Converted Observatory nav-refresh element

runtime/observatory/lib/src/elements/nav/refresh.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:html';
+import 'dart:async';
+import 'package:observatory/src/elements/helpers/tag.dart';
+import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
+
+class RefreshEvent {
+  final NavRefreshElement element;
+  RefreshEvent(this.element);
+}
+
+class NavRefreshElement extends HtmlElement implements Renderable {
+  static const tag = const Tag<NavRefreshElement>('nav-refresh-wrapped');
+
+  RenderingScheduler _r;
+
+  Stream<RenderedEvent<NavRefreshElement>> get onRendered => _r.onRendered;
+
+  final StreamController<RefreshEvent> _onRefresh =
+                                new StreamController<RefreshEvent>.broadcast();
+  Stream<RefreshEvent> get onRefresh => _onRefresh.stream;
+
+  bool _disabled;
+  String _label;
+  bool get disabled => _disabled;
+  String get label => _label;
+  set disabled(bool value) {
+    if (_disabled != value) {
+      _disabled = value;
+      _r.dirty();
+    } else {
+      _r.scheduleNotification();
+    }
+  }
+  set label(String value) {
+    if (_label != value) {
+      _label = value;
+      _r.dirty();
+    } else {
+      _r.scheduleNotification();
+    }
+  }
+
+
+  factory NavRefreshElement({String label: 'Refresh', bool disabled: false,
+                             RenderingQueue queue}) {
+    assert(label != null);
+    assert(disabled != null);
+    NavRefreshElement e = document.createElement(tag.name);
+    e._r = new RenderingScheduler(e, queue: queue);
+    e._label = label;
+    e._disabled = disabled;
+    return e;
+  }
+
+  NavRefreshElement.created() : super.created();
+
+  @override
+  void attached() { super.attached(); _r.enable(); }
+
+  @override
+  void detached() { super.detached(); children = []; _r.disable(notify: true); }
+
+  void render() {
+    children = [
+      new LIElement()
+        ..children = [
+          new ButtonElement()
+            ..text = label
+            ..disabled = disabled
+            ..onClick.map(_toEvent).listen(_refresh)
+        ]
+    ];
+  }
+
+  RefreshEvent _toEvent(_) {
+    return new RefreshEvent(this);
+  }
+
+  void _refresh(RefreshEvent e) {
+    if (_disabled) return;
+    _onRefresh.add(e);
+  }
+
+  void refresh() {
+    if (_disabled) return;
+    _refresh(new RefreshEvent(this));
+  }
+}