element_tree_child_locator

Description:

element tree child locator

Traverses the element tree downward, looking for elements/widgets that meet certain criteria.
Use Like:
List<Element> matches = context.findChildElementsMatching( ( e ) => e.widget is MyCustomWidget );
Element firstMatch = context.findFirstChildElementForWidgetOfType<MyCustomWidget>();
Element lastMatch = context.findLastChildElementForWidgetOfType<MyCustomWidget>();
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Additional information #
USE WITH CAUTION!!
Calling this method is potentially expensive for build contexts that
correspond to RenderObjectWidgets (O(N) in the number of children).
Calling this method recursively is extremely expensive (O(N) in the number
of descendants), and should be avoided if possible. Generally it is
significantly cheaper to use an InheritedWidget and have the descendants
pull data down, than it is to use visitChildElements recursively to push
data down to them.
Depth Condition / Conflict #
When traversing the element tree downward, there can often times be the same
type of element at the same depth.
I plan on adding DepthConflictStrategy support in the future to provide some
further instruction on what to do if there is a conflict.
Example (future) Cases:
DepthConflictStrategy.useFirst;
DepthConflictStrategy.useLast;
DepthConflictStrategy.custom;
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