ElNullElement class

空 Element 实例，通常用于初始化 Element 数组

Inheritance
Available extensions

Properties

brightness → Brightness

Available on BuildContext, provided by the FlutterContextExt extension

获取当平台亮度模式
no setter
buildScope → BuildScope
A BuildScope whose dirty Elements can only be rebuilt by BuildOwner.buildScope calls whose context argument is an Element within this BuildScope.
no setterinherited
currentBgColor → Color

Available on BuildContext, provided by the FlutterContextExt extension

访问当前背景颜色
no setter
currentTextColor → Color

Available on BuildContext, provided by the FlutterContextExt extension

访问当前文本样式
no setter
debugDoingBuild → bool
Whether the widget is currently updating the widget or render tree.
no setteroverride
debugIsActive → bool
Returns true if the Element is active.
no setterinherited
debugIsDefunct → bool
Returns true if the Element is defunct.
no setterinherited
depth → int
An integer that is guaranteed to be greater than the parent's, if any. The element at the root of the tree must have a depth greater than 0.
no setterinherited
dirty → bool
Returns true if the element has been marked as needing rebuilding.
no setterinherited
elIconTheme → IconThemeData

Available on BuildContext, provided by the ElIconThemeExt extension

全局图标主题
no setter
elTextTheme → ElTextThemeData

Available on BuildContext, provided by the ElTextThemeExt extension

全局文本主题
no setter
hashCode → int
The hash code for this object.
no setterinherited
hasHover → bool

Available on BuildContext, provided by the FlutterContextExt extension

是否激活了 hover 悬停状态
no setter
hasTap → bool

Available on BuildContext, provided by the FlutterContextExt extension

是否激活了 tap 点击状态
no setter
isDark → bool

Available on BuildContext, provided by the FlutterContextExt extension

当前环境是否是暗黑模式
no setter
ltr → bool

Available on BuildContext, provided by the FlutterContextExt extension

文本方向是否是从左到右
no setter
mounted → bool
Whether the Widget this context is associated with is currently mounted in the widget tree.
no setterinherited
owner → BuildOwner?
The object that manages the lifecycle of this element.
no setterinherited
renderObject → RenderObject?
The render object at (or below) this location in the tree.
no setterinherited
renderObjectAttachingChild → Element?
Returns the child of this Element that will insert a RenderObject into an ancestor of this Element to construct the render tree.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
size → Size?
The size of the RenderBox returned by findRenderObject.
no setterinherited
slot → Object?
Information set by parent to define where this child fits in its parent's child list.
no setterinherited
widget → Widget
The configuration for this element.
no setterinherited

Methods

activate() → void
Transition from the "inactive" to the "active" lifecycle state.
inherited
attachNotificationTree() → void
Called in Element.mount and Element.activate to register this element in the notification tree.
inherited
attachRenderObject(Object? newSlot) → void
Add renderObject to the render tree at the location specified by newSlot.
inherited
deactivate() → void
Transition from the "active" to the "inactive" lifecycle state.
inherited
deactivateChild(Element child) → void
Move the given element to the list of inactive elements and detach its render object from the render tree.
inherited
debugDeactivated() → void
Called, in debug mode, after children have been deactivated (see deactivate).
inherited
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugExpectsRenderObjectForSlot(Object? slot) → bool
Whether the child in the provided slot (or one of its descendants) must insert a RenderObject into its ancestor RenderObjectElement by calling RenderObjectElement.insertRenderObjectChild on it.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
debugGetCreatorChain(int limit) → String
Returns a description of what caused this element to be created.
inherited
debugGetDiagnosticChain() → List<Element>
Returns the parent chain from this element back to the root of the tree.
inherited
debugVisitOnstageChildren(ElementVisitor visitor) → void
Calls the argument for each child considered onstage.
inherited
dependOnInheritedElement(InheritedElement ancestor, {Object? aspect}) → InheritedWidget
Registers this build context with ancestor such that when ancestor's widget changes this build context is rebuilt.
inherited
dependOnInheritedWidgetOfExactType<T extends InheritedWidget>({Object? aspect}) → T?
Returns the nearest widget of the given type T and creates a dependency on it, or null if no appropriate widget is found.
inherited
describeElement(String name, {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.errorProperty}) → DiagnosticsNode
Returns a description of the Element associated with the current build context.
inherited
describeMissingAncestor({required Type expectedAncestorType}) → List<DiagnosticsNode>
Adds a description of a specific type of widget missing from the current build context's ancestry tree.
inherited
describeOwnershipChain(String name) → DiagnosticsNode
Adds a description of the ownership chain from a specific Element to the error report.
inherited
describeWidget(String name, {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.errorProperty}) → DiagnosticsNode
Returns a description of the Widget associated with the current build context.
inherited
detachRenderObject() → void
Remove renderObject from the render tree.
inherited
didChangeDependencies() → void
Called when a dependency of this element changes.
inherited
dispatchNotification(Notification notification) → void
Start bubbling this notification at the given build context.
inherited
doesDependOnInheritedElement(InheritedElement ancestor) → bool
Returns true if dependOnInheritedElement was previously called with ancestor.
inherited
elDuration([Duration? duration]) → Duration

Available on BuildContext, provided by the ElSyncThemeDurationExt extension

Element UI 只提供普通全局主题对象，不提供动画版本的全局主题，例如 AnimatedTheme， 创建 lerp 动画曲线相当繁琐，你可以查看官方为此写了多少代码 ThemeData.lerp。
findAncestorRenderObjectOfType<T extends RenderObject>() → T?
Returns the RenderObject object of the nearest ancestor RenderObjectWidget widget that is an instance of the given type T.
inherited
findAncestorStateOfType<T extends State<StatefulWidget>>() → T?
Returns the State object of the nearest ancestor StatefulWidget widget that is an instance of the given type T.
inherited
findAncestorWidgetOfExactType<T extends Widget>() → T?
Returns the nearest ancestor widget of the given type T, which must be the type of a concrete Widget subclass.
inherited
findDescendantStateOfType<T extends State<StatefulWidget>>([BuildContext? context]) → T?

