Creating Graphical User Interfaces

Some Commonly Used Properties

As examples, this section describes four important and commonly used properties of user interface control components: Tag, Callback, String, and Value.

Tag

The Tag property is an identifier for the component. GUIDE assigns a value to the Tag property of every component you insert in your layout (e.g., pushbutton1) and then uses this string to name the callback associated with the Callback property (e.g., pushbutton1_Callback). You should change the Tag property to a more descriptive name, so that you can more easily identify the component's callback in the M-file. For example, if you add a push button that closes the GUI, you might set its tag to close_button.

GUIDE uses the Tag property to

• Construct the name of the generated callback (e.g., close_button_Callback) when you run or save the GUI
• Set corresponding callback properties to point to the callback.
• Add a field to the handles structure containing the handle of the object (e.g., handles.close_button)

Note    Since GUIDE uses the Tag property to name functions and structure fields, the tag you select must be a valid MATLAB variable name. Use isvarname to determine if the string you want to use is valid.

Callback

The Callback property specifies the callback that is executed in the GUI M-file when a user activates the component.

String

The String property contains text for the component. The following are examples:

• For buttons, check boxes, list boxes, edit text, and static text, the String text is displayed on or next to the component.
• For an edit text, the String property contains a list of strings that is displayed in the text box. When a user edits the text, the String property is updated.

Note    Except for the edit text, if the String you specify does not fit in the component, the text is clipped in the active GUI and an ellipsis (...) is appended. However, the ellipsis does not appear in the GUIDE Layout Editor.

Value

The Value property contains a numerical value for the component, which must lie in the range specified by the Max and Min properties. The following are examples:

• For radio buttons and check boxes, Max and Min are set to 1 and 0, respectively, by default. The Value property is set to 1 when the radio button or check box is selected, and 0 when it is cleared.
• When a user drags a slider, the Value is set to a number between Max and Min corresponding to the location of the slider button.

What Properties Do I Need to Set?

Setting Properties for Some Specific Components

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