Merge pull request #281 from UnityTech/yczhang1.5.4

[Cupertino] Implement nav bar (with ValueListenerBuilder and DefaultTextStyleTransition)

Runtime/cupertino/page_scaffold.cs

                     ? existingMediaQuery.viewInsets.copyWith(bottom: 0.0f)
                     : existingMediaQuery.viewInsets;
 
-                bool fullObstruction =
+                bool? fullObstruction =
-                if (fullObstruction) {
+                if (fullObstruction == true) {
                     paddedContent = new MediaQuery(
                         data: existingMediaQuery
                             .removePadding(removeTop: true)
     }
 
     public abstract class ObstructingPreferredSizeWidget : PreferredSizeWidget {
-        public bool fullObstruction { get; }
+
+        protected ObstructingPreferredSizeWidget(Key key = null) : base(key: key) {}
+        public virtual bool? fullObstruction { get; }
     }
 }

Runtime/cupertino/text_theme.cs

 
         readonly TextStyle _navTitleTextStyle;
 
-        TextStyle navTitleTextStyle {
+        public TextStyle navTitleTextStyle {
             get {
                 return this._navTitleTextStyle ??
                        (this._isLight

Runtime/cupertino/theme.cs

         }
 
         public CupertinoThemeData copyWith(
-            Brightness? brightness,
-            Color primaryColor,
-            Color primaryContrastingColor,
-            CupertinoTextThemeData textTheme,
-            Color barBackgroundColor,
-            Color scaffoldBackgroundColor
+            Brightness? brightness = null,
+            Color primaryColor = null,
+            Color primaryContrastingColor = null,
+            CupertinoTextThemeData textTheme = null,
+            Color barBackgroundColor = null,
+            Color scaffoldBackgroundColor = null
         ) {
             return new CupertinoThemeData(
                 brightness: brightness ?? this._brightness,

Runtime/widgets/transitions.cs

 using Unity.UIWidgets.ui;
 using UnityEngine;
 using Rect = Unity.UIWidgets.ui.Rect;
+using TextStyle = Unity.UIWidgets.painting.TextStyle;
 
 namespace Unity.UIWidgets.widgets {
     public abstract class AnimatedWidget : StatefulWidget {
                 alignment: this.alignment.value,
                 widthFactor: this.widthFactor,
                 heightFactor: this.heightFactor,
+                child: this.child
+            );
+        }
+    }
+
+    public class DefaultTextStyleTransition : AnimatedWidget {
+        public DefaultTextStyleTransition(
+            Key key = null,
+            Animation<TextStyle> style = null,
+            Widget child = null,
+            TextAlign? textAlign = null,
+            bool softWrap = true,
+            TextOverflow overflow = TextOverflow.clip,
+            int? maxLines = null
+        ) : base(key: key, listenable: style) {
+            D.assert(style != null);
+            D.assert(child != null);
+            this.textAlign = textAlign;
+            this.softWrap = softWrap;
+            this.overflow = overflow;
+            this.maxLines = maxLines;
+            this.child = child;
+        }
+
+        Animation<TextStyle> style {
+            get { return (Animation<TextStyle>) this.listenable; }
+        }
+
+        public readonly TextAlign? textAlign;
+
+        public readonly bool softWrap;
+        public readonly TextOverflow overflow;
+        public readonly int? maxLines;
+        public readonly Widget child;
+
+        protected internal override Widget build(BuildContext context) {
+            return new DefaultTextStyle(
+                style: this.style.value,
+                textAlign: this.textAlign,
+                softWrap: this.softWrap,
+                overflow: this.overflow,
+                maxLines: this.maxLines,
                 child: this.child
             );
         }

