MATLAB: What’s the callback function for “selecting” a TAB

app designercallbackMATLABsizecahngefcntab

Using App Designer with Tab-Group and Tabs. Now want to create and access to the call back function when the Tab is selected. With the right mouse button or help, it has "SizeChangedFcn".
How to make callback function for "selecting" thr Tab?
Also, it gives: [ 'SizeChangedFcn' callback will not execute while 'AutoResizeChildren' is set to 'on' ], even AutoResizeChildren are all set to 'OFF'.
What can stop these warnings?
Thank you for your help.

Best Answer

Hi John,
In order to set a call back to for Tab changes we require "TabGroupSelectionChanged" callback function from "TabGroup" instead of an individual "Tab".
This is how you can attach the callback in App Designer :
This callback will trigger when you have switched to a new tab, e.g., by clicking on the tab.
You may use the "app.TabGroup.SelectedTab" property to either get or set the currently selected tab. The following example shows how to do this.
>> selectedTab = app.TabGroup.SelectedTab;
>> app.TabGroup.SelectedTab = app.TabA;
This example shows how to detect that the user has switched to "TabA". 
function TabGroupSelectionChanged(app, event)
     if app.TabGroup.SelectedTab.Title == app.TabA.Title
          %Code here runs when TabA is selected
     end
end
Please refer to the "App Designer TabGroup Properties" documentation:https://www.mathworks.com/help/releases/R2019a/matlab/ref/matlab.ui.container.tabgroupappd-properties.html
Regarding your second query on warning "'SizeChangedFcn' callback will not execute while 'AutoResizeChildren' is set to 'on'", you can refere to the following MATLAB Answers:
https://www.mathworks.com/matlabcentral/answers/356343-autoresizechildren-app-designer-warning
It will give you a good understanding for why you are getting this warning.
I hope this helps.
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