public override void invoke(FocusNode node, Intent intent)
{
ScrollableState state = Scrollable.of(node.context);
D.assert(state != null, () => "ScrollAction was invoked on a context that has no scrollable parent");
D.assert(state.position.havePixels, () => "Scrollable must be laid out before it can be scrolled via a ScrollAction");
if (state.widget.physics != null && !state.widget.physics.shouldAcceptUserOffset(state.position))
{
return;
}
float increment = _getIncrement(state, intent as ScrollIntent);
if (increment == 0.0f)
{
return;
}
state.position.moveTo(
state.position.pixels + increment,
duration: TimeSpan.FromMilliseconds(100),
curve: Curves.easeInOut
);
}
public override bool inDirection(FocusNode currentNode, TraversalDirection direction)
{
FocusScopeNode nearestScope = currentNode.nearestScope;
FocusNode focusedChild = nearestScope.focusedChild;
if (focusedChild == null)
{
FocusNode firstFocus = findFirstFocusInDirection(currentNode, direction) ?? currentNode;
switch (direction)
{
case TraversalDirection.up:
case TraversalDirection.left:
FocusTravesalUtils._focusAndEnsureVisible(
firstFocus,
alignmentPolicy: ScrollPositionAlignmentPolicy.keepVisibleAtStart
);
break;
case TraversalDirection.right:
case TraversalDirection.down:
FocusTravesalUtils._focusAndEnsureVisible(
firstFocus,
alignmentPolicy: ScrollPositionAlignmentPolicy.keepVisibleAtEnd
);
break;
}
return(true);
}
if (_popPolicyDataIfNeeded(direction, nearestScope, focusedChild))
{
return(true);
}
FocusNode found = null;
ScrollableState focusedScrollable = Scrollable.of(focusedChild.context);
switch (direction)
{
case TraversalDirection.down:
case TraversalDirection.up:
IEnumerable <FocusNode> eligibleNodes = _sortAndFilterVertically(
direction,
focusedChild.rect,
nearestScope.traversalDescendants
);
if (focusedScrollable != null && !focusedScrollable.position.atEdge())
{
IEnumerable <FocusNode> filteredEligibleNodes = LinqUtils <FocusNode> .WhereList(eligibleNodes, ((FocusNode node) => Scrollable.of(node.context) == focusedScrollable));
if (filteredEligibleNodes.Count() != 0)
{
eligibleNodes = filteredEligibleNodes;
}
}
if (eligibleNodes.Count() == 0)
{
break;
}
List <FocusNode> sorted = eligibleNodes.ToList();
if (direction == TraversalDirection.up)
{
//sorted = sorted.reversed.toList();
sorted.Reverse();
sorted = sorted.ToList();
}
Rect band = Rect.fromLTRB(focusedChild.rect.left, float.NegativeInfinity, focusedChild.rect.right, float.PositiveInfinity);
IEnumerable <FocusNode> inBand = LinqUtils <FocusNode> .WhereList(sorted, ((FocusNode node) => !node.rect.intersect(band).isEmpty));
if (inBand.Count() != 0)
{
found = inBand.First();
break;
}
FocusTravesalUtils.mergeSort <FocusNode>(sorted, compare: (FocusNode a, FocusNode b) => {
return((a.rect.center.dx - focusedChild.rect.center.dx).abs().CompareTo((b.rect.center.dx - focusedChild.rect.center.dx).abs()));
});
found = sorted.First();
break;
case TraversalDirection.right:
case TraversalDirection.left:
eligibleNodes = _sortAndFilterHorizontally(direction, focusedChild.rect, nearestScope);
if (focusedScrollable != null && !focusedScrollable.position.atEdge())
{
IEnumerable <FocusNode> filteredEligibleNodes = LinqUtils <FocusNode> .WhereList(eligibleNodes, ((FocusNode node) => Scrollable.of(node.context) == focusedScrollable));
if (filteredEligibleNodes.Count() != 0)
{
