fix null safety error

lib/pages/things_page/fixed_submit_page.dart

@@ -85,7 +85,7 @@ class _FixedSubmitPageState extends State<FixedSubmitPage> {
       curve: Curves.easeInOutCubic,
       child: GestureDetector(
         onTap: () {
-          Get.to(() => FixedDetailPage(model.id));
+          Get.to(() => FixedDetailPage(model.id ?? 0));
         },
         child: Container(
           width: 686.w,

lib/pages/things_page/widget/fixed_detail_page.dart

@@ -21,7 +21,7 @@ import 'package:aku_community/widget/bee_scaffold.dart';
 import 'package:aku_community/widget/views/horizontal_image_view.dart';
 
 class FixedDetailPage extends StatefulWidget {
-  final int? id;
+  final int id;
   FixedDetailPage(
     this.id, {
     Key? key,
@@ -220,7 +220,8 @@ class _FixedDetailPageState extends State<FixedDetailPage> {
           ...model.appProcessRecordVo!
               .map((e) => Row(
                     children: [
-                      BeeMap.processClass[e.operationType!]!.text
+                      (BeeMap.processClass[e.operationType ?? 0] ?? '')
+                          .text
                           .color(ktextSubColor)
                           .size(28.sp)
                           .make(),

lib/utils/bee_map.dart

@@ -16,6 +16,7 @@ class BeeMap {
   };
 
   static Map<int, String> processClass = {
+    0: '未知',
     1: '报修时间',
     2: '管家分派',
     3: '师傅接单',