showModalTopSheet<T> function

Future<T?> showModalTopSheet<T>({ required BuildContext context, required WidgetBuilder builder, Color? backgroundColor, String? barrierLabel, double? elevation, ShapeBorder? shape, Clip? clipBehavior, BoxConstraints? constraints, Color? barrierColor, bool isScrollControlled = false, double scrollControlDisabledMaxHeightRatio = _defaultScrollControlDisabledMaxHeightRatio, bool useRootNavigator = false, bool isDismissible = true, bool enableDrag = true, bool? showDragHandle, bool useSafeArea = true, RouteSettings? routeSettings, AnimationController? transitionAnimationController, Offset? anchorPoint, })

显示模态 Material Design 顶部工作表。

A DisplayFeature can split the screen into sub-screens. The closest one to anchorPoint is used to render the content.

If no anchorPoint is provided, then Directionality is used:

• for TextDirection.ltr, anchorPoint is Offset.zero, which will cause the content to appear in the top-left sub-screen.
• for TextDirection.rtl, anchorPoint is Offset(double.maxFinite, 0), which will cause the content to appear in the top-right sub-screen.

If no anchorPoint is provided, and there is no Directionality ancestor widget in the tree, then the widget asserts during build in debug mode.

'context' 参数用于查找顶部工作表的 Navigator 和 Theme。它仅在调用该方法时使用。 在顶部工作表关闭之前，可以安全地从树上移除其相应的小部件。

“useRootNavigator”参数确保根导航器在设置为“true”时用于显示 TopSheet。 当一个模态 TopSheet 需要显示在所有其他内容之上，但调用方位于另一个 Navigator 中时，这很有用。

返回一个“Future”，该解析为在关闭模态顶部工作表时传递给 Navigator.pop 的值（如果有）。

“barrierLabel”参数可用于设置自定义 barrierLabel。如果未设置，则默认为 context的 modalBarrierDismissLabel。

另请参阅：

• TopSheet, 它成为作为“builder”参数传递给 showModalTopSheet 的函数返回的小部件的父级。
• DraggableScrollableSheet, 创建一个底部工作表，该工作表会增长，然后在达到最大尺寸后变得可滚动。
• DisplayFeatureSubScreen, 它记录了 DisplayFeature 如何将屏幕拆分为子屏幕的细节。
• Material 2 规范位于 m2.material.io/components/sheets-bottom.
• Material 3 规范位于 m3.material.io/components/bottom-sheets/overview.

Implementation

Future<T?> showModalTopSheet<T>({
  required BuildContext context,
  required WidgetBuilder builder,
  Color? backgroundColor,
  String? barrierLabel,
  double? elevation,
  ShapeBorder? shape,
  Clip? clipBehavior,
  BoxConstraints? constraints,
  Color? barrierColor,
  bool isScrollControlled = false,
  double scrollControlDisabledMaxHeightRatio =
      _defaultScrollControlDisabledMaxHeightRatio,
  bool useRootNavigator = false,
  bool isDismissible = true,
  bool enableDrag = true,
  bool? showDragHandle,
  bool useSafeArea = true,
  RouteSettings? routeSettings,
  AnimationController? transitionAnimationController,
  Offset? anchorPoint,
}) {
  assert(debugCheckHasMediaQuery(context));
  assert(debugCheckHasMaterialLocalizations(context));

  final NavigatorState navigator =
      Navigator.of(context, rootNavigator: useRootNavigator);
  final MaterialLocalizations localizations = MaterialLocalizations.of(context);
  return navigator.push(
    ModalTopSheetRoute<T>(
      builder: builder,
      capturedThemes:
          InheritedTheme.capture(from: context, to: navigator.context),
      isScrollControlled: isScrollControlled,
      scrollControlDisabledMaxHeightRatio: scrollControlDisabledMaxHeightRatio,
      barrierLabel: barrierLabel ?? localizations.scrimLabel,
      barrierOnTapHint:
          localizations.scrimOnTapHint(localizations.bottomSheetLabel),
      backgroundColor: backgroundColor,
      elevation: elevation,
      shape: shape,
      clipBehavior: clipBehavior,
      constraints: constraints,
      isDismissible: isDismissible,
      modalBarrierColor: barrierColor ??
          TopSheetTheme.of(context).data?.modalBarrierColor ??
          Theme.of(context).bottomSheetTheme.modalBarrierColor,
      enableDrag: enableDrag,
      showDragHandle: showDragHandle,
      settings: routeSettings,
      transitionAnimationController: transitionAnimationController,
      anchorPoint: anchorPoint,
      useSafeArea: useSafeArea,
    ),
  );
}