Runtime/cupertino/bottom_app_bar.cs

+using System.Collections.Generic;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.rendering;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.widgets;
+using TextStyle = Unity.UIWidgets.painting.TextStyle;
+
+namespace Unity.UIWidgets.cupertino {
+    class BottomAppBarUtils {
+        public const float _kTabBarHeight = 50.0f;
+        public static readonly Color _kDefaultTabBarBorderColor = new Color(0x4C000000);
+    }
+
+
+    public class CupertinoTabBar : StatelessWidget {
+        public CupertinoTabBar(
+            Key key = null,
+            List<BottomNavigationBarItem> items = null,
+            ValueChanged<int> onTap = null,
+            int currentIndex = 0,
+            Color backgroundColor = null,
+            Color activeColor = null,
+            Color inactiveColor = null,
+            float iconSize = 30.0f,
+            Border border = null
+        ) : base(key: key) {
+            D.assert(items != null);
+            D.assert(items.Count >= 2,
+                () => "Tabs need at least 2 items to conform to Apple's HIG"
+            );
+            D.assert(0 <= currentIndex && currentIndex < items.Count);
+            D.assert(inactiveColor != null);
+            this.items = items;
+            this.onTap = onTap;
+            this.currentIndex = currentIndex;
+
+            this.backgroundColor = backgroundColor;
+            this.activeColor = activeColor;
+            this.inactiveColor = inactiveColor ?? CupertinoColors.inactiveGray;
+            this.iconSize = iconSize;
+            this.border = border ?? new Border(
+                              top: new BorderSide(
+                                  color: BottomAppBarUtils._kDefaultTabBarBorderColor,
+                                  width: 0.0f, // One physical pixel.
+                                  style: BorderStyle.solid
+                              )
+                          );
+        }
+
+        public readonly List<BottomNavigationBarItem> items;
+
+        public readonly ValueChanged<int> onTap;
+
+        public readonly int currentIndex;
+
+        public readonly Color backgroundColor;
+
+        public readonly Color activeColor;
+
+        public readonly Color inactiveColor;
+
+        public readonly float iconSize;
+
+        public readonly Border border;
+
+        public Size preferredSize {
+            get { return Size.fromHeight(BottomAppBarUtils._kTabBarHeight); }
+        }
+
+        bool opaque(BuildContext context) {
+            Color backgroundColor =
+                this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor;
+            return backgroundColor.alpha == 0xFF;
+        }
+
+        public override Widget build(BuildContext context) {
+            float bottomPadding = MediaQuery.of(context).padding.bottom;
+
+            Widget result = new DecoratedBox(
+                decoration: new BoxDecoration(
+                    border: this.border,
+                    color: this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor
+                ),
+                child: new SizedBox(
+                    height: BottomAppBarUtils._kTabBarHeight + bottomPadding,
+                    child: IconTheme.merge( // Default with the inactive state.
+                        data: new IconThemeData(
+                            color: this.inactiveColor,
+                            size: this.iconSize
+                        ),
+                        child: new DefaultTextStyle( // Default with the inactive state.
+                            style: CupertinoTheme.of(context).textTheme.tabLabelTextStyle
+                                .copyWith(color: this.inactiveColor),
+                            child: new Padding(
+                                padding: EdgeInsets.only(bottom: bottomPadding),
+                                child: new Row(
+                                    crossAxisAlignment: CrossAxisAlignment.end,
+                                    children: this._buildTabItems(context)
+                                )
+                            )
+                        )
+                    )
+                )
+            );
+
+            if (!this.opaque(context)) {
+                result = new ClipRect(
+                    child: new BackdropFilter(
+                        filter: ImageFilter.blur(sigmaX: 10.0f, sigmaY: 10.0f),
+                        child: result
+                    )
+                );
+            }
+
+            return result;
+        }
+
+        List<Widget> _buildTabItems(BuildContext context) {
+            List<Widget> result = new List<Widget> { };
+
+            for (int index = 0; index < this.items.Count; index += 1) {
+                bool active = index == this.currentIndex;
+                result.Add(
+                    this._wrapActiveItem(
+                        context,
+                        new Expanded(
+                            child: new GestureDetector(
+                                behavior: HitTestBehavior.opaque,
+                                onTap: this.onTap == null ? null : (GestureTapCallback) (() => { this.onTap(index); }),
+                                child: new Padding(
+                                    padding: EdgeInsets.only(bottom: 4.0f),
+                                    child: new Column(
+                                        mainAxisAlignment: MainAxisAlignment.end,
+                                        children: this._buildSingleTabItem(this.items[index], active)
+                                    )
+                                )
+                            )
+                        ),
+                        active: active
+                    )
+                );
+            }
+
+            return result;
+        }
+
+        List<Widget> _buildSingleTabItem(BottomNavigationBarItem item, bool active) {
+            List<Widget> components = new List<Widget> {
+                new Expanded(
+                    child: new Center(child: active ? item.activeIcon : item.icon)
+                )
+            };
+
+            if (item.title != null) {
+                components.Add(item.title);
+            }
+
+            return components;
+        }
+
+        Widget _wrapActiveItem(BuildContext context, Widget item, bool active) {
+            if (!active) {
+                return item;
+            }
+
+            Color activeColor = this.activeColor ?? CupertinoTheme.of(context).primaryColor;
+            return IconTheme.merge(
+                data: new IconThemeData(color: activeColor),
+                child: DefaultTextStyle.merge(
+                    style: new TextStyle(color: activeColor),
+                    child: item
+                )
+            );
+        }
+
+        CupertinoTabBar copyWith(
+            Key key = null,
+            List<BottomNavigationBarItem> items = null,
+            Color backgroundColor = null,
+            Color activeColor = null,
+            Color inactiveColor = null,
+            float? iconSize = null,
+            Border border = null,
+            int? currentIndex = null,
+            ValueChanged<int> onTap = null
+        ) {
+            return new CupertinoTabBar(
+                key: key ?? this.key,
+                items: items ?? this.items,
+                backgroundColor: backgroundColor ?? this.backgroundColor,
+                activeColor: activeColor ?? this.activeColor,
+                inactiveColor: inactiveColor ?? this.inactiveColor,
+                iconSize: iconSize ?? this.iconSize,
+                border: border ?? this.border,
+                currentIndex: currentIndex ?? this.currentIndex,
+                onTap: onTap ?? this.onTap
+            );
+        }
+    }
+}

