bug fixes (meterial 3)

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

             ButtonBarThemeData barTheme = ButtonBarTheme.of(context);
 
             ButtonThemeData buttonTheme = parentButtonTheme.copyWith(
-                textTheme: buttonTextTheme ?? barTheme.buttonTextTheme ?? ButtonTextTheme.primary,
-                minWidth: buttonMinWidth ?? barTheme.buttonMinWidth ?? 64.0f,
-                height: buttonHeight ?? barTheme.buttonHeight ?? 36.0f,
-                padding: buttonPadding ?? barTheme.buttonPadding ?? EdgeInsets.symmetric(horizontal: 8.0f),
-                alignedDropdown: buttonAlignedDropdown ?? barTheme.buttonAlignedDropdown ?? false,
-                layoutBehavior: layoutBehavior ?? barTheme.layoutBehavior ?? ButtonBarLayoutBehavior.padded
+                textTheme: buttonTextTheme ?? barTheme?.buttonTextTheme ?? ButtonTextTheme.primary,
+                minWidth: buttonMinWidth ?? barTheme?.buttonMinWidth ?? 64.0f,
+                height: buttonHeight ?? barTheme?.buttonHeight ?? 36.0f,
+                padding: buttonPadding ?? barTheme?.buttonPadding ?? EdgeInsets.symmetric(horizontal: 8.0f),
+                alignedDropdown: buttonAlignedDropdown ?? barTheme?.buttonAlignedDropdown ?? false,
+                layoutBehavior: layoutBehavior ?? barTheme?.layoutBehavior ?? ButtonBarLayoutBehavior.padded
             );
 
             float paddingUnit = buttonTheme.padding.horizontal / 4.0f;
-                    mainAxisAlignment: alignment ?? barTheme.alignment ?? MainAxisAlignment.end,
-                    mainAxisSize: mainAxisSize ?? barTheme.mainAxisSize ?? MainAxisSize.max,
-                    overflowDirection: overflowDirection ?? barTheme.overflowDirection ?? VerticalDirection.down,
+                    mainAxisAlignment: alignment ?? barTheme?.alignment ?? MainAxisAlignment.end,
+                    mainAxisSize: mainAxisSize ?? barTheme?.mainAxisSize ?? MainAxisSize.max,
+                    overflowDirection: overflowDirection ?? barTheme?.overflowDirection ?? VerticalDirection.down,
                     children: children.Select((Widget childWidget) => {
                         return (Widget) new Padding(
                             padding: EdgeInsets.symmetric(horizontal: paddingUnit),

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

             float? indent = null,
             float? endIndent = null,
             Color color = null) : base(key: key) {
-            D.assert(height >= 0.0);
+            D.assert(height == null || height >= 0.0);
+            D.assert(thickness == null || thickness >= 0.0);
+            D.assert(indent == null || indent >= 0.0);
+            D.assert(endIndent == null || endIndent >= 0.0);
             this.height = height;
             this.thickness = thickness;
             this.indent = indent;
                     child: new Container(
                         height: thickness,
                         //TODO: update to EdgeInsetsGeometry
-                        margin: (EdgeInsets) (EdgeInsetsGeometry) EdgeInsetsDirectional.only(start: indent,
-                            end: endIndent),
+                        /*margin: EdgeInsetsDirectional.only(start: indent,
+                            end: endIndent),*/
                         decoration: new BoxDecoration(
                             border: new Border(
                                 bottom: createBorderSide(context, color: color, width: thickness))

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

             this.height = height;
             this.enableFeedback = enableFeedback;
             this.child = child;
+            this.autofocus = autofocus;
         }
 
         public readonly VoidCallback onPressed;

com.unity.uiwidgets/Runtime/services/text_input.cs

             TextRange composing = null) {
             
             D.assert(text != null);
-            D.assert(selection != null);
             this.text = text;
             this.composing = composing ?? TextRange.empty;
 

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

                 "minLines and maxLines must be null when expands is true."
             );
             D.assert(!obscureText || maxLines == 1, () => "Obscured fields cannot be multiline.");
+            
+            scrollPadding = scrollPadding ?? EdgeInsets.all(20.0f);
             D.assert(scrollPadding != null);
             toolbarOptions = toolbarOptions ?? new ToolbarOptions(
                 copy: true,
             this.showCursor = !readOnly;
             this.keyboardType = keyboardType ?? (maxLines == 1 ? TextInputType.text : TextInputType.multiline);
             this.locale = locale;
-            this.scrollPadding = scrollPadding ?? EdgeInsets.all(20.0f);
+            this.scrollPadding = scrollPadding;
             this.controller = controller;
             this.focusNode = focusNode;
             this.obscureText = obscureText;
             if (widget.controller.selection != oldWidget.controller.selection) {
                 _selectionOverlay?.update(_value);
             }
-            _selectionOverlay.handlesVisible = widget.showSelectionHandles;
+
+            if (_selectionOverlay != null) {
+                _selectionOverlay.handlesVisible = widget.showSelectionHandles;
+            }
+
             if (widget.focusNode != oldWidget.focusNode) {
                 oldWidget.focusNode.removeListener(_handleFocusChanged);
                 _focusAttachment?.detach();
                         fontFamily: style.fontFamily,
                         fontSize: style.fontSize,
                         fontWeight: style.fontWeight,
-                        textDirection: (TextDirection)_textDirection,
+                        textDirection: _textDirection.Value,
                         textAlign: widget.textAlign
                     );
                 }

Samples/UIWidgetsSamples_2019_4/Assets/MaterialSample/BottomAppBarSample.cs

+using System.Collections.Generic;
+using uiwidgets;
+using Unity.UIWidgets.engine2;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.material;
+using Unity.UIWidgets.rendering;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.widgets;
+using UnityEngine;
+using Color = Unity.UIWidgets.ui.Color;
+using ui_ = Unity.UIWidgets.widgets.ui_;
+
+namespace UIWidgetsSample {
+    
+    public class BottomAppBarSample : UIWidgetsPanel {
+
+        protected override void main() {
+            ui_.runApp(new MaterialApp(
+                showPerformanceOverlay: false,
+                home: new BottomAppBarWidget()));
+        }
+
+        protected new void OnEnable() {
+            base.OnEnable();
+        }
+    }
+    
+    public class BottomAppBarWidget : StatelessWidget {
+        public BottomAppBarWidget(Key key = null) : base(key) {
+
+        }
+
+        public override Widget build(BuildContext context) {
+            return new Scaffold(
+                backgroundColor: Colors.grey,
+                bottomNavigationBar: new BottomAppBar(
+                    child: new Row(
+                        mainAxisSize: MainAxisSize.max,
+                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                        children: new List<Widget> {
+                            new IconButton(icon: new Icon(Unity.UIWidgets.material.Icons.menu), onPressed: () => { }),
+                            new IconButton(icon: new Icon(Unity.UIWidgets.material.Icons.account_balance),
+                                onPressed: () => { })
+                        })));
+        }
+    }
+}

Samples/UIWidgetsSamples_2019_4/Assets/MaterialSample/BottomAppBarSample.cs.meta

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