Available on BuildContext, provided by the FlutterContextExt extension

访问指定类型 State 的后代元素，注意：对于拥有多个子项的 Widget，它只会访问第一条数据并进行递归， 所以在调用此方法前你应当确保直属后代存在目标元素
findRenderObject() → RenderObject?
The current RenderObject for the widget. If the widget is a RenderObjectWidget, this is the render object that the widget created for itself. Otherwise, it is the render object of the first descendant RenderObjectWidget.
inherited
findRootAncestorStateOfType<T extends State<StatefulWidget>>() → T?
Returns the State object of the furthest ancestor StatefulWidget widget that is an instance of the given type T.
inherited
forgetChild(Element child) → void
Remove the given child from the element's child list, in preparation for the child being reused elsewhere in the element tree.
inherited
getAncestorElement<T extends Widget>() → Element?

Available on BuildContext, provided by the FlutterContextExt extension

通过当前 context，获取最近的目标祖先 Element
getAncestorWidget<T extends Widget>() → T?

Available on BuildContext, provided by the FlutterContextExt extension

通过当前 context，获取最近的目标祖先 Widget
getElementForInheritedWidgetOfExactType<T extends InheritedWidget>() → InheritedElement?
Obtains the element corresponding to the nearest widget of the given type T, which must be the type of a concrete InheritedWidget subclass.
inherited
getInheritedWidgetOfExactType<T extends InheritedWidget>() → T?
Returns the nearest widget of the given InheritedWidget subclass T or null if an appropriate ancestor is not found.
inherited
getPosition([BuildContext? context]) → Offset

Available on BuildContext, provided by the FlutterContextExt extension

从当前 context 获取元素的坐标位置，你还可以传递另一个 Widget 的 context 作为参数，计算相对坐标
getRect([BuildContext? context]) → Rect

Available on BuildContext, provided by the FlutterContextExt extension

从当前 context 获取元素的坐标 + 宽高，你还可以传递另一个 Widget 的 context 作为参数，计算相对坐标
hasAncestorWidget<T extends Widget>() → bool

Available on BuildContext, provided by the FlutterContextExt extension

通过当前 context，检查祖先是否存在某个 Widget
inflateWidget(Widget newWidget, Object? newSlot) → Element
Create an element for the given widget and add it as a child of this element in the given slot.
inherited
markNeedsBuild() → void
Marks the element as dirty and adds it to the global list of widgets to rebuild in the next frame.
inherited
mount(Element? parent, Object? newSlot) → void
Add this element to the tree in the given slot of the given parent.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
performRebuild() → void
Cause the widget to update itself.
inherited
read<T>() → T

Available on BuildContext, provided by the ReadContext extension

Obtain a value from the nearest ancestor provider of type T.
reassemble() → void
Called whenever the application is reassembled during debugging, for example during hot reload.
inherited
rebuild({bool force = false}) → void
Cause the widget to update itself. In debug builds, also verify various invariants.
inherited
select<T, R>(R selector(T value)) → R

Available on BuildContext, provided by the SelectContext extension

Watch a value of type T exposed from a provider, and mark this widget for rebuild on changes of that value.
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String
A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String
Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a one-line detailed description of the object.
inherited
toStringShort() → String
A short, textual description of this element.
inherited
unmount() → void
Transition from the "inactive" to the "defunct" lifecycle state.
inherited
update(covariant Widget newWidget) → void
Change the widget used to configure this element.
inherited
updateChild(Element? child, Widget? newWidget, Object? newSlot) → Element?
Update the given child with the given new configuration.
inherited
updateChildren(List<Element> oldChildren, List<Widget> newWidgets, {Set<Element>? forgottenChildren, List<Object?>? slots}) → List<Element>
Updates the children of this element to use new widgets.
inherited
updateSlot(Object? newSlot) → void
Called by updateSlotForChild when the framework needs to change the slot that this Element occupies in its ancestor.
inherited
updateSlotForChild(Element child, Object? newSlot) → void
Change the slot that the given child occupies in its parent.
inherited
visitAncestorElements(ConditionalElementVisitor visitor) → void
Walks the ancestor chain, starting with the parent of this build context's widget, invoking the argument for each ancestor.
inherited
visitChildElements(ElementVisitor visitor) → void
Wrapper around visitChildren for BuildContext.
inherited
visitChildren(ElementVisitor visitor) → void
Calls the argument for each child. Must be overridden by subclasses that support having children.
inherited
watch<T>() → T

Available on BuildContext, provided by the WatchContext extension

Obtain a value from the nearest ancestor provider of type T or T?, and subscribe to the provider.

Operators

operator ==(Object other) → bool
Compare two widgets for equality.
inherited

Static Properties

instance → ElNullElement
final