添加一个讲解如何使用MobX的Demo

MobXDemo1/assets/Script/StoreHello.ts

@@ -0,0 +1,21 @@
+import { observable, action } from "mobx";
+
+export class StoreHello {
+
+    private static instance: StoreHello = null;
+    public static getInstance() {
+        if (this.instance == null) {
+            this.instance = new StoreHello();
+        }
+        return this.instance;
+    }
+
+    @observable
+    public count: number = 0;
+
+    @action
+    public addCount() {
+        this.count = this.count || 0;
+        this.count++;
+    }
+}