Видео ютуба по тегу Staggeredgridview Is Undefined

Solving the StaggeredGridView is undefined Error in Flutter
Solving the StaggeredGridView is undefined Error in Flutter
Solving the Undefined name 'viewModel' Error in Flutter's Staggered Grid View
Solving the Undefined name 'viewModel' Error in Flutter's Staggered Grid View
StaggeredGridView is undefined
StaggeredGridView is undefined