订单结算优惠券增加，不可使用券，不可使用说明

lib/retrofit/data/settleOrderInfo.dart

@@ -254,6 +254,7 @@ class CouponListBean {
   bool isMaxCoupon;
   dynamic productList;
   bool isEx;
+  String usableReason;
 
 
   static CouponListBean fromJson(Map<String, dynamic> map) {
@@ -285,6 +286,7 @@ class CouponListBean {
     couponListBean.allProduct = map['allProduct'];
     couponListBean.isMaxCoupon = map['isMaxCoupon'];
     couponListBean.productList = map['productList'];
+    couponListBean.usableReason = map['usableReason'];
     return couponListBean;
   }
 
@@ -315,6 +317,7 @@ class CouponListBean {
     "allProduct": allProduct,
     "isMaxCoupon": isMaxCoupon,
     "productList": productList,
+    "usableReason":usableReason,
 
   };
 }

lib/settlement/settlement_view/coupon.dart

@@ -262,6 +262,31 @@ class _CouponWidget extends State<CouponWidget> {
                         ),
                       ],
                     ),
+                  if ((widget.couponList?.isEx ?? false) && ((widget.couponList?.usable??"") == ""))
+                    Row(
+                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                      children: [
+                        Expanded(child: Text(
+                          "不可用原因:",
+                          style: TextStyle(
+                            color: Color(0xFF353535),
+                            fontSize: 10.sp,
+                          ),
+                        )),
+                        Expanded(child: Align(
+                          alignment: Alignment.centerRight,
+                          child: Text(
+                            widget.couponList.usableReason ?? "",
+                            overflow: TextOverflow.ellipsis,
+                            style: TextStyle(
+                              color: Color(0xFF353535),
+                              fontSize: 10.sp,
+                            ),
+                          ),
+                        ))
+                        ,
+                      ],
+                    ),
                 ],
               ),
             ),