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Message:

RE: Controlling the Layout of a disabled

Posted by Kishori Sharan on July 26, 2000 at 5:15 PM

Hi
I got another solution and it seems very easy. If you want to change the color of a JCombobox you have to write just one line of code.
UIManager.put ( "ComboBox.disabledForeground", Color.blue ) ;
This will make the color of all JComboBox in disabled state as blue. However, this doesn't work for a checkbox. For a checkbox when you change the property to make it disabled, its getBackGround ( ) method is called. getBackground ( )
method returns a Color object. Then darker ( ) method is called on that Color object to set the final disabled color. So you need to override the getBackground ( ) method of the JCheckBox to achieve this. I have done it in the follong example.

Thanx
Kishori
/////////////////////////////////////////////////////////////////////////////

import java.util.* ;
import javax.swing.*;
import java.awt.*;
import java.awt.event.* ;

/* This class is defined to be used in getBackground() method of MyJCheckBox
class. You may not need this class if you preffer defining inner class in that
method itself*/

class MyColor extends Color {
MyColor ( int r, int g, int b ) {
super ( r, g, b ) ;
}

public Color darker ( ) {
return Color.red ;
}

}

class MyJCheckBox extends JCheckBox {
public MyJCheckBox ( String s ) {
super ( s ) ;
}

/* When we disable the checkbox then the getBackground ( ) method on it is
called which returns a Color object. Then the darker ( ) method is called
on that Color method and the returned Color is used as the disabled color
for that checkbox */

public Color getBackground() {
if ( isEnabled() )
return super.getBackground();


Color base = super.getBackground();
return new MyColor(base.getRed(), base.getGreen(), base.getBlue()) ;

/* Uncomment the following and comment the above line, if you don't want
to define a new MyColor class

return new Color(base.getRed(), base.getGreen(), base.getBlue()){
public Color darker(){
return Color.blue;
}
}; */

}

}

public class H1 extends JApplet {

String[] str = { "Hello", "Thanx", "Bye" } ;

MyJCheckBox jcbx1 = new MyJCheckBox ( "Enabled" ) ;
MyJCheckBox jcbx2 = new MyJCheckBox ( "Disabled" ) ;
JComboBox jcmb1 = new JComboBox ( str ) ;

public void init ( ) {

Container cp = getContentPane () ;

cp.setLayout( new FlowLayout ( ) ) ;

/* Set the color for disabled combo box in UIManager. However, we cannot
do the same thing for a checkbox because UIManager is not used
to set the foreground color of a checkbox rather the getBackground
method is called and the darker of the color returned from getBackground
method is used */

UIManager.put ( "ComboBox.disabledForeground", Color.blue ) ;

jcbx2.setEnabled ( false ) ;
jcmb1.setEnabled ( false ) ;

cp.add ( jcbx1 ) ;
cp.add ( jcbx2 ) ;
cp.add ( jcmb1 ) ;

}
}