Implement measurement using futures

client/samples/swarm/Views.dart

 // Copyright (c) 2011, 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.
 
 // This file contains View framework classes.
 // As it grows, it may need to be split into multiple files.
 
 /** A factory that creates a view from a data model. */
 interface ViewFactory<D> {
   View newView(D item);
@@ skipping 202 matching lines @@
       scroller = new Scroller(
           _containerElem,
           _vertical /* verticalScrollEnabled */,
           !_vertical /* horizontalScrollEnabled */,
           true /* momentumEnabled */,
           () {
             num width = _layout.getWidth(_viewLength);
             num height = _layout.getHeight(_viewLength);
             width = width != null ? width : 0;
             height = height != null ? height : 0;
-            return new Size(width, height);
+            final completer = new Completer<Size>();
+            completer.complete(new Size(width, height));
+            return completer.future;
           },
           _paginate && _snapToItems ?
               Scroller.FAST_SNAP_DECELERATION_FACTOR : 1);
       scroller.onContentMoved.add((e) => renderVisibleItems(false));
       if (_pages != null) {
         watch(_pages.target, (s) => _onPageSelected());
       }
 
       if (_snapToItems) {
         scroller.onDecelStart.add((e) => _decelStart());
@@ skipping 46 matching lines @@
       style.height = '${height}px';
     }
     // TODO(jacobr): this should be specified by the default CSS for a
     // GenericListView.
     style.overflow = 'hidden';
   }
 
 
   void onResize() {
     int lastViewLength = _viewLength;
-    calculateViewLength();
-    if (_viewLength != lastViewLength) {
-      if (_scrollbar != null) {
-        _scrollbar.refresh();
+    node.rect.then((ElementRect rect) {
+      _viewLength = _vertical ? rect.offset.height : rect.offset.width;
+      if (_viewLength != lastViewLength) {
+        if (_scrollbar != null) {
+          _scrollbar.refresh();
+        }
+        renderVisibleItems(true);
       }
-      renderVisibleItems(true);
-    }
-  }
-
- void calculateViewLength() {
-    if (_vertical) {
-      _viewLength = node.offsetHeight;
-    } else {
-      _viewLength = node.offsetWidth;
-    }
+    }); 
   }
 
   void enterDocument() {
     if (scroller != null) {
       onResize();
 
       if (_scrollbar != null) {
         _scrollbar.initialize();
       }
     }
@@ skipping 665 matching lines @@
 
     container = node.query('.dialog-body');
     container.nodes.add(_content.node);
 
     return node;
   }
 
   /** Override to handle dialog done. */
   void onDone() { }
 }