Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Need to display a JSeparator in a JComboBox

Posted on 2008-10-02
5
Medium Priority
?
969 Views
Last Modified: 2013-12-17
I use the following comboBox to display a set of strings to the operator, that will
grey out the third selection (see "Text Line 3", false)...
My problem is that the separator does not display correctly - it seems to produce the ToString()
results in the line of text. What can I do to display the horizontal separator in the comboBox list?

Thanks

Object[] items = { 	new ComboItem<String>(new String("Text Line 1"), true),
					new ComboItem<String>(new String("Text Line 2"), true), 
					new ComboItem<JSeparator>(new JSeparator(), true),
					new ComboItem<String>(new String("Text Line 3"), false), 
				
				
		selectionComboBox = new JComboBox(items);
		selectionComboBox.setRenderer(new ComboRenderer());
		selectionComboBox.addActionListener(new ComboListener(selectionComboBox));
		selectionComboBox.setBounds(140, 101, 254, 25);
		selectionComboBox.setMaximumRowCount(14);
		getContentPane().add(selectionComboBox);
		
		// CellRenderer
		class ComboRenderer extends JLabel implements ListCellRenderer {
		private static final long serialVersionUID = 1L;
 
		public ComboRenderer() {
			setOpaque(true);
			setBorder(new EmptyBorder(1, 1, 1, 1));
		}
 
		public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected,
				boolean cellHasFocus) {
			if (isSelected) {
				setBackground(list.getSelectionBackground());
				setForeground(list.getSelectionForeground());
			} else {
				setBackground(list.getBackground());
				setForeground(list.getForeground());
			}
			if (!((CanEnable) value).isEnabled()) {
				setBackground(list.getBackground());
				setForeground(UIManager.getColor("Label.disabledForeground"));
			}
			setFont(list.getFont());
			setText((value == null) ? "" : value.toString());
			return this;
		}
	}
 
	/**
	 * Handles the combo box selection
	 *
	 */
	class ComboListener implements ActionListener {
		JComboBox combo;
		Object currentItem;
 
		ComboListener(JComboBox combo) {
			this.combo = combo;
			combo.setSelectedIndex(0);
			currentItem = combo.getSelectedItem();
		}
 
		public void actionPerformed(ActionEvent e) {
			Object tempItem = combo.getSelectedItem();
			if (!((CanEnable) tempItem).isEnabled()) {
				combo.setSelectedItem(currentItem);
			} else {
				currentItem = tempItem;
			}
		}
	}
 
	/**
	 * The item displayed by the combo box
	 *
	 * @param <T>
	 */
	class ComboItem<T> implements CanEnable {
		T obj;
		boolean isEnable;
 
		ComboItem(T obj, boolean isEnable) {
			this.obj = obj;
			this.isEnable = isEnable;
		}
 
		ComboItem(T obj) {
			this(obj, true);
		}
 
		public boolean isEnabled() {
			return isEnable;
		}
 
		public void setEnabled(boolean isEnable) {
			this.isEnable = isEnable;
		}
 
		public String toString() {
			return obj.toString();
		}
 
		public T getValue() {
			return obj;
		}
	}

Open in new window

0
Comment
Question by:dbCnc
  • 3
  • 2
5 Comments
 
LVL 37

Expert Comment

by:zzynx
ID: 22633653
>> My problem is that the separator does not display correctly - it seems to produce the ToString()

Sure. That's what you told it to do:

setText((value == null) ? "" : value.toString());
0
 

Author Comment

by:dbCnc
ID: 22635643
xxynk,

Thanks for the reply - but it's still not obvious to me how to display the separator as a line.

==>Sure. That's what you told it to do:
==>setText((value == null) ? "" : value.toString());

Perhaps I can test the obj T in ComboItem, and do something different from what is returned in line 93,
but I want a solid line to appear - of the correct length for the displayed ComboBox.

Could you elaborate?

Thanks again...
0
 
LVL 37

Accepted Solution

by:
zzynx earned 2000 total points
ID: 22677209
0
 

Author Closing Comment

by:dbCnc
ID: 31504684
ZZYNX,

The first solution was exactly what I was looking for. I had gone through quite a few examples from that site - but never found that one.

I added my enable/disable code to the listeners, and I'm all set...

Thanks Again
0
 
LVL 37

Expert Comment

by:zzynx
ID: 22679280
Thanx 4 axxepting
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Rules and regulations were devised in order to maintain the integrity of a system. However, interpretation of rules can be quite tricky.
Want to know how to use Exchange Server Eseutil command? Go through this article as it gives you the know-how.
With the power of JIRA, there's an unlimited number of ways you can customize it, use it and benefit from it. With that in mind, there's bound to be things that I wasn't able to cover in this course. With this summary we'll look at some places to go…
How to fix incompatible JVM issue while installing Eclipse While installing Eclipse in windows, got one error like above and unable to proceed with the installation. This video describes how to successfully install Eclipse. How to solve incompa…
Suggested Courses

824 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question