Aligning button implementation with .NET IoT (#178)

Author: zoekdestep

devices/Button/Button.sln

@@ -5,7 +5,7 @@ VisualStudioVersion = 16.0.31702.278
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{11A8DD76-328B-46DF-9F39-F559912D0360}") = "Button", "Button.nfproj", "{954E94A7-75BA-4F8E-876F-E9C90BDCBEFE}"
 EndProject
-Project("{11A8DD76-328B-46DF-9F39-F559912D0360}") = "Samples", "Sample\Samples.nfproj", "{0B4708C9-EBFE-4B43-A79A-A9F6E7D7C486}"
+Project("{11A8DD76-328B-46DF-9F39-F559912D0360}") = "Samples", "samples\Samples.nfproj", "{0B4708C9-EBFE-4B43-A79A-A9F6E7D7C486}"
 EndProject
 Project("{11A8DD76-328B-46DF-9F39-F559912D0360}") = "Tests", "Tests\Tests.nfproj", "{83306802-B317-4851-9673-8CFBA215F749}"
 EndProject

devices/Button/ButtonHoldingState.cs

@@ -4,17 +4,17 @@
 namespace Iot.Device.Button
 {
     /// <summary>
-    /// The different button holding states.
+    /// The different states of a button that is being held.
     /// </summary>
     public enum ButtonHoldingState
     {
-        /// <summary>Started</summary>
+        /// <summary>Button holding started.</summary>
         Started,
 
-        /// <summary>Completed</summary>
+        /// <summary>Button holding completed.</summary>
         Completed,
 
-        /// <summary>Canceled</summary>
+        /// <summary>Button holding cancelled.</summary>
         Canceled,
     }
 }

devices/Button/GpioButton.cs

@@ -13,8 +13,9 @@ namespace Iot.Device.Button
     public class GpioButton : ButtonBase
     {
         private GpioController _gpioController;
+        private PinMode _pinMode;
+
         private int _buttonPin;
-        private bool _pullUp;
         private bool _shouldDispose;
 
         private bool _disposed = false;
@@ -23,32 +24,40 @@ public class GpioButton : ButtonBase
         /// Initialization of the button.
         /// </summary>
         /// <param name="buttonPin">GPIO pin of the button.</param>
-        /// <param name="pullUp">If the system is pullup (false = pulldown).</param>
+        /// <param name="pinMode">Pin mode of the system.</param>
         /// <param name="gpio">Gpio Controller.</param>
         /// <param name="shouldDispose">True to dispose the GpioController.</param>
-        public GpioButton(int buttonPin, bool pullUp = true, GpioController gpio = null, bool shouldDispose = true) : this(buttonPin, pullUp, TimeSpan.FromTicks(DefaultDoublePressTicks), TimeSpan.FromMilliseconds(DefaultHoldingMilliseconds), gpio, shouldDispose)
+        public GpioButton(int buttonPin, GpioController gpio = null, bool shouldDispose = true, PinMode pinMode = PinMode.InputPullUp) 
+            : this(buttonPin, TimeSpan.FromTicks(DefaultDoublePressTicks), TimeSpan.FromMilliseconds(DefaultHoldingMilliseconds), gpio, shouldDispose, pinMode)
         {
         }
 
         /// <summary>
         /// Initialization of the button.
         /// </summary>
         /// <param name="buttonPin">GPIO pin of the button.</param>
-        /// <param name="pullUp">If the system is pullup (false = pulldown).</param>
+        /// <param name="pinMode">Pin mode of the system.</param>
         /// <param name="doublePress">Max ticks between button presses to count as doublepress.</param>
         /// <param name="holding">Min ms a button is pressed to count as holding.</param>
         /// <param name="gpio">Gpio Controller.</param>
         /// <param name="shouldDispose">True to dispose the GpioController.</param>
-        public GpioButton(int buttonPin, bool pullUp, TimeSpan doublePress, TimeSpan holding, GpioController gpio = null, bool shouldDispose = true)
+        public GpioButton(int buttonPin, TimeSpan doublePress, TimeSpan holding, GpioController gpio = null, bool shouldDispose = true, PinMode pinMode = PinMode.InputPullUp)
             : base(doublePress, holding)
         {
             _gpioController = gpio ?? new GpioController();
             _shouldDispose = shouldDispose;
             _buttonPin = buttonPin;
-            _pullUp = pullUp;
+            _pinMode = pinMode;
 
-            _gpioController.OpenPin(_buttonPin, PinMode.Input);
-            _gpioController.RegisterCallbackForPinValueChangedEvent(_buttonPin, PinEventTypes.Falling | PinEventTypes.Rising, PinStateChanged);
+            if (_pinMode == PinMode.Input | _pinMode == PinMode.InputPullDown | _pinMode == PinMode.InputPullUp)
+            {
+                _gpioController.OpenPin(_buttonPin, _pinMode);
+                _gpioController.RegisterCallbackForPinValueChangedEvent(_buttonPin, PinEventTypes.Falling | PinEventTypes.Rising, PinStateChanged);
+            }
+            else
+            {
+                throw new ArgumentException("GPIO pin can only be set to input, not to output.");
+            }
         }
 
         /// <summary>
@@ -61,7 +70,7 @@ private void PinStateChanged(object sender, PinValueChangedEventArgs pinValueCha
             switch (pinValueChangedEventArgs.ChangeType)
             {
                 case PinEventTypes.Falling:
-                    if (_pullUp)
+                    if (_pinMode == PinMode.InputPullUp)
                     {
                         HandleButtonPressed();
                     }
@@ -72,7 +81,7 @@ private void PinStateChanged(object sender, PinValueChangedEventArgs pinValueCha
 
                     break;
                 case PinEventTypes.Rising:
-                    if (_pullUp)
+                    if (_pinMode == PinMode.InputPullUp)
                     {
                         HandleButtonReleased();
                     }
@@ -85,14 +94,6 @@ private void PinStateChanged(object sender, PinValueChangedEventArgs pinValueCha
             }
         }
 
-        /// <summary>
-        /// Cleanup.
-        /// </summary>
-        public new void Dispose()
-        {
-            Dispose(true);
-        }
-
         /// <summary>
         /// Internal cleanup.
         /// </summary>
@@ -106,19 +107,19 @@ protected override void Dispose(bool disposing)
 
             if (disposing)
             {
+                _gpioController.UnregisterCallbackForPinValueChangedEvent(_buttonPin, PinStateChanged);
                 if (_shouldDispose)
                 {
                     _gpioController?.Dispose();
                     _gpioController = null!;
                 }
                 else
                 {
-                    _gpioController.UnregisterCallbackForPinValueChangedEvent(_buttonPin, PinStateChanged);
                     _gpioController.ClosePin(_buttonPin);
                 }
 
-                base.Dispose(disposing);
-                _disposed = true;
+            base.Dispose(disposing);
+            _disposed = true;
             }
         }
     }