MATLAB Function Reference

uicontrol

Create user interface control object

Syntax

handle = uicontrol(parent)
handle = uicontrol(...,'PropertyName',PropertyValue,...)

Description

uicontrol creates uicontrol graphics objects (user interface controls). You implement graphical user interfaces using uicontrols. When selected, most uicontrol objects perform a predefined action. MATLAB supports numerous styles of uicontrols, each suited for a different purpose:

• Check boxes
• Editable text
• Frames
• List boxes
• Pop-up menus
• Push buttons
• Radio buttons
• Sliders
• Static text
• Toggle buttons

Check boxes generate an action when clicked on. These devices are useful when providing the user with a number of independent choices. To activate a check box, click the mouse button on the object. The state of the device is indicated on the display.

Editable text boxes are fields that enable users to enter or modify text values. Use editable text when you want text as input.

On Microsoft Windows systems, if an editable text box has focus, clicking on the menu bar does not cause the editable text callback routine to execute. However, it does cause execution on UNIX systems. Therefore, after clicking on the menu bar, the statement

get(edit_handle,'String')

does not return the current contents of the edit box on Microsoft Windows systems because MATLAB must execute the callback routine to update the String property (even though the text string has changed on the screen). This behavior is consistent with the respective platform conventions.

Frames are boxes that visually enclose regions of a figure window. Frames can make a user interface easier to understand by visually grouping related controls. Frames have no callback routines associated with them. Only uicontrols can appear within frames.

Frames are opaque, not transparent, so the order you define uicontrols is important in determining whether uicontrols within a frame are covered by the frame or are visible. Stacking order determines the order objects are drawn: objects defined first are drawn first; objects defined later are drawn over existing objects. If you use a frame to enclose objects, you must define the frame before you define the objects.

List boxes display a list of items (defined using the String property) and enable users to select one or more items. The Min and Max properties control the selection mode. The Value property indicates selected entries and contains the indices into the list of strings; a vector value indicates multiple selections. MATLAB evaluates the list box's callback routine after any mouse button up event that changes the Value property. Therefore, you may need to add a "Done" button to delay action caused by multiple clicks on list items. List boxes differentiate between single and double clicks and set the figure SelectionType property to normal or open accordingly before evaluating the list box's Callback property.

Pop-up menus open to display a list of choices (defined using the String property) when pressed. When not open, a pop-up menu indicates the current choice. Pop-up menus are useful when you want to provide users with a number of mutually exclusive choices, but do not want to take up the amount of space that a series of radio buttons requires. You must specify a value for the String property.

Push buttons generate an action when pressed. To activate a push button, click the mouse button on the push button.

Radio buttons are similar to check boxes, but are intended to be mutually exclusive within a group of related radio buttons (i.e., only one is in a pressed state at any given time). To activate a radio button, click the mouse button on the object. The state of the device is indicated on the display. Note that your code can implement the mutually exclusive behavior of radio buttons.

Sliders accept numeric input within a specific range by enabling the user to move a sliding bar. Users move the bar by pressing the mouse button and dragging the pointer over the bar, or by clicking in the trough or on an arrow. The location of the bar indicates a numeric value, which is selected by releasing the mouse button. You can set the minimum, maximum, and current values of the slider.

Static text boxes display lines of text. Static text is typically used to label other controls, provide directions to the user, or indicate values associated with a slider. Users cannot change static text interactively and there is no way to invoke the callback routine associated with it.

Toggle buttons are controls that execute callbacks when clicked on and indicate their state, either on or off. Toggle buttons are useful for building toolbars.

Remarks

The uicontrol function accepts property name/property value pairs, structures, and cell arrays as input arguments and optionally returns the handle of the created object. You can also set and query property values after creating the object using the set and get functions.

Uicontrol objects are children of figures and therefore do not require an axes to exist when placed in a figure window.

Properties

This table lists all properties useful for uicontrol objects, grouping them by function. Each property name acts as a link to a description of the property.

