function playSong(object,~,varargin)
get(get(rbutton,'SelectedObject'),'String') % This is where I am getting the error
if strcmp(object.UserData,'Original')
Firstly, don't mung on the callback function argument list; it is defined to be (app,event), not something of your own making.
app is the placeholder for the global application data struct that contains all the pieces of the app plus is where you put whatever other variables you need to access across the application.
Without the rest of the user code to see the whole thing, there's not enough to fix what is wrong here, but you're going at it in a wrong manner; look at the example apps to see how callback functions are written and variables accessed within them.
the get() call is problematic; if there is more than one object of a given type that are children of a single object handle, then get() will return an array of them. If the handle is an array of objects then it will return an array of struct of the same size as h.
Even if it did work as constructed, without a variable on the LH side of an assignment, any return values will simply be displayed on the screen in the command window; not returned for your function to use.
We would need a minimal working example to be able to ferret out all the issues here...