Runtime/cupertino/bottom_app_bar.cs.meta

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Runtime/cupertino/nav_bar.cs.meta

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Runtime/widgets/value_listenable_builder.cs

+using Unity.UIWidgets.foundation;
+
+namespace Unity.UIWidgets.widgets {
+    public delegate Widget ValueWidgetBuilder<T>(BuildContext context, T value, Widget child);
+
+    public class ValueListenableBuilder<T> : StatefulWidget {
+        public ValueListenableBuilder(
+            ValueListenable<T> valueListenable,
+            ValueWidgetBuilder<T> builder,
+            Widget child = null
+        ) {
+            D.assert(valueListenable != null);
+            D.assert(builder != null);
+            this.valueListenable = valueListenable;
+            this.builder = builder;
+            this.child = child;
+        }
+
+        public readonly ValueListenable<T> valueListenable;
+
+        public readonly ValueWidgetBuilder<T> builder;
+
+        public readonly Widget child;
+
+        public override State createState() {
+            return new _ValueListenableBuilderState<T>();
+        }
+    }
+
+    class _ValueListenableBuilderState<T> : State<ValueListenableBuilder<T>> {
+        T value;
+
+        public override void initState() {
+            base.initState();
+            this.value = this.widget.valueListenable.value;
+            this.widget.valueListenable.addListener(this._valueChanged);
+        }
+
+        public override void didUpdateWidget(StatefulWidget _oldWidget) {
+            ValueListenableBuilder<T> oldWidget = _oldWidget as ValueListenableBuilder<T>;
+            if (oldWidget.valueListenable != this.widget.valueListenable) {
+                oldWidget.valueListenable.removeListener(this._valueChanged);
+                this.value = this.widget.valueListenable.value;
+                this.widget.valueListenable.addListener(this._valueChanged);
+            }
+
+            base.didUpdateWidget(oldWidget);
+        }
+
+        public override void dispose() {
+            this.widget.valueListenable.removeListener(this._valueChanged);
+            base.dispose();
+        }
+
+        void _valueChanged() {
+            this.setState(() => { this.value = this.widget.valueListenable.value; });
+        }
+
+        public override Widget build(BuildContext context) {
+            return this.widget.builder(context, this.value, this.widget.child);
+        }
+    }
+}

Runtime/widgets/value_listenable_builder.cs.meta

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