diff --git a/analysis_options.yaml b/analysis_options.yaml
new file mode 100644
index 00000000..a686c1b4
--- /dev/null
+++ b/analysis_options.yaml
@@ -0,0 +1,14 @@
+# Defines a default set of lint rules enforced for
+# projects at Google. For details and rationale,
+# see https://github.com/dart-lang/pedantic#enabled-lints.
+include: package:pedantic/analysis_options.yaml
+
+# For lint rules and documentation, see http://dart-lang.github.io/linter/lints.
+# Uncomment to specify additional rules.
+# linter:
+#   rules:
+#     - camel_case_types
+
+analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
diff --git a/lib/api/user_api.dart b/lib/api/user_api.dart
index e994879b..5ba22f56 100755
--- a/lib/api/user_api.dart
+++ b/lib/api/user_api.dart
@@ -1,5 +1,4 @@
 import 'dart:io';
-import 'dart:convert';
 
 import 'package:flutter/material.dart';
 import 'package:extended_image/extended_image.dart';
@@ -16,12 +15,12 @@ class UserAPI {
 
   static List<Cookie> cookiesForJWGL;
 
-  static Future login(Map<String, dynamic> params) async {
-    return NetUtils.tokenDio.post(API.login, data: params);
+  static Future<Response<T>> login<T>(Map<String, dynamic> params) async {
+    return NetUtils.tokenDio.post<T>(API.login, data: params);
   }
 
-  static void logout(context) async {
-    final confirm = await ConfirmationBottomSheet.show(
+  static Future<void> logout(BuildContext context) async {
+    final bool confirm = await ConfirmationBottomSheet.show(
       context,
       title: '退出登录',
       showConfirm: true,
@@ -32,7 +31,7 @@ class UserAPI {
     }
   }
 
-  static UserTag createUserTag(tagData) => UserTag(
+  static UserTag createUserTag(Map<String, dynamic> tagData) => UserTag(
         id: tagData['id'],
         name: tagData['tagname'],
       );
@@ -74,13 +73,13 @@ class UserAPI {
     avatarLastModified = DateTime.now().millisecondsSinceEpoch;
   }
 
-  static Future getUserInfo({int uid}) async {
+  static Future<dynamic> getUserInfo<T>({int uid}) async {
     if (uid == null) {
       return currentUser;
     } else {
       return NetUtils.getWithCookieAndHeaderSet(
         API.userInfo,
-        data: {'uid': uid},
+        data: <String, dynamic>{'uid': uid},
       );
     }
   }
@@ -124,27 +123,22 @@ class UserAPI {
   static Future getNotifications() async => NetUtils.getWithCookieAndHeaderSet(API.postUnread);
 
   static Future follow(int uid) async {
-    NetUtils.postWithCookieAndHeaderSet('${API.userRequestFollow}$uid').then((response) {
-      return NetUtils.postWithCookieAndHeaderSet(
-        API.userFollowAdd,
-        data: {'fid': uid, 'tagid': 0},
-      );
-    }).catchError((e) {
-      debugPrint(e.toString());
-      showCenterErrorToast('关注失败，${jsonDecode(e.response.data)['msg']}');
-    });
+    try {
+      await NetUtils.postWithCookieAndHeaderSet('${API.userRequestFollow}$uid');
+      await NetUtils.postWithCookieAndHeaderSet(API.userFollowAdd, data: {'fid': uid, 'tagid': 0});
+    } catch (e) {
+      debugPrint('Failed when folloe: $e');
+    }
   }
 
   static Future unFollow(int uid, {bool fromBlacklist = false}) async {
-    NetUtils.deleteWithCookieAndHeaderSet('${API.userRequestFollow}$uid').then((response) {
-      return NetUtils.postWithCookieAndHeaderSet(
-        API.userFollowDel,
-        data: {'fid': uid},
-      );
-    }).catchError((e) {
+    try {
+      await NetUtils.deleteWithCookieAndHeaderSet('${API.userRequestFollow}$uid');
+      await NetUtils.postWithCookieAndHeaderSet(API.userFollowAdd, data: {'fid': uid});
+    } catch (e) {
       debugPrint('Failed when unfollow $uid: $e');
-      if (!fromBlacklist) showCenterErrorToast('取消关注失败，${e.response.data['msg']}');
-    });
+      if (!fromBlacklist) showCenterErrorToast('取消关注失败');
+    }
   }
 
   static Future setSignature(content) async {
diff --git a/lib/constants/constants.dart b/lib/constants/constants.dart
index ce0d8187..a67c2fdb 100644
--- a/lib/constants/constants.dart
+++ b/lib/constants/constants.dart
@@ -8,8 +8,10 @@ import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:openjmu/constants/constants.dart';
 
