MATLAB: Get mouse down and mouse up events from slider

Question

I am implementing (in R2016a) a continuous slider using a listener as follows:

sld = uicontrol('Style', 'slider');
sld.addlistener('ContinuousValueChange', @(src, evt) callbk(src, evt));

What I also want to do is to have callbacks when the mouse is first clicked on the slider and then when it is released. I can't find any appropriate events to do this in the uicontrol class.

Does anyone have suggestions?

Answer 1

The standard callback of the slider is called, when the mouse is released:

function main
sld = uicontrol('Style', 'slider', 'Callback', {@callbk, 'released'});
sld.addlistener('ContinuousValueChange', @(h, e) callbk(h, e, 'moved'));
end
function callbk(SliderH, EventData, Event)
disp(Event)
end

The WindowButtonDownFcn does not trigger, when the mouse is over the slider.

Then Java helps:

function main
hSlider    = uicontrol('style','slider');
jScrollBar = findjobj(hSlider);
jScrollBar.AdjustmentValueChangedCallback = @(h,e) callbk(h, e, 'moved');
jScrollBar.MousePressedCallback           = @(h,e) callbk(h, e, 'clicked');
jScrollBar.MouseReleasedCallback          = @(h,e) callbk(h, e, 'released');
end
function callbk(SliderH, EventData, Event)
disp(Event)
end

With FEX: findjobj