MATLAB: Display Value of a Slider in a text box without GUIDE

slider

Im struggling to find informations about how to display Data on a GUI without GUIDE.

More specificaly I have a slider 0->1 that I use to set my Threshold value (Image processing). I want the User to be able to see which value the slider is currently set to and changes brought to it.

There is no error Code but the value isnt showing up/ getting updated (Stays at 0)

These are fragments of my Code, please tell me if you need to see the whole thing:

fig = figure('Visible', 'on','Position',[0,0,1715,895], ...
           'Name', 'Projekt Matlab Workshop','Numbertitle','off', 'MenuBar', 'none')
       
           %... GUI Elements
           
           slider = uicontrol('Style','slider','Min',0,'Max',1,'Value',0.5,...                  
            'SliderStep',[0.025 0.05],'Position',[685,205,350,35]);
        
           % ... Labels
           
           lbl_schwellwertAnzeige = uicontrol('Style','text','String',num2str(get(slider, 'Value')),...
            'Position',[1040,150,10,30], 'FontSize', 11);

Best Answer

If you want the slider to update something (text, plot, anything) as it moves, then you will need to add a listener:

https://www.mathworks.com/help/matlab/ref/handle.addlistener.html

Here is a complete working solution for pre-R2014b MATLAB, that updates an edit box while dragging the slider:

ht = uicontrol('style','edit','Position',[10,60,40,40]);
hs = uicontrol('style','slider','Position',[10,10,400,20]);
fun = @(o,e)set(ht,'String',num2str(get(e,'NewValue')));
addlistener(hs, 'Value', 'PostSet',fun);

And it looks like this:

For post R2014b use this::

fun = @(~,e)set(ht,'String',num2str(get(e.AffectedObject,'Value')));

Related Solutions

MATLAB: Syncing both sliders and edit boxes

set( handles.Slider1, 'Value', str2double(get(handles.Editbox1, 'String')) )

MATLAB: Update automatically edit box when user enters values in other edit boxes

isdapi - if you use the same callback function for each of your four edit boxes, and nest this function within your main code, then you can do the above. Try something like

 function myGui
     % create the figure
     figure('Position',[ 680   809   447   169]);
     % create the edit boxes
     %Edit boxes where the user inserts or changes data
     e0 = uicontrol('Style','edit','Position',[150 105 80 20],'String','15',...
                    'Callback', @updateTxtBox); %Default value, but user can change it.
     e1 = uicontrol('Style','edit','Position',[150 80 80 20],'Callback',@updateTxtBox);
     e2 = uicontrol('Style','edit','Position',[150 55 80 20],'Callback',@updateTxtBox);
     e3 = uicontrol('Style','edit','Position',[150 20 80 20],'Callback',@updateTxtBox);
     %Edit box that needs to be updated only when the user inputs data in the previous edit boxes.
     e4 = uicontrol('Style','edit','Position',[285 140 50 20],'Enable','off');
     % define the callback
     function updateTxtBox(object,eventdata)
        h1 = get(e1,'String'); 
        h2 = get(e2,'String');
        h3 = str2num(h1) + str2num(h2);
        v1 = str2num(get(e3,'String'));
        var = str2num(get(e0,'String'));
        v2 = num2str(v1*171233*((288+var)-0.00198*h3)^0.5/(288-0.00198*h3)^2.628);
        set(e4,'String',v2);
     end % updateTxtBox
 end  % myGui

Because updateTxtBox is nested within the myGui function, it has access to the local variables (i.e. handles) of the myGui function. Note that you could/should add some code to the callback to check for non-numeric strings, and that you could create e4 as a text control rather than an edit one.

Try the above and see what happens!

Best Answer

Related Solutions

MATLAB: Syncing both sliders and edit boxes

MATLAB: Update automatically edit box when user enters values in other edit boxes

Related Question