Track tap gestures

Ooui.Forms/EventTracker.cs

@@ -0,0 +1,169 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.Linq;
+using Xamarin.Forms;
+
+using NativeView = Ooui.Element;
+
+namespace Ooui.Forms
+{
+    public class EventTracker
+    {
+        readonly NotifyCollectionChangedEventHandler _collectionChangedHandler;
+
+        readonly Dictionary<IGestureRecognizer, NativeGestureRecognizer> _gestureRecognizers = new Dictionary<IGestureRecognizer, NativeGestureRecognizer> ();
+
+        readonly IVisualElementRenderer _renderer;
+        bool _disposed;
+        NativeView _handler;
+
+        public EventTracker (IVisualElementRenderer renderer)
+        {
+            if (renderer == null)
+                throw new ArgumentNullException (nameof (renderer));
+
+            _collectionChangedHandler = ModelGestureRecognizersOnCollectionChanged;
+
+            _renderer = renderer;
+            _renderer.ElementChanged += OnElementChanged;
+        }
+
+        ObservableCollection<IGestureRecognizer> ElementGestureRecognizers {
+            get {
+                if (_renderer?.Element is View)
+                    return ((View)_renderer.Element).GestureRecognizers as ObservableCollection<IGestureRecognizer>;
+                return null;
+            }
+        }
+
+        public void Dispose ()
+        {
+            if (_disposed)
+                return;
+
+            _disposed = true;
+
+            foreach (var kvp in _gestureRecognizers) {
+                RemoveGestureRecognizer (_handler, kvp.Value);
+                kvp.Value.Dispose ();
+            }
+
+            _gestureRecognizers.Clear ();
+
+            if (ElementGestureRecognizers != null)
+                ElementGestureRecognizers.CollectionChanged -= _collectionChangedHandler;
+
+            _handler = null;
+        }
+
+        void ModelGestureRecognizersOnCollectionChanged (object sender, NotifyCollectionChangedEventArgs notifyCollectionChangedEventArgs)
+        {
+            LoadRecognizers ();
+        }
+
+        void OnElementChanged (object sender, VisualElementChangedEventArgs e)
+        {
+            if (e.OldElement != null) {
+                // unhook
+                var oldView = e.OldElement as View;
+                if (oldView != null) {
+                    var oldRecognizers = (ObservableCollection<IGestureRecognizer>)oldView.GestureRecognizers;
+                    oldRecognizers.CollectionChanged -= _collectionChangedHandler;
+                }
+            }
+
+            if (e.NewElement != null) {
+                // hook
+                if (ElementGestureRecognizers != null) {
+                    ElementGestureRecognizers.CollectionChanged += _collectionChangedHandler;
+                    LoadRecognizers ();
+                }
+            }
+        }
+
+        void LoadRecognizers ()
+        {
+            if (ElementGestureRecognizers == null)
+                return;
+
+            foreach (var recognizer in ElementGestureRecognizers) {
+                if (_gestureRecognizers.ContainsKey (recognizer))
+                    continue;
+
+                var nativeRecognizer = GetNativeRecognizer (recognizer);
+                if (nativeRecognizer != null) {
+                    AddGestureRecognizer (_handler, nativeRecognizer);
+
+                    _gestureRecognizers[recognizer] = nativeRecognizer;
+                }
+            }
+
+            var toRemove = _gestureRecognizers.Keys.Where (key => !ElementGestureRecognizers.Contains (key)).ToArray ();
+            foreach (var gestureRecognizer in toRemove) {
+                var uiRecognizer = _gestureRecognizers[gestureRecognizer];
+                _gestureRecognizers.Remove (gestureRecognizer);
+
+                RemoveGestureRecognizer (_handler, uiRecognizer);
+                uiRecognizer.Dispose ();
+            }
+        }
+
+        protected virtual NativeGestureRecognizer GetNativeRecognizer (IGestureRecognizer recognizer)
+        {
+            if (recognizer == null)
+                return null;
+
+            var weakRecognizer = new WeakReference (recognizer);
+            var weakEventTracker = new WeakReference (this);
+
+            var tapRecognizer = recognizer as TapGestureRecognizer;
+            if (tapRecognizer != null) {
+                var returnAction = new TargetEventHandler ((s, e) => {
+                    var tapGestureRecognizer = weakRecognizer.Target as TapGestureRecognizer;
+                    var eventTracker = weakEventTracker.Target as EventTracker;
+                    var view = eventTracker?._renderer?.Element as View;
+
+                    if (tapGestureRecognizer != null && view != null)
+                        tapGestureRecognizer.SendTapped (view);
+                });
+                var uiRecognizer = new NativeGestureRecognizer {
+                    EventType = "click",
+                    Handler = returnAction,
+                };
+                return uiRecognizer;
+            }
+
+            return null;
+        }
+
+        static void AddGestureRecognizer (Element element, NativeGestureRecognizer recognizer)
+        {
+            element.AddEventListener (recognizer.EventType, recognizer.Handler);
+        }
+
+        static void RemoveGestureRecognizer (Element element, NativeGestureRecognizer recognizer)
+        {
+            element.RemoveEventListener (recognizer.EventType, recognizer.Handler);
+        }
+
+        public void LoadEvents (NativeView handler)
+        {
+            if (_disposed)
+                throw new ObjectDisposedException (null);
+
+            _handler = handler;
+            OnElementChanged (this, new VisualElementChangedEventArgs (null, _renderer.Element));
+        }
+
+        protected class NativeGestureRecognizer : IDisposable
+        {
+            public string EventType;
+            public TargetEventHandler Handler;
+            public void Dispose ()
+            {
+            }
+        }
+    }
+}

