Fix DoubleTapped on touch (#7213)

DoubleTapped now can be triggered by touch
Fixed DoubleTapped triggering logic, previously it could be triggered only when you click twice, didn't work when you click 4 times,6, etc.
Fixed Tapped to be triggered only once when you double-click, now it triggers Tapped once and DoubleTapped once instead of triggering Tapped two times and DoubleTapped once.Matches UWP behaviour.

src/Avalonia.Input/Gestures.cs

@@ -6,6 +6,7 @@ namespace Avalonia.Input
 {
     public static class Gestures
     {
+        private static bool s_isDoubleTapped = false;
         public static readonly RoutedEvent<TappedEventArgs> TappedEvent = RoutedEvent.Register<TappedEventArgs>(
             "Tapped",
             RoutingStrategies.Bubble,
@@ -81,20 +82,23 @@ namespace Avalonia.Input
                 var e = (PointerPressedEventArgs)ev;
                 var visual = (IVisual)ev.Source;
 
-#pragma warning disable CS0618 // Type or member is obsolete
+                if (e.ClickCount <= 1)
-                var clickCount = e.ClickCount;
-#pragma warning restore CS0618 // Type or member is obsolete
-                if (clickCount <= 1)
                 {
+                    s_isDoubleTapped = false;
                     s_lastPress.SetTarget(ev.Source);
                 }
-                else if (clickCount == 2 && e.GetCurrentPoint(visual).Properties.IsLeftButtonPressed)
+                else if (e.ClickCount % 2 == 0 && e.GetCurrentPoint(visual).Properties.IsLeftButtonPressed)
                 {
                     if (s_lastPress.TryGetTarget(out var target) && target == e.Source)
                     {
+                        s_isDoubleTapped = true;
                         e.Source.RaiseEvent(new TappedEventArgs(DoubleTappedEvent, e));
                     }
                 }
+                else
+                {
+                    s_isDoubleTapped = false;
+                }
             }
         }
 
@@ -112,7 +116,9 @@ namespace Avalonia.Input
                         {
                             e.Source.RaiseEvent(new TappedEventArgs(RightTappedEvent, e));
                         }
-                        else
+                        //s_isDoubleTapped needed here to prevent invoking Tapped event when DoubleTapped is called.
+                        //This behaviour matches UWP behaviour.
+                        else if (s_isDoubleTapped == false)
                         {
                             e.Source.RaiseEvent(new TappedEventArgs(TappedEvent, e));
                         }

src/Avalonia.Input/PointerEventArgs.cs

@@ -114,7 +114,7 @@ namespace Avalonia.Input
 
     public class PointerPressedEventArgs : PointerEventArgs
     {
-        private readonly int _obsoleteClickCount;
+        private readonly int _clickCount;
 
         public PointerPressedEventArgs(
             IInteractive source,
@@ -123,15 +123,14 @@ namespace Avalonia.Input
             ulong timestamp,
             PointerPointProperties properties,
             KeyModifiers modifiers,
-            int obsoleteClickCount = 1)
+            int clickCount = 1)
             : base(InputElement.PointerPressedEvent, source, pointer, rootVisual, rootVisualPosition,
                 timestamp, properties, modifiers)
         {
-            _obsoleteClickCount = obsoleteClickCount;
+            _clickCount = clickCount;
         }
 
-        [Obsolete("Use DoubleTapped event or Gestures.DoubleRightTapped attached event")]
+        public int ClickCount => _clickCount;
-        public int ClickCount => _obsoleteClickCount;
 
         [Obsolete("Use PointerPressedEventArgs.GetCurrentPoint(this).Properties")]
         public MouseButton MouseButton => Properties.PointerUpdateKind.GetMouseButton();

src/Avalonia.Input/TouchDevice.cs

@@ -2,7 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using Avalonia.Input.Raw;
-using Avalonia.VisualTree;
+using Avalonia.Platform;
 
 namespace Avalonia.Input
 {
@@ -16,7 +16,9 @@ namespace Avalonia.Input
     {
         private readonly Dictionary<long, Pointer> _pointers = new Dictionary<long, Pointer>();
         private bool _disposed;
-        
+        private int _clickCount;
+        private Rect _lastClickRect;
+        private ulong _lastClickTime;
         KeyModifiers GetKeyModifiers(RawInputModifiers modifiers) =>
             (KeyModifiers)(modifiers & RawInputModifiers.KeyboardMask);
 
