Added horizontal and vertical alignment properties to Stack so that the origin of non-positioned children can be specified. Currently all of the non-positioned children just end up with their top-left at 0,0. Now, for example, you can center the children by specifying verticalAlignment: 0.5, horizontalAlignment: 0.5.
Added IndexedStack which only paints the stack child specified by the index property. Since it's a Stack, it's as big as the biggest non-positioned child. This component will be essential for building mobile drop down menus.
Added a (likely temporary) example that demonstrates IndexedStack.
Focus.at() and company should be on Focus, not FocusState.
_notifyDescendants() was using the wrong runtimeType.
Let InheritedWidget update the descendants during build.
When you setState() during build, assert that you're not
markNeedsBuild()ing someone who isn't a descendant.
Typo in Widget.toString().
(These are changes cherry-picked from in-flight branches since they are
more independent and could be helpful even without those changes.)
- Change RouteBuilder's signature to take a single argument in which the
other fields are placed, so that we can keep iterating on those
arguments without having to break compatibility each time. Also, this
makes defining route builders much simpler (only one argument to
ignore rather than a variable number).
- Expose the next performance to RouteBuilders, since sometimes the
route itself might not be where it's used.
- Allow BuildContext to be used to walk children, just like it can for
ancestors
- Allow BuildContext to be used to get the Widget of the current
BuildContext
- Allow StatefulComponentElement to be referenced with a type
specialisation so that you don't have to cast when you know what the
type you're dealing with actually is.
The ShaderMask widget enables rendering its child with an alpha channel defined by a Shader. For example if the Shader was a linear gradient in alpha then the component behind the ShaderMask's child would appear wherever the gradient's alpha value was not fully opaque.
The card_collection.dart example demonstrates this. Select the "Let the sun shine" checkbox in the app's drawer.
I'm not sure this specific incarnation of the test ever crashed, since
the original test depended on user interaction and now works fine, but
just in case, here's a regression test for it so I can close that issue.
This also slightly changes the Widget.toString() output to include the
key since that will make debugging easier.
- Rename EdgeDims constructor to EdgeDims.TRBL().
- Add operator== to Size and Offset so that you can compare Size to
DebugSize in checked mode.
- Add Size.lerp().
- Add various operators to EdgeDims. (*, /, ~/, %)
- Add EdgeDims.lerp().
- Update style guide. I went there to fix an EdgeDims constructor
example, and stayed because some recent things came up and I wanted to
add them before I forgot.
Introduce a Draggable class that wraps all the logic of dragging
something and dropping it on a DragTarget.
Update examples/widgets/drag_and_drop.dart accordingly.
Make the performance/transition part of routes optional.
Initial snap offset support for ScrollableWidgetList (and ScrollableList<T>) and ScrollableMixedWidgetList. If a ```toSnapOffset(scrollOffset)``` function is provided, fling Scrolls will coast to the returned value. If ```alignmentOffset``` is specified then fling scrolls conclude when toSnapOffset's value lines up with the Scrollable widget's origin + alignmentOffset. For example if the Scrollable widget's height was 200.0, and alignmentOffset:100.0 was specified, then fling scrolls would end with the value returned by toSnapOffset() lined up with the center of the Scrollable.
This approach to Scrollable snapping assumes that the layout of whatever the Scrollable contains is known at the outset. This is often true however a ScrollableMixedWidgetList may not know its items' sizes until they've been reached by scrolling.
This is a first cut at snapping support. Among the things that remain to be done:
- Scrolling limits trump snapping. Snapping should probably trump scrolling limits.
- Drag scrolls aren't snapped. This may be desirable so perhaps the feature should be controlled with a flag.
- Specifying alignmentOffset as a percentage would probably be more convenient.
- It would be nice if one could wrap items in a SnapOffset value like: ```new SnapOffset(0.5, child: myItem)``` to snap to the center of the item.
Updated the CardCollection example: snapping and fixed size items can be turned on/off with Drawer checkboxes.
This patch makes a number of changes:
1) buildDirtyComponents now prevents all calls to setState, not just those
higher in the tree. This change is necessary for consistency with
MixedViewport and HomogeneousViewport because those widgets already build
subwidgets with that restriction. If the "normal" build didn't enforce that
rule, then some widgets would break when put inside a mixed or homogeneous
viewport.
2) We now notify global key listeners in a microtask after beginFrame. That
means setState is legal in these callbacks and that we'll produce another
frame if someone calls setState in such a callback.
