MATLAB: In a callback, how to determine which mouse button was pressed to generate the callback

clicksdouble clickdoubleclickeventsMATLAB

I would like to determine, in a callback, which mouse button was pressed to generate the callback.

Best Answer

You can determine which mouse event has occurred by examining the 'SelectionType' property of the figure. The property can take the following values:

1. normal: left mouse button

2. extend: right mouse button on a 2-button mouse;

middle mouse button on a 3-button mouse

3. alt: left+right buttons on a 2-button mouse;

 right mouse button on a 3-button mouse

4. open:double mouse click

For example, you can see the values taken by executing the following:

figure;
set(gcf,'WindowButtonDownFcn', 'disp(get(gcf,''SelectionType''));');

Now click in the current figure to see the values displayed.

Related Solutions

MATLAB: How to make a push button respond to clicking with the right mouse button

There are two properties which can be used in conjunction to accomplish this.

One is the button's 'ButtonDownFcn' callback function. This callback function executes when pressing a mouse button on or near a UICONTROL object -- including when pressing the right mouse button.

The other property is the figure's 'SelectionType' property. This property indicates which kind of click was registered in the figure window -- including clicks on controls within the figure.

Putting these two together, you can define a 'ButtonDownFcn' callback for a push button which checks the figure's 'SelectionType' property to detect a right-click. An example is shown below. (In that example, the ANCESTOR function is used to get the figure's handle. If this is being done in a GUIDE-created GUI, this is unnecessary as the 'handles' structure already provides access to the figure's handle.)

function test
      uicontrol('Style', 'pushbutton', ...
                'ButtonDownFcn', @myCallback);
end
function myCallback(src, evt)
      figHandle = ancestor(src, 'figure');
      clickType = get(figHandle, 'SelectionType');
      if strcmp(clickType, 'alt')
          disp('right click action goes here!');
      end
end

MATLAB: Implementing listener and callback, infinite loop

Personally I always use addlistener syntax when adding a listener. I am not familiar with your syntax, but it seems it will still work. The 'See Listen for Changes to Property Values.' link takes you to a page where all the examples use addlistener, but since you are getting this error message I assume the two syntaxes are interchangeable.

Basically you need to just follow what the error tells you and add the 'SetObservable' attribute to your 'brand' property

e.g.

properties( SetObservable, Access = public )
   brand
end

Best Answer

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MATLAB: How to make a push button respond to clicking with the right mouse button

MATLAB: Implementing listener and callback, infinite loop

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