Spinner (computing)

A spinner is a graphical widget in a GUI, typically oriented vertically, with which a user may adjust a value in an adjoining text box by either clicking on an up or down arrow, or by holding the arrow down, causing the value in the text box to increase (if the up arrow is held down) or decrease (if the down arrow is held). In most cases as the button is held down, the spinner increases the speed at which the value of the spinner is increased or decreased, up to the maximum (or minimum) allowed value. Usually, the value of the spinner is displayed in a text box next to the spinner, allowing the user to use the spinner to adjust the value, or to type the value into the text box.

It is different from a scrollbar in that a spinner is typically used to adjust a value without changing the format of the display or the other information on the screen.

For programmers

Spinner is a composed GUI element. Its purpose is to influence a data element. It is (or should be) positioned together with the data it influences. The influence is usually an increase/decrease of some value. Therefore it is usually accompanied by 2 buttons - 2 arrows (from 3 cases - increase, decrease, do nothing) as symbol of that movement (change) of the influenced data.

The name "spinner" comes from the act of moving (although it can go far beyond this simple 2 buttons design).who

Spinner is special case of scrollbar.

crollbar

Scrollbar is a GUI element which represents (constant) interval interval_1 inside of another (constant) interval interval_2.

Values of interval_1 are subset of interval_2 . Second interval fully contains the first one.

You may imagine it as a window showing some large text_file, which does not fit entirely on screen. You have some screen resolution and therefore ability to show some limited span of text on screen. You would like to jump into the middle or arbitrary position. File would be arbitrary big. You might not know size of a file and/or do not know/want to specify position by keyboard (percentage). Given that you need a widget to handle it. You need to represent a whole file and some shown area plus you need to arbitrary change the position of viewed area of text file. Solution would be to use two rectangles (mental model of a file + screen).

Also it is usually accompanied with 2 buttons (3 states - nothing, move up, move down) which help to precise the movement.

Difference between scrollbar and spinner

Spinner does not show indication of value it influences - value is shown nearby. Therefore it would just be redundant information.

External links

* [http://ajax.asp.net/ajaxtoolkit/NumericUpDown/NumericUpDown.aspx ASP.NET AJAX Control Toolkit] NumericUpDown Demonstration