material fixes (6)

com.unity.uiwidgets/Runtime/material/banner.cs

             MaterialBannerThemeData bannerTheme = MaterialBannerTheme.of(context);
 
             bool isSingleRow = actions.Count == 1 && !forceActionsBelow;
-            EdgeInsetsGeometry padding = this.padding ?? bannerTheme.padding ?? (isSingleRow
+            EdgeInsetsGeometry padding = this.padding ?? bannerTheme?.padding ?? (isSingleRow
-                                                ?? bannerTheme.padding
+                                                ?? bannerTheme?.padding
                                                 ?? EdgeInsetsDirectional.only(end: 16.0f);
 
             Widget buttonBar = new ButtonBar(
 
             Color backgroundColor = this.backgroundColor
-                                    ?? bannerTheme.backgroundColor
+                                    ?? bannerTheme?.backgroundColor
-                                  ?? bannerTheme.contentTextStyle
+                                  ?? bannerTheme?.contentTextStyle
                                   ?? theme.textTheme.bodyText2;
 
             var rowList = new List<Widget>();

com.unity.uiwidgets/Runtime/material/bottom_app_bar.cs

 
         public override Widget build(BuildContext context) {
             BottomAppBarTheme babTheme = BottomAppBarTheme.of(context);
-            NotchedShape notchedShape = widget.shape ?? babTheme.shape;
+            NotchedShape notchedShape = widget.shape ?? babTheme?.shape;
             CustomClipper<Path> clipper = notchedShape != null
                 ? (CustomClipper<Path>) new _BottomAppBarClipper(
                     geometry: geometryListenable,
                 : new ShapeBorderClipper(shape: new RoundedRectangleBorder());
             
-            float elevation = widget.elevation ?? babTheme.elevation ?? _defaultElevation;
-            Color color = widget.color ?? babTheme.color ?? Theme.of(context).bottomAppBarColor;
+            float elevation = widget.elevation ?? babTheme?.elevation ?? _defaultElevation;
+            Color color = widget.color ?? babTheme?.color ?? Theme.of(context).bottomAppBarColor;
             Color effectiveColor = ElevationOverlay.applyOverlay(context, color, elevation);
             return new PhysicalShape(
                 clipper: clipper,

com.unity.uiwidgets/Runtime/material/bottom_sheet.cs

 
         public override Widget build(BuildContext context) {
             BottomSheetThemeData bottomSheetTheme = Theme.of(context).bottomSheetTheme;
-            Color color = widget.backgroundColor ?? bottomSheetTheme.backgroundColor;
-            float elevation = widget.elevation ?? bottomSheetTheme.elevation ?? 0;
-            ShapeBorder shape = widget.shape ?? bottomSheetTheme.shape;
-            Clip clipBehavior = widget.clipBehavior ?? bottomSheetTheme.clipBehavior ?? Clip.none;
+            Color color = widget.backgroundColor ?? bottomSheetTheme?.backgroundColor;
+            float elevation = widget.elevation ?? bottomSheetTheme?.elevation ?? 0;
+            ShapeBorder shape = widget.shape ?? bottomSheetTheme?.shape;
+            Clip clipBehavior = widget.clipBehavior ?? bottomSheetTheme?.clipBehavior ?? Clip.none;
 
             Widget bottomSheet = new Material(
                 key: _childKey,

com.unity.uiwidgets/Runtime/material/divider.cs

         public static BorderSide createBorderSide(BuildContext context, Color color = null, float? width = null) {
             Color effectiveColor = color
                                    ?? (context != null
-                                       ? (DividerTheme.of(context).color ?? Theme.of(context).dividerColor)
+                                       ? (DividerTheme.of(context)?.color ?? Theme.of(context).dividerColor)
-                                   ?? (context != null ? DividerTheme.of(context).thickness : null)
+                                   ?? (context != null ? DividerTheme.of(context)?.thickness : null)
                                    ?? 0.0f;
 
