Touch

Touch is the most common input system on mobile devices. Pointers are points on the device screen corresponding to finger touches. Devices with multi-touch functionality support multiple simultaneous pointers.

PointerDispatcher

The PointerDispatcher is a class used to track pointer events.

public abstract class PointerDispatcher
{
    public IList<PointerPoint> Points { get; }

    public event EventHandler<PointerEventArgs> PointerDown;
    public event EventHandler<PointerEventArgs> PointerUp;
    public event EventHandler<PointerEventArgs> PointerMove;
}

Points property gets a list of points detected inside the surface at the current frame.

PointerDown, PointerUp and PointerMove events are available to track touch and pointer points.

PointerPoint

The PointerPoint class give the following information:

Property	Description
Id	A number that is uniquely associated to this touch. It is usually given by the underliying platform.
Position	The pointer position in screen coordinates
State	Get the current pointer state. See Button States for more information.

Using PointerDispatcher

The PointerDispatcher can be found within the Display or Surface objects. The following sample code can be used to access the pointer dispatcher from a Component or Service.

[BindService]
protected GraphicsPresenter graphicsPresenter;

protected override void Update(TimeSpan time)
{
    PointerDispatcher pointerDispatcher = this.graphicsPresenter.FocusedDisplay?.PointerDispatcher;

    if (keyboardDispatcher == null)
    {
        return;
    }

    foreach (PointerPoint p in keyboardDispatcher.Points)
    {
        if (p.State == ButtonState.Pressing)
        {
            // Do something
        }
    }
}