I'm building a WPF apps that have to support touch manipulation. In this case, it's "click" event. I created a class to add click behavior to a FrameworkElement. The problem is that when I touch the screen ( TouchDown ) and then move a bit ( around 10 pixels ) or do a fast tap, the event MouseLeftButtonDown is also fired .. I don't have found the source of the problem, so I'm asking here some help. If you have any questions, don't hesitate. Thanks in advance.
public class ClickBehavior : Behavior
{
private const double MAXIMUM_DELTA_CHANGED = 10.0;
public const int MAXIMUM_TOUCH_DURATION = 1000;
private bool pressed = false;
private Position initialPosition;
private DateTime startDate;
public ClickBehavior(FrameworkElement _fe)
: base(_fe)
{
fe.MouseLeftButtonDown += OnMouseLeftButtonDown;
fe.TouchDown += OnTouchDown;
}
public static readonly RoutedEvent ClickEvent = EventManager.RegisterRoutedEvent(
"Click", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(FrameworkElement));
private void RaiseClickEvent()
{
RoutedEventArgs newEventArgs = new RoutedEventArgs(ClickEvent);
fe.RaiseEvent(newEventArgs);
}
#region touchHandle
private void StopTouchManipulation()
{
pressed = false;
initialPosition = null;
fe.TouchUp -= OnTouchUp;
fe.TouchLeave -= OnTouchLeave;
fe.TouchEnter -= OnTouchEnter;
fe.TouchMove -= OnTouchMove;
}
private void OnTouchDown(object sender, TouchEventArgs e)
{
DebugManager.Debug("Touch Down");
e.Handled = true;
pressed = true;
initialPosition = new Position(Mouse.GetPosition(fe));
startDate = DateTime.Now;
fe.TouchUp += OnTouchUp;
fe.TouchLeave += OnTouchLeave;
fe.TouchEnter += OnTouchEnter;
fe.TouchMove += OnTouchMove;
}
private void OnTouchUp(object sender, TouchEventArgs e)
{
e.Handled = true;
if ((DateTime.Now - startDate).TotalMilliseconds < MAXIMUM_TOUCH_DURATION)
{
if (pressed)
{
RaiseClickEvent();
}
}
StopTouchManipulation();
}
private void OnTouchLeave(object sender, TouchEventArgs e)
{
e.Handled = true;
StopTouchManipulation();
}
private void OnTouchEnter(object sender, TouchEventArgs e)
{
e.Handled = true;
StopTouchManipulation();
}
private void OnTouchMove(object sender, TouchEventArgs e)
{
e.Handled = true;
if (pressed)
{
Position pos = new Position(Mouse.GetPosition(fe));
double distance = Position.GetDistance(initialPosition, pos);
if (distance >= MAXIMUM_DELTA_CHANGED)
{
StopTouchManipulation();
}
}
}
#endregion
#region mouseHandle
private void StopClickManipulation()
{
pressed = false;
initialPosition = null;
fe.MouseLeftButtonUp -= OnMouseLeftButtonUp;
fe.MouseEnter -= OnMouseEnter;
fe.MouseLeave -= OnMouseLeave;
fe.MouseMove -= OnMouseMove;
}
private void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
DebugManager.Debug("Mouse Left Down");
e.Handled = true;
pressed = true;
initialPosition = new Position(Mouse.GetPosition(fe));
fe.MouseLeftButtonUp += OnMouseLeftButtonUp;
fe.MouseEnter += OnMouseEnter;
fe.MouseLeave += OnMouseLeave;
fe.MouseMove += OnMouseMove;
}
private void OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
e.Handled = true;
if (pressed)
{
RaiseClickEvent();
}
StopClickManipulation();
}
private void OnMouseEnter(object sender, MouseEventArgs e)
{
e.Handled = true;
StopClickManipulation();
}
private void OnMouseLeave(object sender, MouseEventArgs e)
{
e.Handled = true;
StopClickManipulation();
}
private void OnMouseMove(object sender, MouseEventArgs e)
{
e.Handled = true;
if (pressed)
{
Position pos = new Position(Mouse.GetPosition(fe));
double distance = Position.GetDistance(initialPosition, pos);
if ( distance>= MAXIMUM_DELTA_CHANGED)
{
StopClickManipulation();
}
}
