Swing Hacks

Create Custom Tool Tips #43

Chapter 6, Transparent and Animated Windows

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HACK

H A C K

#43

Create Custom Tool Tips

Hack #43

Replace the standard rollover tool tip with an attractive custom version,

including a border and rounded corners.

Every Swing component can have a tool tip, a little snippet of explanatory

text that pops up when you let your mouse cursor linger over the compo-

nent. These tool tips are often useful, but they usually look quite boring.

This hack shows how to create visually interesting tool tips with a custom

subclass.

In Swing, all tool tips are instances of the

JToolTip class. To create your own

version, you need only subclass

JToolTip and override the paintComponent( )

method. In this hack, we’ll create a tool tip with a rectangle that has a bev-

eled border and a white background. The actual drawing can be taken care

of with a few Java2D drawing commands. Example 6-4 is the code to draw

the tool tip’s background and border.

Example 6-4. A nice-looking tool tip

class CustomToolTip extends JToolTip {

public void paintComponent(Graphics g) {

// create a round rectangle

Shape round = new RoundRectangle2D.Float(4,4,

this.getWidth( )-1-8,

this.getHeight( )-1-8,

15,15);

// draw the white background

Graphics2D g2 = (Graphics2D)g;

g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,

RenderingHints.VALUE_ANTIALIAS_ON);

g2.setColor(Color.white);

g2.fill(round);

// draw the gray border ...