fix:when calling pay on ios,the handler crashed

example/lib/main.dart

@@ -55,7 +55,7 @@ class ShareSelectorPage extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return Center(
-      child: new Column(
+      child: new ListView(
         children: <Widget>[
           Padding(
             padding: const EdgeInsets.all(8.0),

example/lib/send_auth.dart

@@ -32,7 +32,9 @@ class _SendAuthPageState extends State<SendAuthPage> {
           OutlineButton(
             onPressed: () {
               _fluwx.sendAuth(new WeChatSendAuthModel(
-                  scope: "snsapi_userinfo", state: "wechat_sdk_demo_test"));
+                  scope: "snsapi_userinfo", state: "wechat_sdk_demo_test")).then((data){
+                    print("-------->$data");
+              });
             },
             child: const Text("send auth"),
           ),

ios/Classes/wechat/WXApiRequestHandler.m

@@ -377,14 +377,10 @@
     return [WXApi sendReq:chooseInvoiceReq];
 }
 
-- (BOOL)sendPayment:(NSString *)appId
-          PartnerId:(NSString *)partnerId
-           PrepayId:(NSString *)prepayId
-           NonceStr:(NSString *)nonceStr
-          Timestamp:(UInt32)timestamp
-            Package:(NSString *)package
-               Sign:(NSString *)sign
-{
+
+
++ (BOOL)sendPayment:(NSString *)appId PartnerId:(NSString *)partnerId PrepayId:(NSString *)prepayId NonceStr:(NSString *)nonceStr Timestamp:(UInt32)timestamp Package:(NSString *)package Sign:(NSString *)sign {
+
     PayReq *req = [[PayReq alloc] init];
     req.partnerId = partnerId;
     req.prepayId = prepayId;
@@ -397,6 +393,6 @@
 
 
     return [WXApi sendReq:req];
-
 }
+
 @end