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Using Swing Components
How to Use HTML in Swing Components
Many Swing components display a text string
as part of their GUI.
By default, a component's text is displayed
in a single font and color,
all on one line.
You can determine the font and color of a component's text
by invoking the component's setFont and setForeground
methods, respectively.
For example, the following code
creates a label and then sets its font and color:
label = new JLabel("A label");
label.setFont(new Font("Serif", Font.PLAIN, 14));
label.setForeground(new Color(0xffffdd));
If you want to mix fonts or colors within the text,
or if you want formatting such as multiple lines,
you can use HTML.
HTML formatting can be used in all Swing buttons, menu items,
labels, tool tips, and tabbed panes,
as well as in components such as trees and tables
that use labels to render text.
To specify that a component's text has HTML formatting,
just put the <html> tag at the beginning of the text,
then use any valid HTML in the remainder.
Here is an example of using HTML in a button's text:
button = new JButton("<html><b><u>T</u>wo</b><br>lines</html>");
Here is the resulting button.
An Example: HtmlDemo
An application called HtmlDemo
lets you play with HTML formatting
by setting the text on a label. You can find the entire code for this program in
HtmlDemo.java.
Here is a picture of the HtmlDemo
example.
Try This:
- Click the Launch button
to run HtmlDemo using
Java™ Web Start
(download JDK 6).
Alternatively, to compile and run the example yourself,
consult the example index.
-
Edit the HTML formatting in the text area at the left
and click the "Change the label" button. The
label at the right shows the result.
-
Remove the <html> tag from the text area on the left.
The label's text is no longer parsed as HTML.
Example 2: ButtonHtmlDemo
Let us look at another example that uses HTML.
ButtonHtmlDemo adds font, color, and other text formatting
to three buttons. You can find the entire code for this program in
ButtonHtmlDemo.java. Here is a picture of the ButtonHtmlDemo
example.
Click the Launch button
to run ButtonHtmlDemo
using
Java™ Web Start
(download JDK 6).
Alternatively, to compile and run the example yourself, consult the
example index.
The left and right buttons have multiple lines and text styles
and are implemented using
HTML. The middle button, on the other hand,
uses just one line, font, and color, so it does not
require HTML.
Here is the code that specifies
the text formatting for these three buttons:
b1 = new JButton("<html><center><b><u>D</u>isable</b><br>"
+ "<font color=#ffffdd>middle button</font>",
leftButtonIcon);
Font font = b1.getFont().deriveFont(Font.PLAIN);
b1.setFont(font);
...
b2 = new JButton("middle button", middleButtonIcon);
b2.setFont(font);
b2.setForeground(new Color(0xffffdd));
...
b3 = new JButton("<html><center><b><u>E</u>nable</b><br>"
+ "<font color=#ffffdd>middle button</font>",
rightButtonIcon);
b3.setFont(font);
Note that we have to use a <u> tag to cause
the mnemonic characters "D" and "E" to be underlined in
the buttons that use HTML. Note also that when
a button is disabled, its HTML text unfortunately
remains black, instead of becoming gray.
(Refer to
bug #4783068 to see if this situation changes.)
This section discussed how to use HTML in ordinary,
non-text components.
For information on components whose primary purpose is formatting text,
see
Using Text Components.
