add 小程序支付回调

application/expand/controller/Xcx.php

@@ -221,7 +221,7 @@ class Xcx extends BaseAuth
             $arr = ['total_fee', 'out_trade_no'];
             foreach ($arr as $key=>$value) {
                 if (!isset($params[$value])) {
-                    HelperService::returnJson(['code' => 400, 'msg' => "参数错误（$key）",'data'=>['baseParams'=>$param]]);
+                    HelperService::returnJson(['code' => 400, 'msg' => "参数错误（{$key}）",'data'=>['baseParams'=>$param]]);
                 }
             }