExit; // Command to exit
private TextField txfSize; // Product size
private ChoiceGroup chgEmail; // Choice group
private Gauge gauVolume; // Volume
public FormScroll()
{
display = Display.getDisplay(this);
// Create TextField
txfSize = new TextField("Size", "Large", 5, TextField.ANY);
// Create an exclusive (radio) choice group, and append entries
chgEmail = new ChoiceGroup("Email Options", Choice.EXCLUSIVE);
chgEmail.append("Read", null);
chgEmail.append("Forward", null);
chgEmail.append("Delete", null);
// Create the gauge
gauVolume = new Gauge("Sound Level", true, 30, 4);
cmdExit = new Command("Exit", Command.EXIT, 1);
// Create the form
frmMain = new Form("Form Stuff");
frmMain.append(txfSize);
frmMain.append(chgEmail);
frmMain.append(gauVolume);
frmMain.addCommand(cmdExit);
// Capture events
frmMain.setCommandListener(this);
}
// Called by application manager to start the MIDlet.
public void startApp()
{
display.setCurrent(frmMain);
}
public void pauseApp()
{ }
public void destroyApp(boolean unconditional)
{ }
public void commandAction(Command c, Displayable s)
{
if (c == cmdExit)
{
destroyApp(false);
notifyDestroyed();
}
}
}
Read Display File
/*--------------------------------------------------
* ReadDisplayFile.java
*
* Example from the book: Core J2ME Technology
* Copyright John W. Muchow http://www.CoreJ2ME.ru
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.io.*;
public class ReadDisplayFile extends MIDlet implements CommandListener
{
private Display display; // Reference to Display object
private Form fmMain; // Main form
private Command cmHelp; // Command to show a help file
private Command cmExit; // Command to exit the MIDlet
private Alert alHelp; // Alert to display help file text
public ReadDisplayFile()
{
display = Display.getDisplay(this);
cmHelp = new Command("Help", Command.SCREEN, 1);
cmExit = new Command("Exit", Command.EXIT, 1);
fmMain = new Form("Read File");
fmMain.addCommand(cmExit);
fmMain.addCommand(cmHelp);
fmMain.setCommandListener(this);
}
public void startApp()
{
display.setCurrent(fmMain);
}
public void pauseApp()
{ }
public void destroyApp(boolean unconditional)
{ }
public void commandAction(Command c, Displayable s)
{
if (c == cmHelp)
{
String str;
// Access the resource and read its contents
if ((str = readHelpText()) != null)
{
// Create an Alert to display the help text
alHelp = new Alert("Help", str, null, null);
alHelp.setTimeout(Alert.FOREVER);
display.setCurrent(alHelp, fmMain);
}
}
else if (c == cmExit)
{
destroyApp(false);
notifyDestroyed();
}
}
private String readHelpText()
{
InputStream is = getClass().getResourceAsStream("help.txt");
try
{
StringBuffer sb = new StringBuffer();
int chr, i = 0;
// Read until the end of the stream
while ((chr = is.read()) != -1)
sb.append((char) chr);
return sb.toString();
}
catch (Exception e)
{
System.out.println("Unable to create stream");
}
return null;
}
}
Verify Area Code
/*--------------------------------------------------
* VerifyAreaCode.java
*
* Example from the book: Core J2ME Technology
* Copyright John W. Muchow http://www.CoreJ2ME.ru
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class VerifyAreaCode extends MIDlet implements CommandListener
{
private Display display; // Reference to Display object
private Form fmMain; // The main form
private Command cmTest; // Next label and message
private Command cmExit; // Command to exit the MIDlet
private TextField tfPhone; // Phone number
private String areaCodeTable [][] = {
{"512", "912"}, // Old area code, new area code
{"717", "917"} };
public VerifyAreaCode()
{
display = Display.getDisplay(this);
// Create commands
cmTest = new Command("Test", Command.SCREEN, 1);
cmExit = new Command("Exit", Command.EXIT, 1);
// Textfield for phone number
tfPhone = new TextField("Phone:", "", 10, TextField.PHONENUMBER);
// Create Form, add Commands & textfield, listen for events
fmMain = new Form("Area Codes");
fmMain.addCommand(cmExit);
fmMain.addCommand(cmTest);
fmMain.append(tfPhone);
fmMain.setCommandListener(this);
}
// Called by application manager to start the MIDlet.
public void startApp()
{
display.setCurrent(fmMain);
}
public void pauseApp()
{ }
public void destroyApp(boolean unconditional)
{ }
public void commandAction(Command c, Displayable s)
{
if (c == cmTest)
{
if (tfPhone.size() == 10)
{
char buffer[] = new char[10];
// Get phone number into byte array
tfPhone.getChars(buffer);
// Call method to check the area code table.
// Create a new StringItem to display,
// passing in "null" as the StringItem
StringItem tmp = new StringItem(null, ("The area code " + (areaCodeLookup(buffer) ? "has" : "has not") + " been updated."));
// Place at the end of the form
if (fmMain.size() == 1) // Only tfPhone on form
fmMain.append(tmp);
else // Replace previous StringItem
fmMain.set(1, tmp);
}
}
else if (c == cmExit)
{
destroyApp(false);
notifyDestroyed();
}
}
/*--------------------------------------------------
* Compare the area code the user entered with the
* area code table. If a match is found, replace
* the user"s code with the new code from the table
*-------------------------------------------------*/
private boolean areaCodeLookup(char [] buffer)
{
// Get the area code (only) from the users entry
String str = new String(buffer, 0, 3);
for (int x = 0; x < areaCodeTable.length; x++)
{
// If we find a match in the table
if (str.equals(areaCodeTable[x][0]))
{
// Delete the area code
tfPhone.delete(0, 3);
// Insert the new area code
tfPhone.insert(areaCodeTable[x][1].toCharArray(), 0, 3, 0);
return true;
}
}
return false;
}
}
