diff options
Diffstat (limited to 'Xamarin.Forms.Platform.Android/InnerGestureListener.cs')
| -rw-r--r-- | Xamarin.Forms.Platform.Android/InnerGestureListener.cs | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/Xamarin.Forms.Platform.Android/InnerGestureListener.cs b/Xamarin.Forms.Platform.Android/InnerGestureListener.cs new file mode 100644 index 00000000..f83a1ac7 --- /dev/null +++ b/Xamarin.Forms.Platform.Android/InnerGestureListener.cs @@ -0,0 +1,146 @@ +using System; +using System.Collections.Generic; +using System.Linq; +using Android.Runtime; +using Android.Views; +using Object = Java.Lang.Object; + +namespace Xamarin.Forms.Platform.Android +{ + internal class InnerGestureListener : Object, GestureDetector.IOnGestureListener, GestureDetector.IOnDoubleTapListener + { + bool _isScrolling; + Func<bool> _scrollCompleteDelegate; + Func<float, float, int, bool> _scrollDelegate; + Func<int, bool> _scrollStartedDelegate; + Func<int, bool> _tapDelegate; + Func<int, IEnumerable<TapGestureRecognizer>> _tapGestureRecognizers; + + public InnerGestureListener(Func<int, bool> tapDelegate, Func<int, IEnumerable<TapGestureRecognizer>> tapGestureRecognizers, Func<float, float, int, bool> scrollDelegate, + Func<int, bool> scrollStartedDelegate, Func<bool> scrollCompleteDelegate) + { + if (tapDelegate == null) + throw new ArgumentNullException("tapDelegate"); + if (tapGestureRecognizers == null) + throw new ArgumentNullException("tapGestureRecognizers"); + if (scrollDelegate == null) + throw new ArgumentNullException("scrollDelegate"); + if (scrollStartedDelegate == null) + throw new ArgumentNullException("scrollStartedDelegate"); + if (scrollCompleteDelegate == null) + throw new ArgumentNullException("scrollCompleteDelegate"); + + _tapDelegate = tapDelegate; + _tapGestureRecognizers = tapGestureRecognizers; + _scrollDelegate = scrollDelegate; + _scrollStartedDelegate = scrollStartedDelegate; + _scrollCompleteDelegate = scrollCompleteDelegate; + } + + // This is needed because GestureRecognizer callbacks can be delayed several hundred milliseconds + // which can result in the need to resurect this object if it has already been disposed. We dispose + // eagerly to allow easier garbage collection of the renderer + internal InnerGestureListener(IntPtr handle, JniHandleOwnership ownership) : base(handle, ownership) + { + } + + bool GestureDetector.IOnDoubleTapListener.OnDoubleTap(MotionEvent e) + { + if (_tapDelegate == null || _tapGestureRecognizers == null) + return false; + return _tapDelegate(2); + } + + bool GestureDetector.IOnDoubleTapListener.OnDoubleTapEvent(MotionEvent e) + { + return false; + } + + bool GestureDetector.IOnDoubleTapListener.OnSingleTapConfirmed(MotionEvent e) + { + if (_tapDelegate == null || _tapGestureRecognizers == null) + return false; + + // optimization: only wait for a second tap if there is a double tap handler + if (!HasDoubleTapHandler()) + return false; + + return _tapDelegate(1); + } + + bool GestureDetector.IOnGestureListener.OnDown(MotionEvent e) + { + return false; + } + + bool GestureDetector.IOnGestureListener.OnFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) + { + EndScrolling(); + + return false; + } + + void GestureDetector.IOnGestureListener.OnLongPress(MotionEvent e) + { + } + + bool GestureDetector.IOnGestureListener.OnScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) + { + if (_scrollDelegate == null || e1 == null || e2 == null) + return false; + + if (!_isScrolling && _scrollStartedDelegate != null) + _scrollStartedDelegate(e2.PointerCount); + + _isScrolling = true; + + float totalX = e2.GetX() - e1.GetX(); + float totalY = e2.GetY() - e1.GetY(); + + return _scrollDelegate(totalX, totalY, e2.PointerCount); + } + + void GestureDetector.IOnGestureListener.OnShowPress(MotionEvent e) + { + } + + bool GestureDetector.IOnGestureListener.OnSingleTapUp(MotionEvent e) + { + if (_tapDelegate == null || _tapGestureRecognizers == null) + return false; + + // optimization: do not wait for a second tap if there is no double tap handler + if (HasDoubleTapHandler()) + return false; + + return _tapDelegate(1); + } + + protected override void Dispose(bool disposing) + { + if (disposing) + { + _tapDelegate = null; + _tapGestureRecognizers = null; + _scrollDelegate = null; + _scrollStartedDelegate = null; + _scrollCompleteDelegate = null; + } + + base.Dispose(disposing); + } + + void EndScrolling() + { + if (_isScrolling && _scrollCompleteDelegate != null) + _scrollCompleteDelegate(); + + _isScrolling = false; + } + + bool HasDoubleTapHandler() + { + return _tapGestureRecognizers(2).Any(); + } + } +}
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