}
#endregion
}
The line
fe.IsManipulationEnable = true;
in the constructor have done the trick :
public class Behavior<T> where T : FrameworkElement
{
public static bool IsManipulating = false;
protected T fe;
private bool enable;
public bool Enable
{
get
{
return enable;
}
set
{
bool changed = false;
if (enable != value)
{
changed = true;
}
enable = value;
if (changed)
{
if (enable)
{
Enable_Partial();
}
else
{
Disable_Partial();
}
}
}
}
public Behavior(T _fe)
{
fe = _fe;
fe.IsManipulationEnabled = true;
enable = true;
}
protected virtual void Enable_Partial()
{
}
protected virtual void Disable_Partial()
{
}
}
public class ClickBehavior : Behavior<FrameworkElement>
{
public const double MAXIMUM_TOUCH_DELTA_CHANGED = 5;
public const double MAXIMUM_MOUSE_DELTA_CHANGED = 10;
public const int MAXIMUM_TOUCH_DURATION = 333;
private Position initialPosition;
private DateTime startDate;
public ClickBehavior(FrameworkElement _fe)
: base(_fe)
{
fe.MouseLeftButtonDown += OnMouseLeftButtonDown;
fe.TouchDown += OnTouchDown;
}
public static readonly RoutedEvent ClickEvent = EventManager.RegisterRoutedEvent(
"Click", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(FrameworkElement));
// This method raises the Tap event
private void RaiseClickEvent()
{
RoutedEventArgs newEventArgs = new RoutedEventArgs(ClickEvent);
fe.RaiseEvent(newEventArgs);
}
#region touch handle
private void StopTouchManipulation(TouchEventArgs e)
{
initialPosition = null;
fe.TouchUp -= OnTouchUp;
fe.TouchLeave -= OnTouchLeave;
MainWindow.Current.TouchMove -= OnTouchMove;
}
private void OnTouchDown(object sender, TouchEventArgs e)
{
if (Enable)
{
initialPosition = new Position(e.GetTouchPoint(MainWindow.Current));
startDate = DateTime.Now;
fe.TouchUp += OnTouchUp;
fe.TouchLeave += OnTouchLeave;
MainWindow.Current.TouchMove += OnTouchMove;
}
}
private void OnTouchUp(object sender, TouchEventArgs e)
{
TouchPoint tp = e.GetTouchPoint(fe);
Rect bounds = new Rect(new Point(0, 0), fe.RenderSize);
if (bounds.Contains(tp.Position))
{
if ((DateTime.Now - startDate).TotalMilliseconds < MAXIMUM_TOUCH_DURATION)
{
e.Handled = true;
RaiseClickEvent();
}
}
StopTouchManipulation(e);
}
private void OnTouchLeave(object sender, TouchEventArgs e)
{
StopTouchManipulation(e);
}
private void OnTouchMove(object sender, TouchEventArgs e)
{
Position pos = new Position(e.GetTouchPoint(MainWindow.Current));
double distance = Position.GetDistance(initialPosition, pos);
if (distance >= MAXIMUM_TOUCH_DELTA_CHANGED)
{
StopTouchManipulation(e);
}
}
#endregion
#region mouse handle
private void StopClickManipulation()
{
initialPosition = null;
fe.MouseLeftButtonUp -= OnMouseLeftButtonUp;
fe.MouseLeave -= OnMouseLeave;
MainWindow.Current.MouseMove -= OnMouseMove;
}
private void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (Enable)
{
initialPosition = new Position(Mouse.GetPosition(MainWindow.Current));
fe.MouseLeftButtonUp += OnMouseLeftButtonUp;
fe.MouseLeave += OnMouseLeave;
MainWindow.Current.MouseMove += OnMouseMove;
}
}
private void OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
e.Handled = true;
RaiseClickEvent();
StopClickManipulation();
}
private void OnMouseEnter(object sender, MouseEventArgs e)
{
StopClickManipulation();
}
private void OnMouseLeave(object sender, MouseEventArgs e)
{
StopClickManipulation();
}
private void OnMouseMove(object sender, MouseEventArgs e)
{
Position pos = new Position(Mouse.GetPosition(MainWindow.Current));
double distance = Position.GetDistance(initialPosition, pos);
if (distance >= MAXIMUM_MOUSE_DELTA_CHANGED)
{
StopClickManipulation();
}
}
#endregion
}