new add ios support

ios/Classes/JsonUtil.swift

@@ -0,0 +1,27 @@
+//
+//  JsonUtil.swift
+//  Runner
+//
+//  Created by z1u24 on 2021/6/28.
+//
+
+import Foundation
+
+public class JsonUtil {
+    
+    public static func toString(object: AnyObject?)->String{
+        if object == nil {
+            return "";
+        }
+        if object is String{
+            let s = object as! String
+            let b = s.replacingOccurrences(of: "\"", with: "\\\"")
+            let a = "\"\(b)\""
+            return a
+        }
+        let data = try? JSONSerialization.data(withJSONObject: object!, options: JSONSerialization.WritingOptions.init(rawValue: 0))
+        let jsonStr = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
+        return jsonStr! as String
+    }
+    
+}