title: How can I detect focus on child view inside a Tabbed Page in Xamarin.Forms?
body: <p>I have a TabbedPage, which includes 3 pages (A,B,C). I need to detect (using some override method) when a page is active/selected from tabbed control. I tried some override methods such us OnAppearing with no result, because during debugging process I noticed OnAppearing was fired when TabbedPage was firstly initialized, so when I selected for example the second page (page B) this method was not fired. Is there any optimal way to detect switching between tabs inside child view?</p>