[JAVA100 example]013, composite dropdown list

Source: Internet
Author: User

Import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.border.*;

import java.util.*;

import Java.text.SimpleDateFormat;


* <p>title:combobox dropdown field Demo </p>

* <p>description: Format today's date </p>
by selecting or entering a date format

* <p>copyright:copyright (c) 2003</p>

* <p>Filename:ComboBoxDemo.java</p>

* @version 1.0


public class Comboboxdemo extends JPanel

implements ActionListener {

static JFrame frame;

JLabel result;

String Currentpattern;


*<br> Method Description: constructor. Initializing the form widget

*<br> input Parameters:

*<br> return type:


public Comboboxdemo () {

SetLayout (This, Boxlayout.page_axis) (new boxlayout);

string[] Patternexamples = {

"dd mmmmm yyyy",

"DD. Mm.yy ",


"yyyy. Mm.dd g´at´hh:mm:ss z ",

"EEE, MMM d,´´yy",

"h:mm a",


"k:mm a,z",

"yyyy. MMMMM.DD GGG hh:mm AAA "


currentpattern = patternexamples[0];

//Set up a specification user interface

JLabel patternLabel1 = new JLabel ("Enter a character format or");

JLabel PatternLabel2 = new JLabel ("Select one from the Drop-down list:");

JComboBox patternlist = new JComboBox (patternexamples);

patternlist.seteditable (TRUE),//Callout here ComboBox editable

Patternlist.addactionlistener (this);

//Create a display result user interface

JLabel ResultLabel = new JLabel ("Current date/Time",

jlabel.leading);//equivalent to left

result = new JLabel ("");

Result.setforeground (Color.Black);

Result.setborder (Borderfactory.createcompoundborder (

Borderfactory.createlineborder (color.black),

Borderfactory.createemptyborder (5,5,5,5)


//Layout Components

JPanel Patternpanel = new JPanel ();

patternpanel.setlayout (New BoxLayout (Patternpanel,


Patternpanel.add (PATTERNLABEL1);

Patternpanel.add (PATTERNLABEL2);

Patternlist.setalignmentx (component.left_alignment);

Patternpanel.add (patternlist);

JPanel Resultpanel = new JPanel (new GridLayout (0, 1));

Resultpanel.add (ResultLabel);

Resultpanel.add (Result);

Patternpanel.setalignmentx (component.left_alignment);

Resultpanel.setalignmentx (component.left_alignment);

Add (Patternpanel);

Add (Box.createrigidarea (new Dimension (0, 10));

Add (Resultpanel);

SetBorder (Borderfactory.createemptyborder (10,10,10,10));

reformat ();



*<br> Method Description: Event handling

*<br> input Parameters:

*<br> return type:


public void actionperformed (ActionEvent e) {

JComboBox cb = (JComboBox) e.getsource ();

String newselection = (string) cb.getselecteditem ();

Currentpattern = newselection;

reformat ();



*<br> Method Description: Format and display today's date

*<br> input Parameters:

*<br> return type:


public void reformat () {

Date today = new Date ();

SimpleDateFormat formatter =

new SimpleDateFormat (Currentpattern);

try {

String datestring = Formatter.format (today);

Result.setforeground (Color.Black);

Result.settext (datestring);

} catch (IllegalArgumentException iae) {

Result.setforeground (color.red);

Result.settext ("Error:" + iae.getmessage ());




*<br> Method Description: Main method

*<br> input Parameters:

*<br> return type:


public static void Main (string[] args) {

jframe.setdefaultlookandfeeldecorated (TRUE);

Create a form

frame = new JFrame ("Comboboxdemo");

frame.setdefaultcloseoperation (jframe.exit_on_close);

//Create a face plate container

jcomponent Newcontentpane = new Comboboxdemo ();

Newcontentpane.setopaque (TRUE);

Frame.setcontentpane (Newcontentpane);

//Display form

Frame.pack ();

frame.setvisible (TRUE);



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