Create slider with dynamic range based on user input matlab gui - matlab

Question

Hi I have a quick question on how to solve this issue. Basically I would like to take the inputs from two edit text boxes and specify them as the min and max of the sliders range. I don't have a problem doing this but as soon as the min is entered the slider disappears because the min is now above the default slider value, which is 0. I understand that the error is because the value is no longer in the range of the min and max, and I want to fix this by updating the value to be above the min in the call back function for the min/max input text boxes. Is there a way I can update the default value to be above min so I can get past this error and actually use the slider?
Warning: 'slider' control cannot have a 'Value' outside of 'Min'-'Max' range
Control will not be rendered until all of its parameter values are valid
Here is what I have tried to do in the call back to the edit box that gets user input for the minimum for the slider:
function input_min_Callback(hObject, eventdata, handles)
value_min=str2double(get(hObject, 'String'));
if value_min > sliderValue_default
set(handles.Input_Transverse_Shear_Layer1, 'Value', value_min+1);
set(handles.Input_Transverse_Shear_Layer1, 'Min', value_min);
end
Any help would be greatly appreciated!
Thanks

Answer 1

Your code looks fine to me. You seem to be missing a guidata(hObject,handles)at the end to update the guidata so this could be the problem (unless it's there but you did not include it in your above snippet).
In any case here is a bit of code that looks very much like yours and works fine. Try it out so you might see what is wrong with yours...
function UpdateSliderMin(~)
clc
clear
close all
%// Create GUI elements and set default slide value
hFig = figure('Position',[200 200 200 300]);
sliderValue_default = 0;
handles.Slider = uicontrol('style', 'Slider', 'Min', -5, 'Max', 10, 'Value',sliderValue_default, 'Units','normalized','position', [0.08 0.3 0.08 0.6], 'callback', #(s,e) SliderCbk);
handles.Text_min = uicontrol('Style','text','String','Min','position', [60 230 40 20]);
handles.Edit_min = uicontrol('Style','edit','String',num2str(get(handles.Slider,'min')),'position', [100 230 40 20],'Callback',#(s,e) MinCallback);
handles.Text_max = uicontrol('Style','text','String','Max','position', [60 180 40 20]);
handles.Edit_max = uicontrol('Style','edit','String',num2str(get(handles.Slider,'max')),'position', [100 180 40 20]);
handles.Text_val = uicontrol('Style','text','String','value','position', [60 130 40 20]);
handles.Edit_val = uicontrol('Style','edit','String',num2str(get(handles.Slider,'value')),'position', [100 130 40 20]);
guidata(hFig,handles)
%// Callback of the edit box for the min value
function MinCallback
value_min=str2double(get(handles.Edit_min, 'String'));
if value_min > sliderValue_default
set(handles.Slider, 'Value', value_min+1);
set(handles.Slider, 'Min', value_min);
set(handles.Edit_val,'String',get(handles.Slider, 'Value'));
end
guidata(hFig,handles)
end
%// Slider callback. Just to check the value is updated correctly
function SliderCbk
CurrentValue = get(handles.Slider,'Value');
set(handles.Edit_val,'String',num2str(CurrentValue));
guidata(hFig,handles)
end
end
Screenshot of the initial GUI:
And after setting the minimum value to 5, which is above the current value of the slider:
the current value is updated to 6 as expected.
Hope that helps!