 export 'package:dartx/dartx.dart';
+export 'package:dio/dio.dart' show Response;
 export 'package:ff_annotation_route/ff_annotation_route.dart' show FFRoute, PageRouteType;
 export 'package:oktoast/oktoast.dart' hide showToast;
+export 'package:pedantic/pedantic.dart';
 export 'package:url_launcher/url_launcher.dart';
 
 export 'package:openjmu/api/api.dart';
diff --git a/lib/constants/hive_boxes.dart b/lib/constants/hive_boxes.dart
index 77bdb5a3..f6a0b92f 100644
--- a/lib/constants/hive_boxes.dart
+++ b/lib/constants/hive_boxes.dart
@@ -49,7 +49,7 @@ class HiveBoxes {
     changelogBox = await Hive.openBox<ChangeLog>('openjmu_changelog');
   }
 
-  static void clearBoxes({context}) async {
+  static Future<void> clearBoxes({context}) async {
     bool confirm = true;
     if (context != null) {
       confirm = await ConfirmationBottomSheet.show(
@@ -72,7 +72,7 @@ class HiveBoxes {
       await settingsBox?.clear();
       await startWeekBox?.clear();
       debugPrint('Boxes cleared');
-      if (kReleaseMode) SystemNavigator.pop();
+      if (kReleaseMode) unawaited(SystemNavigator.pop());
     }
   }
 }
diff --git a/lib/controller/comment_controller.dart b/lib/controller/comment_controller.dart
index 7ba999de..f273b690 100755
--- a/lib/controller/comment_controller.dart
+++ b/lib/controller/comment_controller.dart
@@ -317,7 +317,7 @@ class CommentListInPostState extends State<CommentListInPost> with AutomaticKeep
         Routes.OPENJMU_ADD_COMMENT,
         arguments: {
           'post': widget.post,
-          'comment': _comments?.elementAt(index) ?? null,
+          'comment': _comments?.elementAt(index),
         },
       );
     }
diff --git a/lib/model/special_text.dart b/lib/model/special_text.dart
index 6562c678..b03dc9c7 100755
--- a/lib/model/special_text.dart
+++ b/lib/model/special_text.dart
@@ -110,7 +110,9 @@ class MentionText extends SpecialText {
   int getUidFromContent(content) {
     Iterable<Match> matches = mTagStartReg.allMatches(content);
     String result;
-    for (Match m in matches) result = m.group(0);
+    for (Match m in matches) {
+      result = m.group(0);
+    }
     return int.parse(result.substring(3, result.length - 1));
   }
 
@@ -286,8 +288,8 @@ class StackSpecialTextSpanBuilder extends SpecialTextSpanBuilder {
   final List<InlineSpan> suffixSpans;
 
   StackSpecialTextSpanBuilder({
-    this.builderType: BuilderType.extendedText,
-    this.widgetType: WidgetType.post,
+    this.builderType = BuilderType.extendedText,
+    this.widgetType = WidgetType.post,
     this.prefixSpans,
     this.suffixSpans,
   });
@@ -333,7 +335,7 @@ class StackSpecialTextSpanBuilder extends SpecialTextSpanBuilder {
           if (specialText != null) {
             if (textStack.length - specialText.startFlag.length >= 0) {
               textStack = textStack.substring(0, textStack.length - specialText.startFlag.length);
-              if (textStack.length > 0) {
+              if (textStack.isNotEmpty) {
                 inlineList.add(TextSpan(text: textStack, style: textStyle));
               }
             }
@@ -346,7 +348,7 @@ class StackSpecialTextSpanBuilder extends SpecialTextSpanBuilder {
           text: specialText.startFlag + specialText.getContent(),
           style: textStyle,
         ));
-      } else if (textStack.length > 0) {
+      } else if (textStack.isNotEmpty) {
         inlineList.add(TextSpan(text: textStack, style: textStyle));
       }
     } else {
diff --git a/lib/model/user.dart b/lib/model/user.dart
index adb23101..529936bf 100644
--- a/lib/model/user.dart
+++ b/lib/model/user.dart
@@ -34,7 +34,7 @@ class User {
       nickname: json['nickname'] ?? json['username'] ?? json['name'] ?? json['uid'].toString(),
       gender: json['gender'] ?? 0,
       topics: json['topics'] ?? 0,
-      latestTid: json['latest_tid'] ?? null,
+      latestTid: json['latest_tid'],
       fans: json['fans'] ?? 0,
       idols: json['idols'] ?? 0,
       isFollowing: json['is_following'] == 1,
diff --git a/lib/pages/chat/chat_app_message_page.dart b/lib/pages/chat/chat_app_message_page.dart
index c3485537..eb503948 100644
--- a/lib/pages/chat/chat_app_message_page.dart
+++ b/lib/pages/chat/chat_app_message_page.dart
@@ -223,7 +223,9 @@ class _ChatAppMessagePageState extends State<ChatAppMessagePage> {
       final content = jsonDecode(message.content);
       message.content = content['content'];
       if (mounted) setState(() {});
-    } catch (e) {}
+    } catch (e) {
+      return;
+    }
   }
 
