The following code shows how to create a simple assistive
technology that can monitor events on the system event queue and
interface with accessible components. The example consists of one class,
AssistiveExample. This class creates
a small window containing two labels and five checkboxes, which are
repeatedly updated when the mouse comes to rest over an accessible
component for longer than half a second.
Note that while using 1.2 or higher accessibility, we have to
check to see if the GUI is ready for us to start firing
accessibility-related commands. We do this by checking the
EventQueueMonitor.isGUIInitialized( ) method.
This method returns a
indicating whether the GUI will accept accessibility commands. If it
does, then we’re fine. If it doesn’t, then we must register ourselves to
be notified when the GUI becomes available. This uses the
GUIInitializedListener interface, which we
To use the
class, simply create a new
AssistiveExample object from an existing
application. The constructor creates a frame and makes it visible. For
an example, check the source of the
BigExample class in the online code files for
Finally, note that we have a single button in our assistive example that performs the first action reported by the accessible context. You can use the Tab key to bring this button into focus while pointing with the mouse, then press the space bar to fire the action.
// AssistiveExample.java ...