MATLAB: Apart from main program, executing function continuously GUI matlab.

guimatlab gui

Dear experts,

this is Carlos. Now, I'm programming a GUI in Matlab.

In this GUI, I have some buttons and static texts. Particularly, I would like to change the text of a static box continuously, i.e., regardless the changes made in the main program.

Concretely, this static box takes the values from other hardware. The values obtained from this hardware have to be shown constantly. Simultaneously this static box shows the values from the hardware, I would like to press other buttons and carry out other functions.

The concept I look for, probably, is a kind of parallel programming. However, I think an easier solution should have.

Thank you in advance.

Carlos.

Best Answer

You can use a timer to update the GUI. Store the handle of the GUI object to be affected in the timer's UserData, such that it is available in the TimerFcn.

function myGUI
FigH   = figure;
TextH  = uicontrol('Style', 'Text', 'Position', [10, 10, 200, 24]);
TimerH = timer('UserData', TextH, 'TimerFcn', @myTimerFcn, 'Period', 1, ...
      'ExecutionMode', 'fixedRate');
drawnow;
start(TimerH);
end
function myTimerFcn(TimerH, EventData)
TextH = get(TimerH, 'UserData');
set(TextH, 'String', datestr(now, 0));
drawnow;  % Thanks Walter
end

Store the handle of the timer in the figure's UserData or ApplicationData (e.g. by handles.timerH = timer(...), such that it can be deleted in the CloseRequestFcn of the figure automatically.

Related Solutions

MATLAB: Executing two timer functions continuously. GUI.

Using global variables is a bad idea in general. If you see a way to avoid them, do this.

You did not mention, what is not working. Do you get an error message? Is the timer function entered?

Why do you calculate the values.

distancia = Guardar_pos(TextH);

and

distancia_fija = Guardar_pos3(TextH2);

when the variables are not used at all? What is "Guardar_pos" and "Guarder_pos3"?

If you define the TimerFcn as "@myTimerFcn2", it is called with 2 inputs: The handle of the timer and the EventData struct. Then requesting 4 inputs is not smart, although it is not an error, when the not provided inputs are not used in the function:

function myTimerFcn2(TimerH2,eventData,handles,hObject)
% Better:
function myTimerFcn2(TimerH2,eventData)

There is no need for a drawnow after creating a timer object. But after setting a string, drawnow is required to see the changes. A simplified timer callback:

function myTimerFcn2(TimerH2,eventData)
global distance2 flag_tracker
TextH2 = get(TimerH2, 'UserData');
if flag_tracker == 1
    % distancia_fija = Guardar_pos3(TextH2);   % Is this needed at all?
    % pause(0.5)
    set(TextH2, 'String', num2str(distance2))
else
    set(TextH2, 'String', 'Measuring...');
end
drawnow;

MATLAB: How to implement a timer function that updates a static text box within the GUI

You need to pass handles into the callback

@(t,e)timerCallback(t,e,handles)

Also, why aren't you using app designer?

doc appdesigner

Best Answer

Related Solutions

MATLAB: Executing two timer functions continuously. GUI.

MATLAB: How to implement a timer function that updates a static text box within the GUI

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