///  * [DisplayFeatureSubScreen], which documents the specifics of how
///    [DisplayFeature]s can split the screen into sub-screens.
///  * [showDialog], which displays a Material-style dialog.
///  * [showCupertinoDialog], which displays an iOS-style dialog.
Future<T?> showGeneralDialog<T extends Object?>({
  required BuildContext context,
  required RoutePageBuilder pageBuilder,
  bool barrierDismissible = false,
  String? barrierLabel,
  Color barrierColor = const Color(0x80000000),
  Duration transitionDuration = const Duration(milliseconds: 200),
  RouteTransitionsBuilder? transitionBuilder,
  bool useRootNavigator = true,
  RouteSettings? routeSettings,
  Offset? anchorPoint,
}) {
  assert(!barrierDismissible || barrierLabel != null);
  return Navigator.of(context, rootNavigator: useRootNavigator).push<T>(RawDialogRoute<T>(
    pageBuilder: pageBuilder,
    barrierDismissible: barrierDismissible,
    barrierLabel: barrierLabel,
    barrierColor: barrierColor,
    transitionDuration: transitionDuration,
    transitionBuilder: transitionBuilder,
    settings: routeSettings,
    anchorPoint: anchorPoint,
  ));
}

實(shí)現(xiàn)很簡單，直接調(diào)用Navigator的push方法打開了一個(gè)新的對話框路由RawDialogRoute，然后返回了push的返回值?？梢妼υ捒?qū)嶋H上正是通過路由的形式實(shí)現(xiàn)的，這也是為什么我們可以使用Navigator的pop 方法來退出對話框的原因。關(guān)于對話框的樣式定制在RawDialogRoute中，沒有什么新的東西，讀者可以自行查看。這里我只取一部分

class RawDialogRoute<T> extends PopupRoute<T> {
  /// A general dialog route which allows for customization of the dialog popup.
  RawDialogRoute({
    required RoutePageBuilder pageBuilder,
    bool barrierDismissible = true,
    Color? barrierColor = const Color(0x80000000),
    String? barrierLabel,
    Duration transitionDuration = const Duration(milliseconds: 200),
    RouteTransitionsBuilder? transitionBuilder,
    super.settings,
    this.anchorPoint,
    super.traversalEdgeBehavior,
  }) : _pageBuilder = pageBuilder,
       _barrierDismissible = barrierDismissible,
       _barrierLabel = barrierLabel,
       _barrierColor = barrierColor,
       _transitionDuration = transitionDuration,
       _transitionBuilder = transitionBuilder;

    ---....此處省略----
}