eligibleNodes = filteredEligibleNodes;
}
}
if (eligibleNodes.Count() == 0)
{
break;
}
sorted = eligibleNodes.ToList();
if (direction == TraversalDirection.left)
{
sorted.Reverse();
sorted = sorted.ToList();
//sorted = sorted.reversed.toList();
}
band = Rect.fromLTRB(float.NegativeInfinity, focusedChild.rect.top, float.PositiveInfinity, focusedChild.rect.bottom);
inBand = LinqUtils <FocusNode> .WhereList(sorted, ((FocusNode node) => !node.rect.intersect(band).isEmpty));
if (inBand.Count() != 0)
{
found = inBand.First();
break;
}
FocusTravesalUtils.mergeSort <FocusNode>(sorted, compare: (FocusNode a, FocusNode b) => {
return((a.rect.center.dy - focusedChild.rect.center.dy).abs().CompareTo((b.rect.center.dy - focusedChild.rect.center.dy).abs()));
});
found = sorted.First();
break;
}
if (found != null)
{
_pushPolicyData(direction, nearestScope, focusedChild);
switch (direction)
{
case TraversalDirection.up:
case TraversalDirection.left:
FocusTravesalUtils._focusAndEnsureVisible(
found,
alignmentPolicy: ScrollPositionAlignmentPolicy.keepVisibleAtStart
);
break;
case TraversalDirection.down:
case TraversalDirection.right:
FocusTravesalUtils._focusAndEnsureVisible(
found,
alignmentPolicy: ScrollPositionAlignmentPolicy.keepVisibleAtEnd
);
break;
}
return(true);
}
return(false);
}
public override bool isEnabled(BuildContext context)
{
return(Scrollable.of(context) != null);
}
public bool _popPolicyDataIfNeeded(TraversalDirection direction, FocusScopeNode nearestScope, FocusNode focusedChild)
{
_DirectionalPolicyData policyData = _policyData[nearestScope];
if (policyData != null && policyData.history.isNotEmpty() && policyData.history.First().direction != direction)
{
if (policyData.history.Last().node.parent == null)
{
invalidateScopeData(nearestScope);
return(false);
}
bool popOrInvalidate(TraversalDirection _direction)
{
FocusNode lastNode = policyData.history.removeLast().node;
if (Scrollable.of(lastNode.context) != Scrollable.of(FocusManagerUtils.primaryFocus.context))
{
invalidateScopeData(nearestScope);
return(false);
}
ScrollPositionAlignmentPolicy alignmentPolicy = ScrollPositionAlignmentPolicy.explicitPolicy;
switch (_direction)
{
case TraversalDirection.up:
case TraversalDirection.left:
alignmentPolicy = ScrollPositionAlignmentPolicy.keepVisibleAtStart;
break;
case TraversalDirection.right:
case TraversalDirection.down:
alignmentPolicy = ScrollPositionAlignmentPolicy.keepVisibleAtEnd;
break;
}
FocusTravesalUtils._focusAndEnsureVisible(
lastNode,
alignmentPolicy: alignmentPolicy
);
return(true);
}
switch (direction)
{
case TraversalDirection.down:
case TraversalDirection.up:
switch (policyData.history.First().direction)
{
case TraversalDirection.left:
case TraversalDirection.right:
invalidateScopeData(nearestScope);
break;
case TraversalDirection.up:
case TraversalDirection.down:
if (popOrInvalidate(direction))
{
return(true);
}
break;
}
break;
case TraversalDirection.left:
case TraversalDirection.right:
switch (policyData.history.First().direction)
{
case TraversalDirection.left:
case TraversalDirection.right:
if (popOrInvalidate(direction))
{
return(true);
}
break;
case TraversalDirection.up:
case TraversalDirection.down:
invalidateScopeData(nearestScope);
break;
}
break;
}
}
if (policyData != null && policyData.history.isEmpty())
{
invalidateScopeData(nearestScope);
}
return(false);
}