GpioButtonInputProvider.cs

using System;
using System.Collections;
using System.Device.Gpio;

using nanoFramework.UI;
using nanoFramework.UI.Input;
using nanoFramework.UI.Threading;
using nanoFramework.Presentation;


namespace Tetris
{
	/// <summary>
	/// Uses the hardware provider to get the pins for handling button input.
	/// </summary>
	public sealed class GPIOButtonInputProvider
	{
		public readonly Dispatcher Dispatcher;

		//private ButtonPad[] buttons;
		private readonly ArrayList buttons;
		private readonly DispatcherOperationCallback callback;
		private readonly InputProviderSite site;
		private readonly PresentationSource source;
		private readonly GpioController Gpio = new GpioController();

		/// <summary>
		/// Maps GPIOs to Buttons that can be processed by 
		/// nanoFramework.Presentation.
		/// </summary>
		/// <param name="source"></param>
		public GPIOButtonInputProvider(PresentationSource source)
		{
			// Set the input source.
			this.source = source;

			// Register our object as an input source with the input manager and 
			// get back an InputProviderSite object which forwards the input 
			// report to the input manager, which then places the input in the 
			// staging area.
			site = InputManager.CurrentInputManager.RegisterInputProvider(this);

			// Create a delegate that refers to the InputProviderSite object's 
			// ReportInput method.
			callback = new DispatcherOperationCallback(delegate (object report)
			{
				InputReportArgs args = (InputReportArgs)report;
				return site.ReportInput(args.Device, args.Report);
			});

			Dispatcher = Dispatcher.CurrentDispatcher;

			this.buttons = new ArrayList();
		}

		/// <summary>
		/// Add a GPIO pin as a specific Button
		/// </summary>
		/// <param name="gpioPinNumber">GPIO pin number</param>
		/// <param name="button">Button that this pin represents</param>
		/// <param name="internalPullup">If true will enable the internal pull up on pin ( SetDriveMode = InputPullUp )

		public void AddButton(int gpioPinNumber, Button button, bool internalPullup)
		{
			GpioPin pin = Gpio.OpenPin(gpioPinNumber);


			pin.SetPinMode(internalPullup ? PinMode.InputPullUp : PinMode.Input);
			pin.DebounceTimeout = new TimeSpan(0, 0, 0, 0, 50);

			this.buttons.Add(new ButtonPad(this, button, pin));
		}

		/// <summary>
		/// Represents a button pad on the emulated device, containing five 
		/// buttons for user input. 
		/// </summary>
		internal class ButtonPad : IDisposable
		{
			private readonly Button button;
			private readonly GPIOButtonInputProvider sink;
			private readonly ButtonDevice buttonDevice = InputManager.CurrentInputManager.ButtonDevice;

			/// <summary>
			/// Constructs a ButtonPad object that handles the  
			/// hardware's button interrupts.
			/// </summary>
			/// <param name="sink"></param>
			/// <param name="button"></param>
			/// <param name="pin"></param>
			public ButtonPad(GPIOButtonInputProvider sink, Button button, GpioPin pin)
			{
				this.sink = sink;
				this.button = button;
				pin.ValueChanged += Pin_ValueChanged;
			}

			private void Pin_ValueChanged(object sender, PinValueChangedEventArgs e)
			{
				RawButtonActions action = (e.ChangeType == PinEventTypes.Falling) ? RawButtonActions.ButtonUp : RawButtonActions.ButtonDown;

				// Create a time, should be from the pin_ValueChanged event.
				DateTime time = DateTime.UtcNow;

				RawButtonInputReport report = new RawButtonInputReport(sink.source, time, button, action);

				// Queue the button press to the input provider site.
				sink.Dispatcher.BeginInvoke(sink.callback, new InputReportArgs(buttonDevice, report));
			}

			protected virtual void Dispose(bool disposing)
			{
				if (disposing)
				{
				}
			}

			public void Dispose()
			{
				Dispose(true);
				GC.SuppressFinalize(this);
			}

		}
	}
}