Alan Cooper

to minimize mouse movement

The most basic entry control is a text edit field. Like selection controls, entry controls represent nouns to the application. Because a combo box contains an edit field, some combo box variants qualify as entry controls too. Also, any control that lets users enter a numeric value is an entry control. Because they allow users to set numeric values, controls such as spinners, gauges, sliders, and knobs fit in this category.

Conversely, a simple text field can accept any keyboard character the user types into it. This open-ended entry idiom is an example of an unbounded entry control. With an unbounded entry control, it can be easy for users to enter values that are invalid for the application. The application may subsequently reject the value, of course, but users can still enter it.

Any control that restricts the available set of values that the user can enter is a bounded entry control. A slider that moves from 1 to 100, for example, is bounded.

To be a bounded control, it needs to clearly communicate, preferably visually, the acceptable data boundaries to the user. A text field that rejects the user’s input after he enters it is not a bounded control. It is a rude control.

A much better scheme is to use a bounded control that automatically limits the input to 4, 5, 6, 7, or 8. If the bounded set of choices is composed of text rather than numbers, you can still use a bounded slider (sometimes called a trackbar), combo box, or list box.

Spinner controls are a common form of numeric entry control that permit data entry using the mouse, keyboard, or finger.

On iOS they’re called steppers and have plus or minus buttons side-by-side, making them much easier to actuate with fingers.

If the user wants to make a large change in one action or enter a precise setting, he can use the edit field portion for direct text entry. The arrow button portion of the control embodies bounding, whereas the edit field portion does not.

Dials and sliders are idioms borrowed directly from Mechanical-Age metaphors of rotating knobs and sliding levers. Dials are very space-efficient. Both can do a nice job of providing visual feedback about settings, as shown