<itemvalue="A sliver that contains a single box widget. Slivers are special-purpose widgets that can be combined using a [CustomScrollView] to create custom scroll effects. A [SliverToBoxAdapter] is a basic sliver that creates a bridge back to one of the usual box-based widgets. Rather than using multiple [SliverToBoxAdapter] widgets to display multiple box widgets in a [CustomScrollView], consider using [SliverList], [SliverFixedExtentList], [SliverPrototypeExtentList], or [SliverGrid], which are more efficient because they instantiate only those children that are actually visible through the scroll view's viewport."/>
<itemvalue="A material design app bar that integrates with a [CustomScrollView]. An app bar consists of a toolbar and potentially other widgets, such as a [TabBar] and a [FlexibleSpaceBar]. App bars typically expose one or more common actions with [IconButton]s which are optionally followed by a [PopupMenuButton] for less common operations. {@youtube 560 315 https:www.youtube.comwatch?v=R9C5KMJKluE} Sliver app bars are typically used as the first child of a [CustomScrollView], which lets the app bar integrate with the scroll view so that it can vary in height according to the scroll offset or float above the other content in the scroll view. For a fixed-height app bar at the top of the screen see [AppBar], which is used in the [Scaffold.appBar] slot. The AppBar displays the toolbar widgets, [leading], [title], and [actions], above the [bottom] (if any). If a [flexibleSpace] widget is specified then it is stacked behind the toolbar and the bottom widget."/>
<itemvalue="A sliver that places multiple box children in a two dimensional arrangement. [SliverGrid] places its children in arbitrary positions determined by [gridDelegate]. Each child is forced to have the size specified by the [gridDelegate]. The main axis direction of a grid is the direction in which it scrolls; the cross axis direction is the orthogonal direction. {@youtube 560 315 https:www.youtube.comwatch?v=ORiTTaVY6mM} {@tool snippet} This example, which would be inserted into a [CustomScrollView.slivers] list, shows twenty boxes in a pretty teal grid:"/>
<itemvalue="A sliver that places multiple box children in a linear array along the main axis. Each child is forced to have the [SliverConstraints.crossAxisExtent] in the cross axis but determines its own main axis extent. [SliverList] determines its scroll offset by "dead reckoning" because children outside the visible part of the sliver are not materialized, which means [SliverList] cannot learn their main axis extent. Instead, newly materialized children are placed adjacent to existing children. {@youtube 560 315 https:www.youtube.comwatch?v=ORiTTaVY6mM} If the children have a fixed extent in the main axis, consider using [SliverFixedExtentList] rather than [SliverList] because [SliverFixedExtentList] does not need to perform layout on its children to obtain their extent in the main axis and is therefore more efficient. {@macro flutter.widgets.SliverChildDelegate.lifecycle} See also: <https:flutter.devdocsdevelopmentuiadvancedslivers>, a description of what slivers are and how to use them. [SliverFixedExtentList], which is more efficient for children with the same extent in the main axis. [SliverPrototypeExtentList], which is similar to [SliverFixedExtentList] except that it uses a prototype list item instead of a pixel value to define the main axis extent of each item. [SliverGrid], which places its children in arbitrary positions."/>
<itemvalue="A [ScrollView] that creates custom scroll effects using slivers. A [CustomScrollView] lets you supply [slivers] directly to create various scrolling effects, such as lists, grids, and expanding headers. For example, to create a scroll view that contains an expanding app bar followed by a list and a grid, use a list of three slivers: [SliverAppBar], [SliverList], and [SliverGrid]. [Widget]s in these [slivers] must produce [RenderSliver] objects. To control the initial scroll offset of the scroll view, provide a [controller] with its [ScrollController.initialScrollOffset] property set. {@animation 400 376 https:flutter.github.ioassets-for-api-docsassetswidgetscustom_scroll_view.mp4} {@tool snippet} This sample code shows a scroll view that contains a flexible pinned app bar, a grid, and an infinite list."/>
<itemvalue="A base class for the `State` of widgets with implicit animations. [ImplicitlyAnimatedWidgetState] requires that subclasses respond to the animation themselves. If you would like `setState()` to be called automatically as the animation changes, use [AnimatedWidgetBaseState]. Properties that subclasses choose to animate are represented by [Tween] instances. Subclasses must implement the [forEachTween] method to allow [ImplicitlyAnimatedWidgetState] to iterate through the widget's fields and animate them."/>