@@ -27,10 +29,10 @@ namespace Avalonia.Input
                 rv |= RawInputModifiers.LeftMouseButton;
             return rv;
         }
-        
+
         public void ProcessRawEvent(RawInputEventArgs ev)
         {
-            if(_disposed)
+            if (_disposed)
                 return;
             var args = (RawTouchEventArgs)ev;
             if (!_pointers.TryGetValue(args.TouchPointId, out var pointer))
@@ -43,16 +45,40 @@ namespace Avalonia.Input
                     PointerType.Touch, _pointers.Count == 0);
                 pointer.Capture(hit);
             }
-            
+
 
             var target = pointer.Captured ?? args.Root;
             if (args.Type == RawPointerEventType.TouchBegin)
             {
+                if (_pointers.Count > 1)
+                {
+                    _clickCount = 1;
+                    _lastClickTime = 0;
+                    _lastClickRect = new Rect();
+                }
+                else
+                {
+                    var settings = AvaloniaLocator.Current.GetService<IPlatformSettings>();
+                    if (settings == null)
+                    {
+                        throw new Exception("IPlatformSettings can not be null");
+                    }
+                    if (!_lastClickRect.Contains(args.Position)
+                        || ev.Timestamp - _lastClickTime > settings.DoubleClickTime.TotalMilliseconds)
+                    {
+                        _clickCount = 0;
+                    }
+                    ++_clickCount;
+                    _lastClickTime = ev.Timestamp;
+                    _lastClickRect = new Rect(args.Position, new Size())
+                        .Inflate(new Thickness(16, 16));
+                }
+
                 target.RaiseEvent(new PointerPressedEventArgs(target, pointer,
                     args.Root, args.Position, ev.Timestamp,
                     new PointerPointProperties(GetModifiers(args.InputModifiers, true),
                         PointerUpdateKind.LeftButtonPressed),
-                    GetKeyModifiers(args.InputModifiers)));
+                    GetKeyModifiers(args.InputModifiers), _clickCount));
             }
 
             if (args.Type == RawPointerEventType.TouchEnd)
@@ -84,12 +110,12 @@ namespace Avalonia.Input
                     GetKeyModifiers(args.InputModifiers)));
             }
 
-            
+
         }
 
         public void Dispose()
         {
-            if(_disposed)
+            if (_disposed)
                 return;
             var values = _pointers.Values.ToList();
             _pointers.Clear();
@@ -97,6 +123,6 @@ namespace Avalonia.Input
             foreach (var p in values)
                 p.Dispose();
         }
-        
+
     }
 }

