[JAVA100 example]013, composite dropdown list

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 ",


"Mm/dd/yy",


"yyyy. Mm.dd g´at´hh:mm:ss z ",


"EEE, MMM d,´´yy",


"h:mm a",


"H:mm:ss:sss",


"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,


Boxlayout.page_axis));


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);


　　 }


}