<itemvalue="Animated version of [Align] which automatically transitions the child's position over a given duration whenever the given [alignment] changes. Here's an illustration of what this can look like, using a [curve] of [Curves.fastOutSlowIn]. {@animation 250 266 https:flutter.github.ioassets-for-api-docsassetswidgetsanimated_align.mp4} For the animation, you can choose a [curve] as well as a [duration] and the widget will automatically animate to the new target [alignment]. If you require more control over the animation (e.g. if you want to stop it mid-animation), consider using an [AlignTransition] instead, which takes a provided [Animation] as argument. While that allows you to fine-tune the animation, it also requires more development overhead as you have to manually manage the lifecycle of the underlying [AnimationController]. {@tool dartpad} The following code implements the [AnimatedAlign] widget, using a [curve] of [Curves.fastOutSlowIn]. See code in examplesapilibwidgetsimplicit_animationsanimated_align.0.dart {@end-tool} See also: [AnimatedContainer], which can transition more values at once. [AnimatedPadding], which can animate the padding instead of the alignment. [AnimatedSlide], which can animate the translation of child by a given offset relative to its size. [AnimatedPositioned], which, as a child of a [Stack], automatically transitions its child's position over a given duration whenever the given position changes."/>
<itemvalue="stage 2 and 3 done."/>
@ -51,16 +56,11 @@
<itemvalue="Notify the framework that the internal state of this object has changed. Whenever you change the internal state of a [State] object, make the change in a function that you pass to [setState]: ```dart setState(() { _myState = newValue; }); ``` The provided callback is immediately called synchronously. It must not return a future (the callback cannot be `async`), since then it would be unclear when the state was actually being set. Calling [setState] notifies the framework that the internal state of this object has changed in a way that might impact the user interface in this subtree, which causes the framework to schedule a [build] for this [State] object. If you just change the state directly without calling [setState], the framework might not schedule a [build] and the user interface for this subtree might not be updated to reflect the new state. Generally it is recommended that the `setState` method only be used to wrap the actual changes to the state, not any computation that might be associated with the change. For example, here a value used by the [build] function is incremented, and then the change is written to disk, but only the increment is wrapped in the `setState`: ```dart Future<void> _incrementCounter() async { setState(() { _counter++; }); Directory directory = await getApplicationDocumentsDirectory(); final String dirName = directory.path; await File('dircounter.txt').writeAsString('_counter'); } ``` It is an error to call this method after the framework calls [dispose]. You can determine whether it is legal to call this method by checking whether the [mounted] property is true."/>
<itemvalue="Makes this Rx looks like a function so you can update a new value using `rx(someOtherValue)`. Practical to assign the Rx directly to some Widget that has a signature ::onChange( value ) Example: ``` final myText = 'GetX rocks!'.obs; in your Constructor, just to check it works :P ever( myText, print ) ; in your build(BuildContext) { TextField( onChanged: myText, ),"/>
<itemvalue="updates the value to `null` and adds it to the Stream. Even with null-safety coming, is still an important feature to support, as `call()` doesn't accept `null` values. For instance, `InputDecoration.errorText` has to be null to not show the "error state". Sample: ``` final inputError = ''.obs..nil(); print('{inputError.runtimeType}: inputError'); outputs > RxString: null ``` void nil() { subject.add(_value = null); }"/>
<itemvalue="Cause the record did not support by hive cache, remove this value by now Comment reply to record, null by default, soulsRecord or usersRecord. if reply to type is soul, this value is soul record if reply to type is user, this value is user record dynamic replyToRecord;"/>
<itemvalue="折叠"/>
<itemvalue="update last unsenddeleted message preview for on chat list page."/>
<itemvalue="update last message preview for unsenddeleted message on chat list page."/>
<itemvalue="update last message preview on chat list page for unsenddeleted message."/>
debuggerx
3 years ago