<itemvalue="{@template flutter.widgets.list_view.prototypeItem} If non-null, forces the children to have the same extent as the given widget in the scroll direction. Specifying an [prototypeItem] is more efficient than letting the children determine their own extent because the scrolling machinery can make use of the foreknowledge of the children's extent to save work, for example when the scroll position changes drastically. See also: [SliverPrototypeExtentList], the sliver used internally when this property is provided. It constrains its box children to have the same extent as a prototype item along the main axis. The [itemExtent] property, which allows forcing the children's extent to a given value. The [itemExtentBuilder] property, which allows forcing the children's extent to be the value returned by the callback. {@endtemplate}"/>
<itemvalue="A material expansion panel. It has a header and a body and can be either expanded or collapsed. The body of the panel is only visible when it is expanded. {@youtube 560 315 https:www.youtube.comwatch?v=2aJZzRMziJc} Expansion panels are only intended to be used as children for [ExpansionPanelList]."/>
<itemvalue="A material expansion panel. It has a header and a body and can be either expanded or collapsed. The body of the panel is only visible when it is expanded. {@youtube 560 315 https:www.youtube.comwatch?v=2aJZzRMziJc} Expansion panels are only intended to be used as children for [ExpansionPanelList]."/>
<itemvalue="reduced map ids"/>
<itemvalue="reduced map ids"/>
<itemvalue="初始化"/>
<itemvalue="初始化"/>
@ -60,12 +61,11 @@
<itemvalue="{@tool dartpad} This example shows how to use an [Expanded] widget in a [Column] so that its middle child, a [Container] here, expands to fill the space."/>
<itemvalue="{@tool dartpad} This example shows how to use an [Expanded] widget in a [Column] so that its middle child, a [Container] here, expands to fill the space."/>
<itemvalue="An [Expanded] widget must be a descendant of a [Row], [Column], or [Flex], and the path from the [Expanded] widget to its enclosing [Row], [Column], or [Flex] must contain only [StatelessWidget]s or [StatefulWidget]s (not other kinds of widgets, like [RenderObjectWidget]s)."/>
<itemvalue="An [Expanded] widget must be a descendant of a [Row], [Column], or [Flex], and the path from the [Expanded] widget to its enclosing [Row], [Column], or [Flex] must contain only [StatelessWidget]s or [StatefulWidget]s (not other kinds of widgets, like [RenderObjectWidget]s)."/>
<itemvalue="Using an [Expanded] widget makes a child of a [Row], [Column], or [Flex] expand to fill the available space along the main axis (e.g., horizontally for a [Row] or vertically for a [Column]). If multiple children are expanded, the available space is divided among them according to the [flex] factor."/>
<itemvalue="Using an [Expanded] widget makes a child of a [Row], [Column], or [Flex] expand to fill the available space along the main axis (e.g., horizontally for a [Row] or vertically for a [Column]). If multiple children are expanded, the available space is divided among them according to the [flex] factor."/>
<itemvalue="A widget that expands a child of a [Row], [Column], or [Flex] so that the child fills the available space."/>