MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál stáhnout pdf (Strana 222)

9 Managing Application-Defined Data

9-10

functions setappdata, getappdata, isappdata, and rmappdata to manage

application data.

See “Application Data” on page 9-4 for more information about application

data.

Application Data Example: Passing Data Between a Slider and an Edit Text

Box

The previous topic, “GUI Data Example: Passing Data Between a Slider and an

Edit Text Box” on page 9-7, used GUI data to initialize and maintain an error

counter. This example shows you how to do the same thing using application

data. Refer to the previous topic for details of the example.

1 Define the error counter in the opening function. Add the following code to

the opening function. This code first creates a structure

slider_data, then

assigns it to the named application data

slider. Because this code appears

in the opening function, using

hObject associates the application data with

the figure.

slider_data.number_errors = 0;

setappdata(hObject,'slider',slider_data);

2 Set the edit text value from the slider Callback callback. Add this statement

to the slider

Callback.

set(handles.edit1,'String',...

num2str(get(handles.slider1,'Value')));

3 Set the slider value from the edit text Callback callback. Add this code to

the edit text

Callback. It assumes the figure’s Tag property is figure1.

To update the number or errors, the code must first retrieve the named

application data

slider, then increment the count. It then saves the

application data and displays the new error count.

val = str2double(get(hObject,'String'));

% Determine whether val is a number between 0 and 1

if isnumeric(val) & length(val)==1 & ...

val >= get(handles.slider1,'Min') & ...

val <= get(handles.slider1,'Max')

set(handles.slider1,'Value',val);

else

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MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál Strana 222