1.添加获取UDid方法

lib/flutter_alibc.dart

@@ -276,7 +276,7 @@ class FlutterAlibc {
     _channel.invokeMethod("useAlipayNative", {"isNeed": isNeed});
   }
 
-  static Future<String> getUdid(bool isNeed) async {
+  static Future<String> getUdid() async {
     var map = await _channel.invokeMethod("getUdid");
     return map['udid'];
   }