[ScrollablePositionedList] Add support for `keyboardDismissBehavior `

[xsahil03x]

Similar to regular ScrollViews, we need this property to automatically dismiss the keyboard when the scrollable_positioned_list is dragged.

More info here: https://api.flutter.dev/flutter/widgets/ScrollViewKeyboardDismissBehavior-class.html

[mleonhard]

I'm developing a mobile app page which can display error messages informing the user that they must solve a problem. Tapping on an error message will scroll the appropriate widget into view and hi-light it so the user can use the widget to resolve the problem. The page uses a ListView with keyboardDismissBehavior: ScrollViewKeyboardDismissBehavior.onDrag. It contains text-input widgets.

Since ListView contains no way to scroll a particular widget into view, I am investigating using flutter_widgets: ScrollablePositionedList . I need ScrollablePositionedList to support keyboardDismissBehavior so I can implement this feature.

Related: Provide method and/or config to programmatically scroll to ListView index (flutter#12319)

It would be so nice if Scrollable was an interface and ListView implemented it. Then I could use Scrollable.ensureVisible.

[marcglasberg]

@jamesderlin This issue is a low hanging fruit. Can be implemented in 10 mins.

[dkbast]

Really looking forward to this!