Swing Hacks

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Chapter 12, Miscellany

#90 Create Demonstrations with the Robot Class

HACK

H A C K

#90

Create Demonstrations with the Robot Class

Hack #90

Use the Robot class to control the mouse cursor and create interactive

software features.

One of the coolest things about Swing is that you can often use a class for

something completely different than what it was originally intended. The

java.awt.Robot class, for example, can move the mouse cursor programmat-

ically. This feature was originally intended for use by automated testing

tools (hence the name Robot), but I’ve found it very useful to demonstrate

software features by moving the mouse cursor through the same actions as

the user. Instead of just describing something in a help file, you can actually

show the user what to do—and this hack explains how.

I, Robot

To create a mouse animation, you need three things:

1. The ability to move the cursor

2. The start and end points of the animation

3. A way to smoothly interpolate the cursor position

The

java.awt.Robot class has a variety of methods for capturing program

state and controlling the user interface, including

Robot.mouseMove( ), which

allows you to move the mouse cursor programmatically.

The following code is the implementation of a method

moveMouse( ), which

takes three arguments: a starting component, an ending component, and a

duration for the animation (in milliseconds). Because most demonstrations

involve ...