The first child in the GrowthDirection.forward growth direction.
Children after center will be placed in the AxisDirection determined by scrollDirection and reverse relative to the center. Children before center will be placed in the opposite of the axis direction relative to the center. This makes the center the inflection point of the growth direction.
The center must be the key of one of the slivers built by buildSlivers.
Of the built-in subclasses of ScrollView, only CustomScrollView supports center; for that class, the given key must be the key of one of the slivers in the CustomScrollView.slivers list.
Most scroll views by default are ordered GrowthDirection.forward. Changing the default values of ScrollView.anchor, ScrollView.center, or both, can configure a scroll view for GrowthDirection.reverse.
To create a local project with this code sample, run:
flutter create --sample=widgets.ScrollView.center.1 mysample
final Key? center;