feat: Add data transfer to instance

Assets/JCSUnity/Scripts/Interfaces/JCS_Instance.cs

@@ -28,7 +28,7 @@ public abstract class JCS_Instance<T> : MonoBehaviour
     /// <summary>
     /// Singleton instance interface to keep the old instance.
     /// </summary>
-    public class JCS_InstanceOld<T> : JCS_Instance<T>
+    public abstract class JCS_InstanceOld<T> : JCS_Instance<T>
         where T : MonoBehaviour
     {
         /* Variables */
@@ -40,25 +40,43 @@ public class JCS_InstanceOld<T> : JCS_Instance<T>
         /// <summary>
         /// Check singleton for keep the old one.
         /// </summary>
-        /// <param name="_new"> Current instance. </param>
-        protected void CheckInstance(T _new)
+        /// <param name="_old"> old instance </param>
+        /// <param name="_new"> new instance </param>
+        protected void CheckInstance(T _old, T _new)
         {
-            // Destory the new one; and keep the old one.
             if (instance != null)
             {
+                // only if needed
+                TransferData(_old, _new);
+
+                // Destory the new one; and keep the old one.
                 Destroy(_new.gameObject);
+
                 return;
             }
 
             // Only assign once!
             instance = _new;
         }
+
+        /// <summary>
+        /// Instead of Unity Engine's scripting layer's DontDestroyOnLoad.
+        /// I would like to use own define to transfer the old instance
+        /// to the newer instance.
+        /// 
+        /// Every time when unity load the scene. The script have been
+        /// reset, in order not to lose the original setting.
+        /// transfer the data from old instance to new instance.
+        /// </summary>
+        /// <param name="_old"> old instance </param>
+        /// <param name="_new"> new instance </param>
+        protected abstract void TransferData(T _old, T _new);
     }
 
     /// <summary>
     /// Singleton instance interface to keep the new instance.
     /// </summary>
-    public class JCS_InstanceNew<T> : JCS_Instance<T>
+    public abstract class JCS_InstanceNew<T> : JCS_Instance<T>
         where T : MonoBehaviour
     {
         /* Variables */
@@ -70,15 +88,34 @@ public class JCS_InstanceNew<T> : JCS_Instance<T>
         /// <summary>
         /// Check singleton for keep the new one.
         /// </summary>
-        /// <param name="_new"> Current instance. </param>
-        protected void CheckInstance(T _new)
+        /// <param name="_old"> old instance </param>
+        /// <param name="_new"> new instance </param>
+        protected void CheckInstance(T _old, T _new)
         {
-            // Destory the old one!
             if (instance != null)
+            {
+                // only if needed
+                TransferData(_old, _new);
+
+                // Destory the old one!
                 Destroy(instance);
+            }
 
             // Assign the new one!
             instance = _new;
         }
+
+        /// <summary>
+        /// Instead of Unity Engine's scripting layer's DontDestroyOnLoad.
+        /// I would like to use own define to transfer the old instance
+        /// to the newer instance.
+        /// 
+        /// Every time when unity load the scene. The script have been
+        /// reset, in order not to lose the original setting.
+        /// transfer the data from old instance to new instance.
+        /// </summary>
+        /// <param name="_old"> old instance </param>
+        /// <param name="_new"> new instance </param>
+        protected abstract void TransferData(T _old, T _new);
     }
 }