Property Name	Property Description	Property Value
Controlling Style and Appearance
BackgroundColor	Object background color	Value: ColorSpec Default: system dependent
CData	Truecolor image displayed on the control	Value: matrix
ForegroundColor	Color of text	Value: ColorSpec Default: [0 0 0]
SelectionHighlight	Object highlighted when selected	Value: on, off Default: on
String	Uicontrol label, also list box and pop-up menu items	Value: string
Visible	Uicontrol visibility	Value: on, off Default: on
General Information About the Object
Children	Uicontrol objects have no children
Enable	Enable or disable the uicontrol	Value: on, inactive, off Default: on
Parent	Uicontrol object's parent	Value: scalar figure handle
Selected	Whether object is selected	Value: on, off Default: off
SliderStep	Slider step size	Value: two-element vector Default: [0.01 0.1]
Style	Type of uicontrol object	Value: pushbutton, togglebutton, radiobutton, checkbox, edit, text, slider, frame, listbox, popupmenu Default: pushbutton
Tag	User-specified object identifier	Value: string
TooltipString	Content of object's tooltip	Value: string
Type	Class of graphics object	Value: string (read-only) Default: uicontrol
UserData	User-specified data	Value: matrix
Controlling the Object Position
Position	Size and location of uicontrol object	Value: position rectangle Default: [20 20 60 20]
Units	Units to interpret position vector	Value: pixels, normalized, inches, centimeters, points, characters Default: pixels
Controlling Fonts and Labels
FontAngle	Character slant	Value: normal, italic, oblique Default: normal
FontName	Font family	Value: string Default: system dependent
FontSize	Font size	Value: size in FontUnits Default: system dependent
FontUnits	Font size units	Value: points, normalized, inches, centimeters, pixels Default: points
FontWeight	Weight of text characters	Value: light, normal, demi, bold Default: normal
HorizontalAlignment	Alignment of label string	Value: left, center, right Default: depends on uicontrol object
String	Uicontrol object label, also list box and pop-up menu items	Value: string
Controlling Callback Routine Execution
BusyAction	Callback routine interruption	Value: cancel, queue Default: queue
ButtonDownFcn	Button press callback routine	Value: string
Callback	Control action	Value: string
CreateFcn	Callback routine executed during object creation	Value: string
DeleteFcn	Callback routine executed during object deletion	Value: string
Interruptible	Callback routine interruption mode	Value: on, off Default: on
UIContextMenu	Uicontextmenu object associated with the uicontrol	Value: handle
Information About the Current State
ListboxTop	Index of top-most string displayed in list box	Value: scalar Default: [1]
Max	Maximum value (depends on uicontrol object)	Value: scalar Default: object dependent
Min	Minimum value (depends on uicontrol object)	Value: scalar Default: object dependent
Value	Current value of uicontrol object	Value: scalar or vector Default: object dependent
Controlling Access to Objects
HandleVisibility	Whether handle is accessible from command line and GUIs	Value: on, callback, off Default: on
HitTest	Whether selectable by mouse click	Value: on, off Default: on

Examples

The following statement creates a push button that clears the current axes when pressed:

h = uicontrol('Style', 'pushbutton', 'String', 'Clear',...
    'Position', [20 150 100 70], 'Callback', 'cla');

You can create a uicontrol object that changes figure colormaps by specifying a pop-up menu and supplying an M-file name as the object's Callback:

hpop = uicontrol('Style', 'popup',...
       'String', 'hsv|hot|cool|gray',...
       'Position', [20 320 100 50],...
       'Callback', 'setmap');

The above call to uicontrol defines four individual choices in the menu: hsv, hot, cool, and gray. You specify these choices with the String property, separating the choices with the "|" character.

The Callback, in this case setmap, is the name of an M-file that defines a more complicated set of instructions than a single MATLAB command. setmap contains these statements:

val = get(hpop,'Value');
if val == 1
    colormap(hsv)
elseif val == 2
    colormap(hot)
elseif val == 3
    colormap(cool)
elseif val == 4
    colormap(gray)
end

The Value property contains a number that indicates the selected choice. The choices are numbered sequentially from one to four. The setmap M-file can get and then test the contents of the Value property to determine what action to take.

Object Hierarchy

See Also

textwrap, uimenu

uicontextmenu Properties

Uicontrol Properties