全局导航服务 --- fix2

src/service/app/navdata-service.ts

@@ -45,6 +45,16 @@ export interface NavDataElement {
  */
 export default class NavDataService {
 
+    /**
+     * 单例变量声明
+     *
+     * @private
+     * @static
+     * @type {NavDataService}
+     * @memberof NavDataService
+     */
+    private static navDataService: NavDataService;
+
     /**
      * 导航数据栈
      * 
@@ -69,6 +79,20 @@ export default class NavDataService {
         this.initNavData();
     }
 
+    /**
+     * 获取 NavDataService 单例对象
+     *
+     * @static
+     * @returns {NavDataService}
+     * @memberof NavDataService
+     */
+    public static getInstance(): NavDataService {
+        if (!NavDataService.navDataService) {
+            NavDataService.navDataService = new NavDataService();
+        }
+        return this.navDataService;
+    }
+
     /**
      * 初始化基础导航数据
      * 
@@ -123,7 +147,7 @@ export default class NavDataService {
     }
 
     /**
-     * 从导航数据栈中删除指定数据
+     * 从导航数据栈中删除指定数据及栈底数据
      * 
      * @memberof NavDataService
      */