AlertDialog
A modal box that asks a question and waits for the answer.
Dialog
The modal surface on its own, with any content in it.
SimpleDialog
A modal list of choices, answered by picking one.
AboutDialog, AboutListTile & LicensePage
The "about this app" box, and the page listing the licences it ships.
SnackBar & ScaffoldMessenger
A short message at the bottom of the screen that goes away by itself.
BottomSheet
A modal panel sliding up from the bottom, for contextual actions.
DraggableScrollableSheet
A panel along the bottom that follows the finger between resting heights.
MaterialBanner
A message across the top of the content that stays until it is answered.
Alert
A message box in the flow of the page: info, success, warning or error.
LinearProgressIndicator & CircularProgressIndicator
How far along some work is, or that it is under way.
Skeleton
A pulsing placeholder in the shape of content that is still loading.
Tooltip
A short label that appears while the pointer rests on a widget.