check universal link when register

lib/src/fluwx_iml.dart

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 import 'dart:async';
+import 'dart:io';
 import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
@@ -145,6 +146,13 @@ Future registerWxApi(
     bool doOnIOS: true,
     bool doOnAndroid: true,
     String universalLink}) async {
+  if (doOnIOS && Platform.isIOS) {
+    if (universalLink.trim().isEmpty || !universalLink.startsWith("https")) {
+      throw ArgumentError.value(universalLink,
+          "your universal link is illegal, see https://developers.weixin.qq.com/doc/oplatform/Mobile_App/Access_Guide/iOS.html for detail");
+    }
+  }
+
   return await _channel.invokeMethod("registerApp", {
     "appId": appId,
     "iOS": doOnIOS,
@@ -288,7 +296,8 @@ Future sendAuth({String openId, @required String scope, String state}) async {
 /// Once AuthCode got, you need to request Access_Token
 /// For more information please visit：
 /// * https://open.weixin.qq.com/cgi-bin/showdocument?action=dir_list&t=resource/res_list&verify=1&id=open1419317851&token=
-Future sendWeChatAuth({String openId, @required String scope, String state}) async {
+Future sendWeChatAuth(
+    {String openId, @required String scope, String state}) async {
   // "scope": scope, "state": state, "openId": openId
 
   assert(scope != null && scope.trim().isNotEmpty);
@@ -359,13 +368,11 @@ Future stopAuthByQRCode() async {
   return await _channel.invokeMethod("stopAuthByQRCode");
 }
 
-
 /// stop auth
 Future stopWeChatAuthByQRCode() async {
   return await _channel.invokeMethod("stopAuthByQRCode");
 }
 
-
 /// open mini-program
 /// see [WXMiniProgramType]
 @Deprecated("use launchWeChatMiniProgram instead")
@@ -395,7 +402,6 @@ Future launchWeChatMiniProgram(
   });
 }
 
-
 /// true if WeChat is installed,otherwise false.
 /// However,the following key-value must be added into your info.plist since iOS 9:
 /// <key>LSApplicationQueriesSchemes</key>
@@ -437,8 +443,6 @@ Future pay(
   });
 }
 
-
-
 /// params are from server
 Future payWithWeChat(
     {@required String appId,
@@ -463,7 +467,6 @@ Future payWithWeChat(
   });
 }
 
-
 /// subscribe message
 @Deprecated("use subscribeWeChatMsg instead")
 Future subscribeMsg({
@@ -532,7 +535,6 @@ Future autoDeDuct(
   });
 }
 
-
 /// please read official docs.
 Future autoDeDuctWeChat(
     {@required String appId,