tests/Avalonia.Input.UnitTests/TouchDeviceTests.cs

@@ -0,0 +1,272 @@
+using System;
+using Avalonia.Input.Raw;
+using Avalonia.Platform;
+using Avalonia.UnitTests;
+using Moq;
+using Xunit;
+
+namespace Avalonia.Input.UnitTests
+{
+    public class TouchDeviceTests
+    {
+        [Fact]
+        public void Tapped_Event_Is_Fired_With_Touch()
+        {
+            using (UnitTestApplication.Start(
+                new TestServices(inputManager: new InputManager())))
+            {
+                var root = new TestRoot();
+                var touchDevice = new TouchDevice();
+
+                var isTapped = false;
+                var executedTimes = 0;
+                root.Tapped += (a, e) =>
+                {
+                    isTapped = true;
+                    executedTimes++;
+                };
+                TapOnce(InputManager.Instance, touchDevice, root);
+                Assert.True(isTapped);
+                Assert.Equal(1, executedTimes);
+            }
+        }
+
+        [Fact]
+        public void DoubleTapped_Event_Is_Fired_With_Touch()
+        {
+            var platformSettingsMock = new Mock<IPlatformSettings>();
+            platformSettingsMock.Setup(x => x.DoubleClickTime).Returns(new TimeSpan(200));
+            AvaloniaLocator.CurrentMutable.BindToSelf(this)
+               .Bind<IPlatformSettings>().ToConstant(platformSettingsMock.Object);
+            using (UnitTestApplication.Start(
+                new TestServices(inputManager: new InputManager())))
+            {
+                var root = new TestRoot();
+                var touchDevice = new TouchDevice();
+
+                var isDoubleTapped = false;
+                var doubleTappedExecutedTimes = 0;
+                var tappedExecutedTimes = 0;
+                root.DoubleTapped += (a, e) =>
+                {
+                    isDoubleTapped = true;
+                    doubleTappedExecutedTimes++;
+                };
+                root.Tapped += (a, e) =>
+                {
+                    tappedExecutedTimes++;
+                };
+                TapOnce(InputManager.Instance, touchDevice, root);
+                TapOnce(InputManager.Instance, touchDevice, root, touchPointId: 1);
+                Assert.Equal(1, tappedExecutedTimes);
+                Assert.True(isDoubleTapped);
+                Assert.Equal(1, doubleTappedExecutedTimes);
+            }
+        }
+
+        [Theory]
+        [InlineData(1)]
+        [InlineData(2)]
+        [InlineData(3)]
+        [InlineData(4)]
+        [InlineData(5)]
+        public void PointerPressed_Counts_Clicks_Correctly(int clickCount)
+        {
+            var platformSettingsMock = new Mock<IPlatformSettings>();
+            platformSettingsMock.Setup(x => x.DoubleClickTime).Returns(new TimeSpan(200));
+            AvaloniaLocator.CurrentMutable.BindToSelf(this)
+               .Bind<IPlatformSettings>().ToConstant(platformSettingsMock.Object);
+            using (UnitTestApplication.Start(
+                new TestServices(inputManager: new InputManager())))
+            {
+                var root = new TestRoot();
+                var touchDevice = new TouchDevice();
+
+                var pointerPressedExecutedTimes = 0;
+                var pointerPressedClicks = 0;
+                root.PointerPressed += (a, e) =>
+                {
+                    pointerPressedClicks = e.ClickCount;
+                    pointerPressedExecutedTimes++;
+                };
+                for (int i = 0; i < clickCount; i++)
+                {
+                    TapOnce(InputManager.Instance, touchDevice, root, touchPointId: i);
+                }
+
+                Assert.Equal(clickCount, pointerPressedExecutedTimes);
+                Assert.Equal(pointerPressedClicks, clickCount);
+            }
+        }
+
+        [Fact]
+        public void DoubleTapped_Not_Fired_When_Click_Too_Late()
+        {
+            var platformSettingsMock = new Mock<IPlatformSettings>();
+            platformSettingsMock.Setup(x => x.DoubleClickTime).Returns(new TimeSpan(0, 0, 0, 0, 20));
+            AvaloniaLocator.CurrentMutable.BindToSelf(this)
+               .Bind<IPlatformSettings>().ToConstant(platformSettingsMock.Object);
+            using (UnitTestApplication.Start(
+                new TestServices(inputManager: new InputManager())))
+            {
+                var root = new TestRoot();
+                var touchDevice = new TouchDevice();
+
+                var isDoubleTapped = false;
+                var doubleTappedExecutedTimes = 0;
+                var tappedExecutedTimes = 0;
+                root.DoubleTapped += (a, e) =>
+                {
+                    isDoubleTapped = true;
+                    doubleTappedExecutedTimes++;
+                };
+                root.Tapped += (a, e) =>
+                {
+                    tappedExecutedTimes++;
+                };
+                TapOnce(InputManager.Instance, touchDevice, root);
+                TapOnce(InputManager.Instance, touchDevice, root, 21, 1);
+                Assert.Equal(2, tappedExecutedTimes);
+                Assert.False(isDoubleTapped);
+                Assert.Equal(0, doubleTappedExecutedTimes);
+            }
+        }
+
+        [Fact]
+        public void DoubleTapped_Not_Fired_When_Second_Click_Is_From_Different_Touch_Contact()
+        {
+            var tmp = new Mock<IPlatformSettings>();
+            tmp.Setup(x => x.DoubleClickTime).Returns(new TimeSpan(200));
+            AvaloniaLocator.CurrentMutable.BindToSelf(this)
+               .Bind<IPlatformSettings>().ToConstant(tmp.Object);
+            using (UnitTestApplication.Start(
+                new TestServices(inputManager: new InputManager())))
+            {
+                var root = new TestRoot();
+                var touchDevice = new TouchDevice();
+
+                var isDoubleTapped = false;
+                var doubleTappedExecutedTimes = 0;
+                var tappedExecutedTimes = 0;
