MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál stáhnout pdf (Strana 221)

Sharing Data Among a GUI’s Callbacks

9-9

3 Set the slider value from the edit text Callback callback. The edit text

Callback sets the slider’s value to the number the user types in, after

checking to see if it is a single numeric value between 0 and 1. If the value

is out of range, then the error count is incremented and the edit text displays

a message telling the user how many times they have entered an invalid

number.

val = str2double(get(handles.edit1,'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

% Increment the error count, and display it.

handles.number_errors = handles.number_errors+1;

guidata(hObject,handles); % store the changes

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

['You have entered an invalid entry ',...

num2str(handles.number_errors),' times.']);

end

If the user types a number between 0 and 1 in the edit box and then presses

Enter or clicks outside the edit box, the Callback sets handles.slider1 to the

new value and the slider moves to the corresponding position.

If the entry is invalid — for example,

2.5 — the GUI increments the value of

handles.number_errors and displays a message like the following in the edit

text box:

Application Data

Application data can be associated with any object – a component, menu, or the

figure itself. To access application data, a callback must know the name of the

data and the handle of the component with which it is associated. Use the

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MATLAB SIMULINK 7 - GRAPHICAL USER INTERFACE Uživatelský manuál Strana 221