collapse method
Bring the panel to PanelState.collapsed, if this is not a Two-state panel.
Returned future is completed when the panel is collapsed.
(Animates to PanelSize.collapsedHeight).
Implementation
Future<Null> collapse() async => controlling
? panel!._metadata.isTwoStatePanel
? null
: _setPanelPosition(panel!,
duration: currentState == PanelState.closed
? _durationCollapsed
: currentState == PanelState.expanded
? _durationExpanded
: _getDuration(
from: currentPosition,
to: panel!._metadata.collapsedHeight),
to: panel!._metadata.collapsedHeight)
: Future.error('Missing Controller');