Initial commit of Effen reactive framework experiment for Sky

sky/examples/fn/widgets/radio.dart

+part of widgets;
+
+class Radio extends ButtonBase {
+
+  Object value;
+  Object groupValue;
+  ValueChanged onChanged;
+
+  static Style _style = new Style('''
+    display: inline-block;
+    -webkit-user-select: none;
+    width: 14px;
+    height: 14px;
+    border-radius: 7px;
+    border: 1px solid blue;
+    margin: 0 5px;'''
+  );
+
+  static Style _highlightStyle = new Style('''
+    display: inline-block;
+    -webkit-user-select: none;
+    width: 14px;
+    height: 14px;
+    border-radius: 7px;
+    border: 1px solid blue;
+    margin: 0 5px;
+    background-color: orange;'''
+  );
+
+  static Style _dotStyle = new Style('''
+    -webkit-user-select: none;
+    width: 10px;
+    height: 10px;
+    border-radius: 5px;
+    background-color: black;
+    margin: 2px;'''
+  );
+
+  Radio({
+    Object key,
+    this.onChanged,
+    this.value,
+    this.groupValue
+  }) : super(key: key);
+
+  Node render() {
+    return new Container(
+      style: _highlight ? _highlightStyle : _style,
+      onClick: _handleClick,
+      onPointerDown: _handlePointerDown,
+      onPointerUp: _handlePointerUp,
+      onPointerCancel: _handlePointerCancel,
+      children: value == groupValue ?
+          [new Container( style : _dotStyle )] : null
+    );
+  }
+
+  void _handleClick(sky.Event e) {
+    onChanged(value);
+  }
+}