MATLAB Creating Graphical User Interfaces

12 Manage Application-Defined Data

Share Data Among Callbacks

In this section...

“Overview of Data Sharing Techniques” on page 12- 2

“Store Data in UserData or Other Object Properties” on page 12- 3

“Store Data as Application Data” on page 12- 4

“Create Nested Callback Functions (Programmatic UIs)” on page 12- 5

“Store Data Using the guidata Function” on page 12- 6

“Sharing Data Among Multiple GUIDE UIs” on page 12- 9

Overview of Data Sharing Techniques

Many UIs contain interdependent controls, menus, and graphics objects. Since each

callback function has its own scope, you must explicitly share data with those parts of

your UI that need to access it. The table below describes several different methods for

sharing data within your UI.

Method Description Requirements and Trade-Offs

“Store Data in

UserData or

Other Object

Properties” on

page 12- 3

Use dot syntax,

object.property, to store or

retrieve the value of an object

property.

All UI components have a

UserData property that can store

any MATLAB data.

• Requires access to the
  component to set or retrieve
  the properties.


• UserData holds only one
  variable at a time, but you
  can store multiple values as a
  struct array or cell array.

“Store Data

as Application

Data” on page

12-4

Associate data with a specific

component using the setappdata

function. You can access it later

using the getappdata function.

• Requires access to the
  component to set or retrieve
  the application data.


• Can share multiple variables.
  “Create Nested
  Callback
  Functions
  (Programmatic

Nest your callback functions

inside your main function. This

gives your callback functions

access to all the variables in the

main function.

• Requires callback functions to
  be coded in the same file as the
  main function.


• Not recommended for GUIDE
  UIs.