Ooui.Forms/Platform.cs

@@ -57,6 +57,10 @@ namespace Ooui.Forms
             MessagingCenter.Unsubscribe<Page, ActionSheetArguments> (this, Page.ActionSheetSignalName);
             MessagingCenter.Unsubscribe<Page, AlertArguments> (this, Page.AlertSignalName);
             MessagingCenter.Unsubscribe<Page, bool> (this, Page.BusySetSignalName);
+
+            DisposeModelAndChildrenRenderers (Page);
+            //foreach (var modal in _modals)
+                //DisposeModelAndChildrenRenderers (modal);
         }
 
         public static IVisualElementRenderer CreateRenderer (VisualElement element)
@@ -110,7 +114,29 @@ namespace Ooui.Forms
 
         void HandleChildRemoved (object sender, ElementEventArgs e)
         {
-            throw new NotImplementedException ();
+            var view = e.Element;
+            DisposeModelAndChildrenRenderers (view);
+        }
+
+        void DisposeModelAndChildrenRenderers (Xamarin.Forms.Element view)
+        {
+            IVisualElementRenderer renderer;
+            foreach (VisualElement child in view.Descendants ()) {
+                renderer = GetRenderer (child);
+                child.ClearValue (RendererProperty);
+
+                if (renderer != null) {
+                    //renderer.NativeView.RemoveFromSuperview ();
+                    renderer.Dispose ();
+                }
+            }
+
+            renderer = GetRenderer ((VisualElement)view);
+            if (renderer != null) {
+                //renderer.NativeView.RemoveFromSuperview ();
+                renderer.Dispose ();
+            }
+            view.ClearValue (RendererProperty);
         }
 
         void AddChild (VisualElement view)

Ooui.Forms/VisualElementRenderer.cs

@@ -38,6 +38,7 @@ namespace Ooui.Forms
 
         VisualElementRendererFlags _flags = VisualElementRendererFlags.AutoPackage | VisualElementRendererFlags.AutoTrack;
 
+        EventTracker _events;
         VisualElementPackager _packager;
         VisualElementTracker _tracker;
 
@@ -107,10 +108,10 @@ namespace Ooui.Forms
                 	_packager.Load ();
                 }
 
-                //if (AutoTrack && _events == null) {
-                //	_events = new EventTracker (this);
-                //	_events.LoadEvents (this);
-                //}
+                if (AutoTrack && _events == null) {
+                	_events = new EventTracker (this);
+                	_events.LoadEvents (this);
+                }
 
                 element.PropertyChanged += _propertyChangedHandler;
             }