Merge pull request #346 from donandren/iostext

Text handling in iOS

src/iOS/Perspex.iOS/Perspex.iOS.csproj

@@ -42,6 +42,7 @@
     <Compile Include="PlatformSettings.cs" />
     <Compile Include="PlatformThreadingInterface.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Specific\KeyboardEventsHelper.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\Perspex.Animation\Perspex.Animation.csproj">

src/iOS/Perspex.iOS/PerspexView.cs

@@ -14,26 +14,41 @@ using Perspex.Media;
 using Perspex.Platform;
 using Perspex.Skia.iOS;
 using UIKit;
+using Perspex.iOS.Specific;
+using ObjCRuntime;
 
 namespace Perspex.iOS
 {
+    [Adopts("UIKeyInput")]
     class PerspexView : SkiaView, IWindowImpl
     {
         private readonly UIWindow _window;
         private readonly UIViewController _controller;
         private IInputRoot _inputRoot;
+        private readonly KeyboardEventsHelper<PerspexView> _keyboardHelper;
 
         public PerspexView(UIWindow window, UIViewController controller) : base(onFrame => PlatformThreadingInterface.Instance.Render = onFrame)
         {
             if (controller == null) throw new ArgumentNullException(nameof(controller));
             _window = window;
             _controller = controller;
+            _keyboardHelper = new KeyboardEventsHelper<PerspexView>(this);
             AutoresizingMask = UIViewAutoresizing.All;
             AutoFit();
             UIApplication.Notifications.ObserveDidChangeStatusBarOrientation(delegate { AutoFit(); });
             UIApplication.Notifications.ObserveDidChangeStatusBarFrame(delegate { AutoFit(); });
         }
 
+        [Export("hasText")]
+        bool HasText => _keyboardHelper.HasText();
+
+        [Export("insertText:")]
+        void InsertText(string text) => _keyboardHelper.InsertText(text);
+
+        [Export("deleteBackward")]
+        void DeleteBackward() => _keyboardHelper.DeleteBackward();
+
+        public override bool CanBecomeFirstResponder => _keyboardHelper.CanBecomeFirstResponder();
 
         void AutoFit()
         {
@@ -89,6 +104,7 @@ namespace Perspex.iOS
 
         public void Show()
         {
+            _keyboardHelper.ActivateAutoShowKeybord();
         }
 
         public Size MaxClientSize => Bounds.Size.ToPerspex();
@@ -152,8 +168,14 @@ namespace Perspex.iOS
                         RawMouseEventType.Move, location, InputModifiers.LeftMouseButton));
                 else
                 {
-                    Input?.Invoke(new RawMouseWheelEventArgs(PerspexAppDelegate.MouseDevice, (uint) touch.Timestamp,
-                        _inputRoot, location, location - _touchLastPoint, InputModifiers.LeftMouseButton));
+                    double x = location.X - _touchLastPoint.X;
+                    double y = location.Y - _touchLastPoint.Y;
+                    double correction = 0.02;
+                    var scale = PerspexLocator.Current.GetService<IPlatformSettings>().RenderScalingFactor;
+                    scale = 1;
+
+                    Input?.Invoke(new RawMouseWheelEventArgs(PerspexAppDelegate.MouseDevice, (uint)touch.Timestamp,
+                        _inputRoot, location, new Vector(x * correction / scale, y * correction / scale), InputModifiers.LeftMouseButton));
                 }
                 _touchLastPoint = location;
             }