+                root.DoubleTapped += (a, e) =>
+                {
+                    isDoubleTapped = true;
+                    doubleTappedExecutedTimes++;
+                };
+                root.Tapped += (a, e) =>
+                {
+                    tappedExecutedTimes++;
+                };
+                SendXTouchContactsWithIds(InputManager.Instance, touchDevice, root, RawPointerEventType.TouchBegin, 0, 1);
+                SendXTouchContactsWithIds(InputManager.Instance, touchDevice, root, RawPointerEventType.TouchEnd, 0, 1);
+                Assert.Equal(2, tappedExecutedTimes);
+                Assert.False(isDoubleTapped);
+                Assert.Equal(0, doubleTappedExecutedTimes);
+            }
+        }
+
+        [Fact]
+        public void Click_Counting_Should_Work_Correctly_With_Few_Touch_Contacts()
+        {
+            var tmp = new Mock<IPlatformSettings>();
+            tmp.Setup(x => x.DoubleClickTime).Returns(new TimeSpan(200));
+            AvaloniaLocator.CurrentMutable.BindToSelf(this)
+               .Bind<IPlatformSettings>().ToConstant(tmp.Object);
+            using (UnitTestApplication.Start(
+                new TestServices(inputManager: new InputManager())))
+            {
+                var root = new TestRoot();
+                var touchDevice = new TouchDevice();
+
+                var pointerPressedExecutedTimes = 0;
+                var tappedExecutedTimes = 0;
+                var isDoubleTapped = false;
+                var doubleTappedExecutedTimes = 0;
+                root.PointerPressed += (a, e) =>
+                {
+                    pointerPressedExecutedTimes++;
+                    switch (pointerPressedExecutedTimes)
+                    {
+                        case <= 2:
+                            Assert.True(e.ClickCount == 1);
+                            break;
+                        case 3:
+                            Assert.True(e.ClickCount == 2);
+                            break;
+                        case 4:
+                            Assert.True(e.ClickCount == 3);
+                            break;
+                        case 5:
+                            Assert.True(e.ClickCount == 4);
+                            break;
+                        case 6:
+                            Assert.True(e.ClickCount == 5);
+                            break;
+                        case 7:
+                            Assert.True(e.ClickCount == 1);
+                            break;
+                        case 8:
+                            Assert.True(e.ClickCount == 1);
+                            break;
+                        case 9:
+                            Assert.True(e.ClickCount == 2);
+                            break;
+                        default:
+                            break;
+                    }
+                };
+                root.DoubleTapped += (a, e) =>
+                {
+                    isDoubleTapped = true;
+                    doubleTappedExecutedTimes++;
+                };
+                root.Tapped += (a, e) =>
+                {
+                    tappedExecutedTimes++;
+                };
+                SendXTouchContactsWithIds(InputManager.Instance, touchDevice, root, RawPointerEventType.TouchBegin, 0, 1);
+                SendXTouchContactsWithIds(InputManager.Instance, touchDevice, root, RawPointerEventType.TouchEnd, 0, 1);
+                TapOnce(InputManager.Instance, touchDevice, root, touchPointId: 2);
+                TapOnce(InputManager.Instance, touchDevice, root, touchPointId: 3);
+                TapOnce(InputManager.Instance, touchDevice, root, touchPointId: 4);
+                SendXTouchContactsWithIds(InputManager.Instance, touchDevice, root, RawPointerEventType.TouchBegin, 5, 6, 7);
+                SendXTouchContactsWithIds(InputManager.Instance, touchDevice, root, RawPointerEventType.TouchEnd, 5, 6, 7);
+                TapOnce(InputManager.Instance, touchDevice, root, touchPointId: 8);
+                Assert.Equal(6, tappedExecutedTimes);
+                Assert.Equal(9, pointerPressedExecutedTimes);
+                Assert.True(isDoubleTapped);
+                Assert.Equal(3, doubleTappedExecutedTimes);
+
+            }
+        }
+        private static void SendXTouchContactsWithIds(IInputManager inputManager, TouchDevice device, IInputRoot root, RawPointerEventType type, params long[] touchPointIds)
+        {
+            for (int i = 0; i < touchPointIds.Length; i++)
+            {
+                inputManager.ProcessInput(new RawTouchEventArgs(device, 0,
+                                                              root,
+                                                              type,
+                                                              new Point(0, 0),
+                                                              RawInputModifiers.None,
+                                                              touchPointIds[i]));
+            }
+        }
+
+
+        private static void TapOnce(IInputManager inputManager, TouchDevice device, IInputRoot root, ulong timestamp = 0, long touchPointId = 0)
+        {
+            inputManager.ProcessInput(new RawTouchEventArgs(device, timestamp,
+                                               root,
+                                               RawPointerEventType.TouchBegin,
+                                               new Point(0, 0),
+                                               RawInputModifiers.None,
+                                               touchPointId));
+            inputManager.ProcessInput(new RawTouchEventArgs(device, timestamp,
+                                                root,
+                                                RawPointerEventType.TouchEnd,
+                                                new Point(0, 0),
+                                                RawInputModifiers.None,
+                                                touchPointId));
+        }
+    }
+}