Flutter Create a notched bottomBar

please share link where you create and explain the bottom bar while coding it.

Hello sir, I learning your code but I am show a error in bottom_bar.dart files

I buy your course in udamy I download your source files but still it was earror show.

body: _pages[_selectedIndex]['page']
This line and it's title line

رائع جداااااااااااااااااااا ..من فضلك استمر