| State model for buttons.
This model is used for regular buttons, as well as check boxes
and radio buttons, which are special kinds of buttons. In practice,
a button's UI takes the responsibility of calling methods on its
model to manage the state, as detailed below:
In simple terms, pressing and releasing the mouse over a regular
button triggers the button and causes and ActionEvent
to be fired. The same behavior can be produced via a keyboard key
defined by the look and feel of the button (typically the SPACE BAR).
Pressing and releasing this key while the button has
focus will give the same results. For check boxes and radio buttons, the
mouse or keyboard equivalent sequence just described causes the button
to become selected.
In details, the state model for buttons works as follows
when used with the mouse:
Pressing the mouse on top of a button makes the model both
armed and pressed. As long as the mouse remains down,
the model remains pressed, even if the mouse moves
outside the button. On the contrary, the model is only
armed while the mouse remains pressed within the bounds of
the button (it can move in or out of the button, but the model
is only armed during the portion of time spent within the button).
A button is triggered, and an ActionEvent is fired,
when the mouse is released while the model is armed
- meaning when it is released over top of the button after the mouse
has previously been pressed on that button (and not already released).
Upon mouse release, the model becomes unarmed and unpressed.
In details, the state model for buttons works as follows
when used with the keyboard:
Pressing the look and feel defined keyboard key while the button
has focus makes the model both armed and pressed. As long as this key
remains down, the model remains in this state. Releasing the key sets
the model to unarmed and unpressed, triggers the button, and causes an
ActionEvent to be fired. |
