MATLAB: How to Move a Slider- bar when push button presses in GUI

auto move sliderMATLABslider as progress bar

There are two buttons one is forward and another backward,When forward button presses slider should start moving forward if backward buttons press slider should move backward direction.kindly suggest your ideas to implement this functionality in GUI.

Best Answer

Guide or app designer?

The slider property 'Value' determines the position of the slider bar. The value must be between the slider limits.

To move the slider when the pushbutton is pressed, the pushbutton callback function needs to change the value property of the slider. Add to the current value to move it forward. Subtract from it to move backward.

In guide, the code for the forward button might include something like this (untested)

sVal = get(handles.slider1,'Value');
set(handles.slider1,'Value',sVal+2);

In app designer, it might include this

app.slider1.Value = app.slider1.Value + 2;

Of course you'll want to include a check that only adjusts the value if the result is within the slider limits. You'll also want to set the amount you change Value to meet your needs.

Related Solutions

MATLAB: Control image transparency with a slider- appDesigner

This should get you started.

Two images are plotted on top of each other. A slider is added that sets the AlphaData of the top image.

% Create a figure with two images overlayed 
fig = uifigure('HandleVisibility','on'); 
[X,cmap] = imread('corn.tif');
imshow(X,cmap);
hold on
[X2,map] = imread('peppers.png');
img2 = imshow(X2,map);
% Create a GUI with a slider that controls the 'AlphaData' value of the currently selected object
sld = uislider(fig,'Position',[50,50,300,3],'Value',1,'Limits',[0,1],...
    'ValueChangingFcn', @(sld,event)changeTransparencyFcn(sld,event,img2),...
    'BusyAction', 'cancel');
% set the slider properties such as position etc....
% % https://www.mathworks.com/help/matlab/ref/uislider.html
function changeTransparencyFcn(~, event, hobj)
% hobj is the image object handle
set(hobj,'AlphaData', event.Value)
drawnow limitrate
end

Changes made to improve answer on Feb 9, 2021.

MATLAB: Slider for march chart

Lev - why in your SliderValueChanged callback are you overwriting the Slider with its value? I suggest that you remove this function (or at least the code inside of it)

function SliderValueChanged(app, event)
    % app.Slider = app.Slider.Value;   % <----- this isn't necessary and is dangerous!
end

As for the error, it is telling you that you are trying to index into an array with something other than a positive integer or (0 or 1) logical value. I suspect that the slider value is NOT an integer so you will need to ask your self how to convert this number into a valid index for the arrays. For example, your code might look like

function GPSMenuSelected(app, event)
        gps1=[app.x;app.y];
        plot(app.UIAxes,app.x,app.y,'LineWidth',2);
        hold on
        
        sliderValue = ceil(app.Slider.Value);    % <--- round up to the nearest integer
        if sliderValue >= 1 && sliderValue <= length(app.x)
            plot(app.UIAxes,app.x(sliderValue),app.y(sliderValue),'b--o',...
            'LineWidth',6);
        end
        hold off
end

I don't know if that is valid for you so please validate before trying it out.

Best Answer

Related Solutions

MATLAB: Control image transparency with a slider- appDesigner

MATLAB: Slider for march chart

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