guidata (MATLAB Functions)

Store or retrieve application data

Syntax

guidata(object_handle, data)
data = guidata(object_handle)

Description

guidata(object_handle,data) stores the variable data in the figure's application data. If object_handle is not a figure handle, then the object's parent figure is used. data can be any MATLAB variable, but is typically a structure, which enables you to add new fields as requred.

Note that there can be only one variable stored in a figure's application data at any time. Subsequent calls to guidata(object_handle,data) overwrite the previously created version of data. See the Examples section for information on how to use this function.

data = guidata(object_handle) returns previously stored data, or an empty matrix if nothing has been stored.

guidata provides application developers with a convenient interface to a figure's application data:

You do not need to create and maintain a hard-coded property name for the application data throughout your source code.
You can access the data from within a subfunction callback routine using the component's handle (which is returned by gcbo), without needing to find the figure's handle.

guidata is particularly useful in conjunction with guihandles, which creates a structure in the figure's application data containing the handles of all the components in a GUI.

Examples

In this example, guidata is used to save a structure on a GUI figure's application data from within the initialization section of the application M-file. This structure is initially created by guihandles and then used to save additional data as well.

% create structure of handles
handles = guihandles(figure_handle); 
% add some additional data
handles.numberOfErrors = 0; 
% save the structure
guidata(figure_handle,handles)

You can recall the data from within a subfunction callback routine and then save the structure again:

% get the structure in the subfunction
handles = guidata(gcbo);
handles.numberOfErrors = handles.numberOfErrors + 1;
% save the changes to the structure
guidata(gcbo,handles)

gtext guide