Button Description
A button is a visual screen element in a GraphicalUserInterface. The button allows the user to communcate a command to the computer. Buttons are usually square or round, with a text label in the center. Most buttons have a 3D look that makes them appear to be sticking out of the screen. A user activates the button by pressing and releasing it. Buttons are intuitive to users because they work like physical buttons (like on the front of your computer).
Example
An email sending program might have a button labeled SEND. After the text of an email message, the user can activate this button to tell the program that the email is ready to be sent.
Expected Behavior
Computer users today (in 2003) have certain expectations about the behavior of buttons:
- Visual Feedback: When the user presses on a button, it should immediately change its appearance. A 3D style button should appear to have sunken down into the screen. When the button is released, it should revert to its original appearance.
- Spring-Loaded: A button should always return to its original state when released. A button should not be used as a toggle device. The only time that a button can remain depressed is when the user's finger is pressing on it.
- Cancellation: A button should activate only when the user releases it. If the user's finger slides off a button without releasing it, the button should not activate but return to its unpressed state. A button may only activatet if the user's finger is in the region of the button when it is released.
Implementations
Please post implementations of button in various langauges.