Merge pull request #191 from UnityTech/yczhang

Implement nested scroll view.

Runtime/rendering/sliver_fill.cs

 
     public class RenderSliverFillRemaining : RenderSliverSingleBoxAdapter {
         public RenderSliverFillRemaining(
-            RenderBox child
+            RenderBox child = null
         ) : base(child: child) {
         }
 

Runtime/widgets/scroll_activity.cs

             }
         }
 
-        protected bool applyMoveTo(float value) {
+        protected virtual bool applyMoveTo(float value) {
             return this.del.setPixels(value) == 0.0;
         }
 

Runtime/widgets/scroll_position.cs

             ScrollContext context = null,
             bool keepScrollOffset = true,
             ScrollPosition oldPosition = null,
-            string debugLabel = null
+            string debugLabel = null,
+            object coordinator = null
         ) {
             D.assert(physics != null);
             D.assert(context != null);
             this.context = context;
             this.keepScrollOffset = keepScrollOffset;
             this.debugLabel = debugLabel;
+            this._coordinator = coordinator;
 
             if (oldPosition != null) {
                 this.absorb(oldPosition);
         public readonly bool keepScrollOffset;
 
         public readonly string debugLabel;
+
+        internal readonly object _coordinator;
 
         public float minScrollExtent {
             get { return this._minScrollExtent.Value; }

Runtime/widgets/scroll_view.cs

 
         protected abstract List<Widget> buildSlivers(BuildContext context);
 
-        protected Widget buildViewport(
+        protected virtual Widget buildViewport(
             BuildContext context,
             ViewportOffset offset,
             AxisDirection axisDirection,

Runtime/widgets/sliver.cs

         }
     }
 
+    class SliverFillRemaining : SingleChildRenderObjectWidget {
+        public SliverFillRemaining(
+            Key key = null,
+            Widget child = null
+        ) : base(key: key, child: child) {
+        }
+
+        public override RenderObject createRenderObject(BuildContext context) {
+            return new RenderSliverFillRemaining();
+        }
+    }
+
     public class KeepAlive : ParentDataWidget<SliverMultiBoxAdaptorWidget> {
         public KeepAlive(
             Key key = null,

Runtime/painting/paint_utilities.cs

+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.ui;
+using UnityEngine;
+using Canvas = Unity.UIWidgets.ui.Canvas;
+
+namespace Unity.UIWidgets.painting {
+    public static class PaintingUtilities {
+        public static void paintZigZag(Canvas canvas, Paint paint, Offset start, Offset end, int zigs, float width) {
+            D.assert(MathUtils.isFinite(zigs));
+            D.assert(zigs > 0);
+            canvas.save();
+            canvas.translate(start.dx, start.dy);
+            end = end - start;
+            canvas.rotate(Mathf.Atan2(end.dy, end.dx));
+            float length = end.distance;
+            float spacing = length / (zigs * 2.0f);
+            Path path = new Path();
+            path.moveTo(0.0f, 0.0f);
+            for (int index = 0; index < zigs; index += 1) {
+                float x = (index * 2.0f + 1.0f) * spacing;
+                float y = width * ((index % 2.0f) * 2.0f - 1.0f);
+                path.lineTo(x, y);
+            }
+
+            path.lineTo(length, 0.0f);
+            canvas.drawPath(path, paint);
+            canvas.restore();
+        }
+    }
+}

Runtime/painting/paint_utilities.cs.meta

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Runtime/widgets/nested_scroll_view.cs.meta

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