Convert Dismissable to use the ScrollStart, ScrollUpdate, and ScrollEnd gestures. Support for fling gestures is TBD.
Included a basic unit test that checks that one item can be dismissed with a press-drag-release gesture.
Fixed the scroll gesture recognizer: if the last pointer goes up and candidate recognizers still exist, then reject the gesture.
This patch makes ParentDataNode less general purpose and instead teaches Flex
and Stack how to program the parent data for their children. We used to have
this general system because parent data used to carry CSS styling, but we don't
need it anymore.
Fixes#957
Adds a HomogeneousViewport class that works like MixedViewport but
handles only children that have all the same height.
Converts ScrollableWidgetList to use that, so that we don't waste a
frame looking at the size of the contents each time we change size.
This allows a number of seemingly pointless double-pumps in the tests
to be removed.
Other changes that were necessary to support the above:
- RenderBlock now supports minExtent (think 'min-height' in CSS)
- RenderBlock now supports itemExtent (forces the height of each
child to be the same, so that the itemExtent passed to the fixed-
height scrollables are all authoritative instead of a source of
bugs when they don't match)
- RenderBlockViewport now supports horizontal scrolling
- improved the style of the isInfinite assert in box.dart
- fixed the position of a comment in mixed_viewport.dart
- added a test
- made the logic for how many items to show be more precise
If there are no other gestures in the arena, we should kick off the scroll
gesture right away. This change pulled a refactoring of how we dispatch events
to Widgets. Now we dispatch events to Widgets interleaved with their associated
RenderObjects. (Previously we dispatched to all of the RenderObjects first.)
We need to always remove the widget when you sync a non-visible
widget, even if we already have it, because otherwise we'll try to
sync it with null again later, which causes a crash.
Test in #938.
...and not when we mount and dismount.
Turns out that when we dismount, it's too late -- we've already set
renderObject to null.
We also mark the mixed viewport as dirty when it is removed from its parent.
Without this, we try to reuse the child nodes in subsequent syncs, which is a disaster.
