diff options
Diffstat (limited to 'Xamarin.Forms.Platform.Android/VisualElementPackager.cs')
| -rw-r--r-- | Xamarin.Forms.Platform.Android/VisualElementPackager.cs | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.Android/VisualElementPackager.cs b/Xamarin.Forms.Platform.Android/VisualElementPackager.cs new file mode 100644 index 00000000..e7e6ab6f --- /dev/null +++ b/Xamarin.Forms.Platform.Android/VisualElementPackager.cs @@ -0,0 +1,217 @@ +using System; +using System.Collections.Generic; +using System.Collections.ObjectModel; +using AView = Android.Views.View; + +namespace Xamarin.Forms.Platform.Android +{ + public class VisualElementPackager : IDisposable + { + readonly EventHandler<ElementEventArgs> _childAddedHandler; + readonly EventHandler<ElementEventArgs> _childRemovedHandler; + readonly EventHandler _childReorderedHandler; + List<IVisualElementRenderer> _childViews; + + bool _disposed; + + IVisualElementRenderer _renderer; + + public VisualElementPackager(IVisualElementRenderer renderer) + { + if (renderer == null) + throw new ArgumentNullException("renderer"); + + _childAddedHandler = OnChildAdded; + _childRemovedHandler = OnChildRemoved; + _childReorderedHandler = OnChildrenReordered; + + _renderer = renderer; + _renderer.ElementChanged += (sender, args) => SetElement(args.OldElement, args.NewElement); + } + + public void Dispose() + { + if (_disposed) + return; + _disposed = true; + + if (_renderer != null) + { + if (_childViews != null) + { + _childViews.Clear(); + _childViews = null; + } + + _renderer.Element.ChildAdded -= _childAddedHandler; + _renderer.Element.ChildRemoved -= _childRemovedHandler; + + _renderer.Element.ChildrenReordered -= _childReorderedHandler; + _renderer = null; + } + } + + public void Load() + { + SetElement(null, _renderer.Element); + } + + void AddChild(VisualElement view, IVisualElementRenderer oldRenderer = null, RendererPool pool = null, bool sameChildren = false) + { + Performance.Start(); + + if (_childViews == null) + _childViews = new List<IVisualElementRenderer>(); + + IVisualElementRenderer renderer = oldRenderer; + if (pool != null) + renderer = pool.GetFreeRenderer(view); + if (renderer == null) + { + Performance.Start("New renderer"); + renderer = Platform.CreateRenderer(view); + Performance.Stop("New renderer"); + } + + if (renderer == oldRenderer) + { + Platform.SetRenderer(renderer.Element, null); + renderer.SetElement(view); + } + + Performance.Start("Set renderer"); + Platform.SetRenderer(view, renderer); + Performance.Stop("Set renderer"); + + Performance.Start("Add view"); + if (!sameChildren) + { + _renderer.ViewGroup.AddView(renderer.ViewGroup); + _childViews.Add(renderer); + } + Performance.Stop("Add view"); + + Performance.Stop(); + } + + void EnsureChildOrder() + { + for (var i = 0; i < _renderer.Element.LogicalChildren.Count; i++) + { + Element child = _renderer.Element.LogicalChildren[i]; + var element = (VisualElement)child; + if (element != null) + { + IVisualElementRenderer r = Platform.GetRenderer(element); + _renderer.ViewGroup.BringChildToFront(r.ViewGroup); + } + } + } + + void OnChildAdded(object sender, ElementEventArgs e) + { + var view = e.Element as VisualElement; + if (view != null) + AddChild(view); + if (_renderer.Element.LogicalChildren[_renderer.Element.LogicalChildren.Count - 1] != view) + EnsureChildOrder(); + } + + void OnChildRemoved(object sender, ElementEventArgs e) + { + Performance.Start(); + var view = e.Element as VisualElement; + if (view != null) + RemoveChild(view); + + Performance.Stop(); + } + + void OnChildrenReordered(object sender, EventArgs e) + { + EnsureChildOrder(); + } + + void RemoveChild(VisualElement view) + { + IVisualElementRenderer renderer = Platform.GetRenderer(view); + _childViews.Remove(renderer); + renderer.ViewGroup.RemoveFromParent(); + renderer.Dispose(); + } + + void SetElement(VisualElement oldElement, VisualElement newElement) + { + Performance.Start(); + + var sameChildrenTypes = false; + + ReadOnlyCollection<Element> newChildren = null, oldChildren = null; + + RendererPool pool = null; + if (oldElement != null) + { + if (newElement != null) + { + sameChildrenTypes = true; + + oldChildren = oldElement.LogicalChildren; + newChildren = newElement.LogicalChildren; + if (oldChildren.Count == newChildren.Count) + { + for (var i = 0; i < oldChildren.Count; i++) + { + if (oldChildren[i].GetType() != newChildren[i].GetType()) + { + sameChildrenTypes = false; + break; + } + } + } + else + sameChildrenTypes = false; + } + + oldElement.ChildAdded -= _childAddedHandler; + oldElement.ChildRemoved -= _childRemovedHandler; + + oldElement.ChildrenReordered -= _childReorderedHandler; + + if (!sameChildrenTypes) + { + _childViews = new List<IVisualElementRenderer>(); + pool = new RendererPool(_renderer, oldElement); + pool.ClearChildrenRenderers(); + } + } + + if (newElement != null) + { + Performance.Start("Setup"); + newElement.ChildAdded += _childAddedHandler; + newElement.ChildRemoved += _childRemovedHandler; + + newElement.ChildrenReordered += _childReorderedHandler; + + newChildren = newChildren ?? newElement.LogicalChildren; + + for (var i = 0; i < newChildren.Count; i++) + { + IVisualElementRenderer oldRenderer = null; + if (oldChildren != null && sameChildrenTypes) + oldRenderer = _childViews[i]; + + AddChild((VisualElement)newChildren[i], oldRenderer, pool, sameChildrenTypes); + } + +#if DEBUG + //if (renderer.Element.LogicalChildren.Any() && renderer.ViewGroup.ChildCount != renderer.Element.LogicalChildren.Count) + // throw new InvalidOperationException ("SetElement did not create the correct number of children"); +#endif + Performance.Stop("Setup"); + } + + Performance.Stop(); + } + } +}
\ No newline at end of file |