src/iOS/Perspex.iOS/Specific/KeyboardEventsHelper.cs

@@ -0,0 +1,147 @@
+using ObjCRuntime;
+using Perspex.Controls;
+using Perspex.Input;
+using Perspex.Input.Raw;
+using Perspex.Platform;
+using System;
+using System.ComponentModel;
+using System.Linq;
+using UIKit;
+
+namespace Perspex.iOS.Specific
+{
+    /// <summary>
+    /// In order to have properly handle of keyboard event in iOS View should already made some things in the View:
+    /// 1. Adopt the UIKeyInput protocol - add [Adopts("UIKeyInput")] to your view class
+    /// 2. Implement all the methods required by UIKeyInput:
+    ///     2.1  Implement HasText
+    ///             example:
+    ///                 [Export("hasText")]
+    ///                 bool HasText => _keyboardHelper.HasText()
+    ///     2.2   Implement InsertText
+    ///            example:
+    ///                [Export("insertText:")]
+    ///                void InsertText(string text) => _keyboardHelper.InsertText(text);
+    ///     2.3   Implement InsertText
+    ///            example:
+    ///               [Export("deleteBackward")]
+    ///               void DeleteBackward() => _keyboardHelper.DeleteBackward();
+    /// 3.Let iOS know that this can become a first responder:
+    ///            public override bool CanBecomeFirstResponder => _keyboardHelper.CanBecomeFirstResponder();
+    ///            or
+    ///            public override bool CanBecomeFirstResponder { get { return true; } }
+    ///
+    /// 4. To show keyboard:
+    ///             view.BecomeFirstResponder();
+    /// 5. To hide keyboard
+    ///             view.ResignFirstResponder();
+    /// </summary>
+    /// <typeparam name="TView">View that needs keyboard events and show/hide keyboard</typeparam>
+    internal class KeyboardEventsHelper<TView> where TView : UIView, IWindowImpl
+    {
+        private TView _view;
+        private IInputElement _lastFocusedElement;
+
+        public KeyboardEventsHelper(TView view)
+        {
+            _view = view;
+
+            var uiKeyInputAttribute = view.GetType().GetCustomAttributes(typeof(AdoptsAttribute), true).OfType<AdoptsAttribute>().Where(a => a.ProtocolType == "UIKeyInput").FirstOrDefault();
+
+            if (uiKeyInputAttribute == null) throw new NotSupportedException($"View class {typeof(TView).Name} should have class attribute - [Adopts(\"UIKeyInput\")] in order to access keyboard events!");
+
+            HandleEvents = true;
+        }
+
+        /// <summary>
+        /// HandleEvents in order to suspend keyboard notifications or resume it
+        /// </summary>
+        public bool HandleEvents { get; set; }
+
+        public bool HasText() => false;
+
+        public bool CanBecomeFirstResponder() => true;
+
+        public void DeleteBackward()
+        {
+            HandleKey(Key.Back, RawKeyEventType.KeyDown);
+            HandleKey(Key.Back, RawKeyEventType.KeyUp);
+        }
+
+        public void InsertText(string text)
+        {
+            var rawTextEvent = new RawTextInputEventArgs(KeyboardDevice.Instance, (uint)DateTime.Now.Ticks, text);
+            _view.Input(rawTextEvent);
+        }
+
+        private void HandleKey(Key key, RawKeyEventType type)
+        {
+            var rawKeyEvent = new RawKeyEventArgs(KeyboardDevice.Instance, (uint)DateTime.Now.Ticks, type, key, InputModifiers.None);
+            _view.Input(rawKeyEvent);
+        }
+
+        //currently not found a way to get InputModifiers state
+        //private static InputModifiers GetModifierKeys(object e)
+        //{
+        //    var im = InputModifiers.None;
+        //    //if (IsCtrlPressed) rv |= InputModifiers.Control;
+        //    //if (IsShiftPressed) rv |= InputModifiers.Shift;
+
+        //    return im;
+        //}
+
+        private bool NeedsKeyboard(IInputElement element)
+        {
+            //may be some other elements
+            return element is TextBox;
+        }
+
+        private void TryShowHideKeyboard(IInputElement element, bool value)
+        {
+            if (value)
+            {
+                _view.BecomeFirstResponder();
+            }
+            else
+            {
+                _view.ResignFirstResponder();
+            }
+        }
+
+        public void UpdateKeyboardState(IInputElement element)
+        {
+            var focusedElement = element;
+            bool oldValue = NeedsKeyboard(_lastFocusedElement);
+            bool newValue = NeedsKeyboard(focusedElement);
+
+            if (newValue != oldValue || newValue)
+            {
+                TryShowHideKeyboard(focusedElement, newValue);
+            }
+
+            _lastFocusedElement = element;
+        }
+
+        public void ActivateAutoShowKeybord()
+        {
+            var kbDevice = (KeyboardDevice.Instance as INotifyPropertyChanged);
+
+            //just in case we've called more than once the method
+            kbDevice.PropertyChanged -= KeyboardDevice_PropertyChanged;
+            kbDevice.PropertyChanged += KeyboardDevice_PropertyChanged;
+        }
+
+        private void KeyboardDevice_PropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(KeyboardDevice.FocusedElement))
+            {
+                UpdateKeyboardState(KeyboardDevice.Instance.FocusedElement);
+            }
+        }
+
+        public void Dispose()
+        {
+            HandleEvents = false;
+        }
+    }
+}