phase3: nullfix field-formal field-nullable handler. 907 -> 872

lib/widgets/general/sliding_up_panel.dart

@@ -30,7 +30,7 @@ class SlidingUpPanel extends StatefulWidget {
   /// otherwise, [collapsed] will be displayed overtop
   /// of this Widget. If [panel] and [panelBuilder] are both non-null,
   /// [panel] will be used.
-  final Widget panel;
+  final Widget? panel;
 
   /// WARNING: This feature is still in beta and is subject to change without
   /// notice. Stability is not gauranteed. Provides a [ScrollController] and
@@ -38,28 +38,28 @@ class SlidingUpPanel extends StatefulWidget {
   /// the panel position with the scroll position. Useful for implementing an
   /// infinite scroll behavior. If [panel] and [panelBuilder] are both non-null,
   /// [panel] will be used.
-  final Widget Function(ScrollController sc) panelBuilder;
+  final Widget Function(ScrollController sc)? panelBuilder;
 
   /// The Widget displayed overtop the [panel] when collapsed.
   /// This fades out as the panel is opened.
-  final Widget collapsed;
+  final Widget? collapsed;
 
   /// The Widget that lies underneath the sliding panel.
   /// This Widget automatically sizes itself
   /// to fill the screen.
-  final Widget body;
+  final Widget? body;
 
   /// Optional persistent widget that floats above the [panel] and attaches
   /// to the top of the [panel]. Content at the top of the panel will be covered
   /// by this widget. Add padding to the bottom of the `panel` to
   /// avoid coverage.
-  final Widget header;
+  final Widget? header;
 
   /// Optional persistent widget that floats above the [panel] and
   /// attaches to the bottom of the [panel]. Content at the bottom of the panel
   /// will be covered by this widget. Add padding to the bottom of the `panel`
   /// to avoid coverage.
-  final Widget footer;
+  final Widget? footer;
 
   /// The height of the sliding panel when fully collapsed.
   final double minHeight;
@@ -72,13 +72,13 @@ class SlidingUpPanel extends StatefulWidget {
   /// and go directly to the open/close position. This value is represented as a
   /// percentage of the total animation distance ([maxHeight] - [minHeight]),
   /// so it must be between 0.0 and 1.0, exclusive.
-  final double snapPoint;
+  final double? snapPoint;
 
   /// A border to draw around the sliding panel sheet.
-  final Border border;
+  final Border? border;
 
   /// If non-null, the corners of the sliding panel sheet are rounded by this [BorderRadiusGeometry].
-  final BorderRadiusGeometry borderRadius;
+  final BorderRadiusGeometry? borderRadius;
 
   /// A list of shadows cast behind the sliding panel sheet.
   final List<BoxShadow> boxShadow;
@@ -87,10 +87,10 @@ class SlidingUpPanel extends StatefulWidget {
   final Color color;
 
   /// The amount to inset the children of the sliding panel sheet.
-  final EdgeInsetsGeometry padding;
+  final EdgeInsetsGeometry? padding;
 
   /// Empty space surrounding the sliding panel sheet.
-  final EdgeInsetsGeometry margin;
+  final EdgeInsetsGeometry? margin;
 
   /// Set to false to not to render the sheet the [panel] sits upon.
   /// This means that only the [body], [collapsed], and the [panel]
@@ -104,7 +104,7 @@ class SlidingUpPanel extends StatefulWidget {
   final bool panelSnapping;
 
   /// If non-null, this can be used to control the state of the panel.
-  final PanelController controller;
+  final PanelController? controller;
 
   /// If non-null, shows a darkening shadow over the [body] as the panel slides open.
   final bool backdropEnabled;
@@ -125,15 +125,15 @@ class SlidingUpPanel extends StatefulWidget {
   /// is called as the panel slides around with the
   /// current position of the panel. The position is a double
   /// between 0.0 and 1.0 where 0.0 is fully collapsed and 1.0 is fully open.
-  final void Function(double position) onPanelSlide;
+  final void Function(double position)? onPanelSlide;
 
   /// If non-null, this callback is called when the
   /// panel is fully opened
-  final VoidCallback onPanelOpened;
+  final VoidCallback? onPanelOpened;
 
   /// If non-null, this callback is called when the panel
   /// is fully collapsed.
-  final VoidCallback onPanelClosed;
+  final VoidCallback? onPanelClosed;
 
   /// If non-null and true, the SlidingUpPanel exhibits a
   /// parallax effect as the panel slides up. Essentially,
@@ -320,8 +320,8 @@ class _SlidingUpPanelState extends State<SlidingUpPanel> with SingleTickerProvid
                   top: widget.slideDirection == SlideDirection.UP ? 0.0 : null,
                   bottom: widget.slideDirection == SlideDirection.DOWN ? 0.0 : null,
                   width:  MediaQuery.of(context).size.width -
-                      (widget.margin != null ? widget.margin.horizontal : 0) -
-                      (widget.padding != null ? widget.padding.horizontal : 0),
+                      (widget.margin != null ? widget.margin!.horizontal : 0) -
+                      (widget.padding != null ? widget.padding!.horizontal : 0),
                   child: Container(
                     height: widget.maxHeight,
                     child: widget.panel != null
@@ -349,8 +349,8 @@ class _SlidingUpPanelState extends State<SlidingUpPanel> with SingleTickerProvid
                   top: widget.slideDirection == SlideDirection.UP ? 0.0 : null,
                   bottom: widget.slideDirection == SlideDirection.DOWN ? 0.0 : null,
                   width:  MediaQuery.of(context).size.width -
-                      (widget.margin != null ? widget.margin.horizontal : 0) -
-                      (widget.padding != null ? widget.padding.horizontal : 0),
+                      (widget.margin != null ? widget.margin!.horizontal : 0) -
+                      (widget.padding != null ? widget.padding!.horizontal : 0),
                   child: Container(
                     height: widget.minHeight,
                     child: widget.collapsed == null ? Container() : FadeTransition(