final work for article

Author: Naphier

.gitignore

@@ -28,3 +28,4 @@ sysinfo.txt
 # Builds
 *.apk
 *.unitypackage
+Assets/saves/

Assets/_Scenes.meta Assets/1_PlayerPrefs_Example.metaAssets/_Scenes.meta renamed to Assets/1_PlayerPrefs_Example.meta

@@ -0,0 +1,71 @@
+using UnityEngine;
+
+namespace EX1
+{
+	/// <summary>
+	/// Singleton - There should only ever be one DataService and it should persist
+	/// between scene loads.
+	/// This class is responsible for loading/saving data.
+	/// </summary>
+	public class DataService : MonoBehaviour
+	{
+		private static DataService _instance = null;
+		public static DataService Instance
+		{
+			get
+			{
+				// If the instance of this class doesn't exist
+				if (_instance == null)
+				{
+					// Check the scene for a Game Object with this class
+					_instance = FindObjectOfType<DataService>();
+
+					// If none is found in the scene then create a new Game Object
+					// and add this class to it.
+					if (_instance == null)
+					{
+						GameObject go = new GameObject(typeof(DataService).ToString());
+						_instance = go.AddComponent<DataService>();
+					}
+				}
+
+				return _instance;
+			}
+		}
+
+		public PlayerPrefsHandler prefs { get; private set; }
+
+		// When the scene first runs ensure that there is only one
+		// instance of this class. This allows us to add it to any scene and 
+		// not conflict with any pre-existing instance from a previous scene.
+		private void Awake()
+		{
+			if (Instance != this)
+			{
+				Destroy(this);
+			}
+			else
+			{
+				DontDestroyOnLoad(gameObject);
+
+				prefs = new PlayerPrefsHandler();
+				prefs.RestorePreferences();
+				// In Unity 5.4 OnLevelWasLoaded has been deprecated and the action
+				// now occurs through this callback.
+#if UNITY_5_4_OR_NEWER
+				SceneManager.sceneLoaded += OnLevelWasLoaded;
+#endif
+			}
+		}
+
+		/// <summary>
+		/// Ensure that the player preferences are applied to the new scene.
+		/// </summary>
+		// In Unity 5.4 OnLevelWasLoaded has been deprecated and the action
+		// now occurs through 'SceneManager.sceneLoaded' callback.
+		void OnLevelWasLoaded()
+		{
+			prefs.RestorePreferences();
+		}
+	}
+}