             // Prevent assertion since it is possible that context is null and no color
 
         public override Widget build(BuildContext context) {
             DividerThemeData dividerTheme = DividerTheme.of(context);
-            float height = this.height ?? dividerTheme.space ?? 16.0f;
-            float thickness = this.thickness ?? dividerTheme.thickness ?? 0.0f;
-            float indent = this.indent ?? dividerTheme.indent ?? 0.0f;
-            float endIndent = this.endIndent ?? dividerTheme.endIndent ?? 0.0f;
+            float height = this.height ?? dividerTheme?.space ?? 16.0f;
+            float thickness = this.thickness ?? dividerTheme?.thickness ?? 0.0f;
+            float indent = this.indent ?? dividerTheme?.indent ?? 0.0f;
+            float endIndent = this.endIndent ?? dividerTheme?.endIndent ?? 0.0f;
 
             return new SizedBox(
                 height: height,

com.unity.uiwidgets/Runtime/material/ink_well.cs

             }
 
             D.assert(_currentSplash == null);
-            foreach (_HighlightType highlight in _highlights.Keys) {
+            foreach (_HighlightType highlight in _highlights.Keys.ToList()) {
                 _highlights[highlight]?.dispose();
                 _highlights[highlight] = null;
             }

com.unity.uiwidgets/Runtime/material/tooltip.cs

               );
             }
 
-            height = widget.height ?? tooltipTheme.height ?? _defaultTooltipHeight;
-            padding = widget.padding ?? tooltipTheme.padding ?? _defaultPadding;
-            margin = widget.margin ?? tooltipTheme.margin ?? _defaultMargin;
-            verticalOffset = widget.verticalOffset ?? tooltipTheme.verticalOffset ?? _defaultVerticalOffset;
-            preferBelow = widget.preferBelow ?? tooltipTheme.preferBelow ?? _defaultPreferBelow;
-            excludeFromSemantics = widget.excludeFromSemantics ?? tooltipTheme.excludeFromSemantics ?? _defaultExcludeFromSemantics;
-            decoration = widget.decoration ?? tooltipTheme.decoration ?? defaultDecoration;
-            textStyle = widget.textStyle ?? tooltipTheme.textStyle ?? defaultTextStyle;
-            waitDuration = widget.waitDuration ?? tooltipTheme.waitDuration ?? _defaultWaitDuration;
-            showDuration = widget.showDuration ?? tooltipTheme.showDuration ?? _defaultShowDuration;
+            height = widget.height ?? tooltipTheme?.height ?? _defaultTooltipHeight;
+            padding = widget.padding ?? tooltipTheme?.padding ?? _defaultPadding;
+            margin = widget.margin ?? tooltipTheme?.margin ?? _defaultMargin;
+            verticalOffset = widget.verticalOffset ?? tooltipTheme?.verticalOffset ?? _defaultVerticalOffset;
+            preferBelow = widget.preferBelow ?? tooltipTheme?.preferBelow ?? _defaultPreferBelow;
+            excludeFromSemantics = widget.excludeFromSemantics ?? tooltipTheme?.excludeFromSemantics ?? _defaultExcludeFromSemantics;
+            decoration = widget.decoration ?? tooltipTheme?.decoration ?? defaultDecoration;
+            textStyle = widget.textStyle ?? tooltipTheme?.textStyle ?? defaultTextStyle;
+            waitDuration = widget.waitDuration ?? tooltipTheme?.waitDuration ?? _defaultWaitDuration;
+            showDuration = widget.showDuration ?? tooltipTheme?.showDuration ?? _defaultShowDuration;
 
             Widget result = new GestureDetector(
               behavior: HitTestBehavior.opaque,

com.unity.uiwidgets/Runtime/widgets/framework.cs

         }
     }
 
-    public class ParentDataElement<T> : ParentDataElement where T : ParentData {
+    public class ParentDataElement<T> : ParentDataElement where T : IParentData {
         public ParentDataElement(ParentDataWidget<T> widget) : base(widget)
         {
         }
                     ((RenderObjectElement) child)._updateParentData(widget);
                 }
                 else {
-                    D.assert(!(child is ParentDataElement<ParentData>));
+                    D.assert(!(child is ParentDataElement<IParentData>));
                     child.visitChildren(applyParentDataToChild);
                 }
             };