flutter_widget_class_diagram.plantuml

@startuml
skinparam monochrome true
left to right direction
scale 0.8

abstract Widget {
    :: 描述 Element 設定 ::
    ==
    + Widget({Key key})
    ..
    + Key key
    ==
    + createElement() → Element
    + debugFillProperties(\n\
    DiagnosticPropertiesBuilder properties\n\
) → void
    + toStringShort() → String
    == Static ==
    + canUpdate(\n\
    Widget oldWidget, Widget newWidget\n\
) → bool
}

abstract StatelessWidget {
    :: 無可變狀態 ::
    ==
    + StatelessWidget({Key key})
    ==
    + **build(BuildContext context) → Widget**
    + createElement() → StatelessElement
    == Implementers ==
    - AboutDialog
    - AlertDialog
    - Text
    - Theme
    - Title
    - ...
}

abstract StatefulWidget {
    :: 具有可變狀態 ::
    ==
    + StatefulWidget({Key key})
    ..
    + createElement() → StatefulElement
    + **createState() → State<StatefulWidget>**
    == Implementers ==
    - AnimatedList
    - AnimatedWidget
    - AppBar
    - CupertinoApp
    - CupertinoButton
    - ...
}

abstract ProxyWidget {
    :: 可代理一個 Widget ::
    ==
    + ProxyWidget({Key key, @required Widget child})
    ..
    + child → Widget
}

abstract InheritedWidget {
    :: 可往下傳播資訊 ::
    ==
    + InheritedWidget({Key key, Widget child})
    ==
    + createElement() → InheritedElement
    + updateShouldNotify(\n\
    covariant InheritedWidget oldWidget\n\
) → bool
    == Implementers ==
    - Actions
    - ButtonBarTheme
    - ScrollConfiguration
    - MediaQuery
    - ...
}

abstract ParentDataWidget<T extends RenderObjectWidget> {
    :: 可 hook ParentData 給下面的 RenderObjectWidget ::
    ==
    + ParentDataWidget({Key key, Widget child})
    ==
    + applyParentData(RenderObject renderObject) → void
    + createElement() → ParentDataElement<T>
    + debugCanApplyOutOfTurn() → bool
    + debugDescribeInvalidAncestorChain({\n\
    String description,\n\
    DiagnosticsNode ownershipChain,\n\
    bool foundValidAncestor,\n\
    Iterable<Widget> badAncestors\n\
}) → Iterable<DiagnosticsNode>
    + debugIsValidAncestor(RenderObjectWidget ancestor) → bool
    == Implementers ==
    - Flexible
    - KeepAlive
    - LayoutId
    - Positioned
    - TableCell
}

abstract PreferredSizeWidget {
    :: 如無限制，可指定 Widget 期望尺寸 ::
    ==
    + PreferredSizeWidget()
    --
    + preferredSize → Size
    == Implementers ==
    - AppBar
    - PreferredSize
    - TabBar
    - ...
}

abstract RenderObjectWidget {
    :: 用來設定 RenderObjectElement ::
    ==
    + RenderObjectWidget({Key key})
    ==
    + createElement() → RenderObjectElement
    + createRenderObject(BuildContext context) → RenderObject
    + didUnmountRenderObject(\n\
    covariant RenderObject renderObject\n\
) → void
    + updateRenderObject(\n\
    BuildContext context,\n\
    covariant RenderObject renderObject\n\
) → void
    == Implementers ==
    - ConstrainedLayoutBuilder
    - SingleChildRenderObjectWidget
    - SliverWithKeepAliveWidget
    - Table
    - ...
}

abstract State<T extends StatefulWidget> {
    + State()
    --
    + context → BuildContext
    + mounted → bool
    + widget → T
    ==
    + **build(BuildContext context) → Widget**
    + deactivate() → void
    + debugFillProperties(\n\
    DiagnosticPropertiesBuilder properties\n\
) → void
    + didChangeDependencies() → void
    + didUpdateWidget(covariant T oldWidget) → void
    + dispose() → void
    + **initState() → void**
    + reassemble() → void
    + **setState(VoidCallback fn) → void**
    == Implementers ==
    - AnimatedListState
    - DrawerControllerState
    ...
}

StatelessWidget --|> Widget
StatefulWidget --|> Widget
ProxyWidget --|> Widget
InheritedWidget --|> ProxyWidget
ParentDataWidget --|> ProxyWidget
PreferredSizeWidget --|> Widget
RenderObjectWidget --|> Widget
State "1" *--* "1" StatefulWidget

@enduml