Implement IconButton

Runtime/material/icon_button.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using Unity.UIWidgets.rendering;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.service;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.widgets;
+
+namespace Unity.UIWidgets.material {
+
+    public class IconButton : StatelessWidget {
+
+        const double _kMinButtonSize = 48.0;
+
+        public IconButton(
+            Key key = null,
+            double iconSize = 24.0,
+            EdgeInsets padding = null,
+            Alignment alignment = null,
+            Widget icon = null,
+            Color color = null,
+            Color highlightColor = null,
+            Color splashColor = null,
+            Color disabledColor = null,
+            VoidCallback onPressed = null,
+            string tooltip = null
+        ) : base(key : key) {
+            D.assert(icon != null);
+            this.iconSize = iconSize;
+            this.alignment = alignment ?? Alignment.center;
+            this.padding = padding ?? EdgeInsets.all(8.0);
+        }
+
+        public readonly double iconSize;
+
+        public readonly EdgeInsets padding;
+
+        public readonly Alignment alignment;
+
+        public readonly Widget icon;
+
+        public readonly Color color;
+
+        public readonly Color splashColor;
+
+        public readonly Color highlightColor;
+
+        public readonly Color disabledColor;
+
+        public readonly VoidCallback onPressed;
+
+        public readonly string tooltip;
+
+        public override Widget build(BuildContext context) {
+            MaterialDebug.debugCheckHasMaterial(context);
+            Color currentColor;
+            if (onPressed != null)
+                currentColor = color;
+            else
+                currentColor = disabledColor ?? Theme.of(context).disabledColor;
+
+            Widget result = new ConstrainedBox(
+                constraints: new BoxConstraints(minWidth: _kMinButtonSize, minHeight: _kMinButtonSize),
+                child: new Padding(
+                  padding: padding,
+                  child: new SizedBox(
+                    height: iconSize,
+                    width: iconSize,
+                    child: new Align(
+                      alignment: alignment,
+                      child: IconTheme.merge(
+                        data: new IconThemeData(
+                          size: iconSize,
+                          color: currentColor
+                        ),
+                        child: icon
+                      )
+                    )
+                  )
+                )
+            );
+
+            return new InkResponse(
+              onTap: (GestureTapCallback)(() => onPressed()),
+              child: result,
+              highlightColor: highlightColor ?? Theme.of(context).highlightColor,
+              splashColor: splashColor ?? Theme.of(context).splashColor,
+              radius: Math.Max(
+                Material.defaultSplashRadius,
+                (iconSize + Math.Min(padding.horizontal, padding.vertical)) * 0.7
+                // x 0.5 for diameter -> radius and + 40% overflow derived from other Material apps.
+              )
+        
+            );
+        }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<Widget>("icon", icon, showName: false));
+            properties.add(new ObjectFlagProperty<VoidCallback>("onPressed", onPressed, ifNull: "disabled"));
+            properties.add(new StringProperty("tooltip", tooltip, defaultValue: null, quoted: false));
+        }
+    }
+}