   @override
diff --git a/lib/pages/chat/chat_person_page.dart b/lib/pages/chat/chat_person_page.dart
index df371d4f..ebe15069 100644
--- a/lib/pages/chat/chat_person_page.dart
+++ b/lib/pages/chat/chat_person_page.dart
@@ -291,8 +291,8 @@ class _ChatPersonPageState extends State<ChatPersonPage> {
     } else {
       if (MediaQuery.of(context).viewInsets.bottom != 0.0) {
         SystemChannels.textInput.invokeMethod('TextInput.hide').whenComplete(
-          () async {
-            Future.delayed(const Duration(milliseconds: 300), () {}).whenComplete(change);
+          () {
+            Future.delayed(300.milliseconds, () {}).whenComplete(change);
           },
         );
       } else {
diff --git a/lib/pages/home/add_button_page.dart b/lib/pages/home/add_button_page.dart
index 4c6d5d90..f26b6c7d 100755
--- a/lib/pages/home/add_button_page.dart
+++ b/lib/pages/home/add_button_page.dart
@@ -17,10 +17,10 @@ class _AddingButtonPageState extends State<AddingButtonPage> with TickerProvider
   final List<String> itemTitles = ['广场', '集市'];
   final List<Color> itemColors = [Colors.orange, Colors.indigoAccent];
   final List<Function> itemOnTap = [
-    (context) async {
+    (context) {
       navigatorState.pushNamed(Routes.OPENJMU_PUBLISH_POST);
     },
-    (context) async {
+    (context) {
       navigatorState.pushNamed(Routes.OPENJMU_PUBLISH_TEAM_POST);
     },
   ];
diff --git a/lib/pages/home/app_center_page.dart b/lib/pages/home/app_center_page.dart
index a7c8f88b..bd6b4744 100644
--- a/lib/pages/home/app_center_page.dart
+++ b/lib/pages/home/app_center_page.dart
@@ -56,7 +56,9 @@ class AppCenterPage extends StatelessWidget {
           content: '是否使用浏览器打开该应用?',
           showConfirm: true,
         );
-        if (confirm) launch(webApp.replacedUrl, forceSafariVC: false);
+        if (confirm) {
+          unawaited(launch(webApp.replacedUrl, forceSafariVC: false));
+        }
       },
     );
   }
diff --git a/lib/pages/home/course_schedule_page.dart b/lib/pages/home/course_schedule_page.dart
index eee87127..473b7e5c 100755
--- a/lib/pages/home/course_schedule_page.dart
+++ b/lib/pages/home/course_schedule_page.dart
@@ -80,12 +80,13 @@ class CourseSchedulePageState extends State<CourseSchedulePage> with AutomaticKe
   void scrollToWeek(int week) {
     currentWeek = week;
     if (mounted) setState(() {});
-    if (weekScrollController?.hasClients ?? false)
+    if (weekScrollController?.hasClients ?? false) {
       weekScrollController.animateTo(
         math.max(0, (week - 0.5) * suSetWidth(weekSize) - Screens.width / 2),
         duration: const Duration(milliseconds: 300),
         curve: Curves.ease,
       );
+    }
   }
 
   void showRemarkDetail(context) {
diff --git a/lib/pages/home/post_square_list_page.dart b/lib/pages/home/post_square_list_page.dart
index 0c61b893..99b705c2 100755
--- a/lib/pages/home/post_square_list_page.dart
+++ b/lib/pages/home/post_square_list_page.dart
@@ -114,7 +114,7 @@ class PostSquareListPageState extends State<PostSquareListPage>
             [PermissionGroup.camera],
           );
           if (permissions[PermissionGroup.camera] == PermissionStatus.granted) {
-            navigatorState.pushNamed(Routes.OPENJMU_SCAN_QRCODE);
+            unawaited(navigatorState.pushNamed(Routes.OPENJMU_SCAN_QRCODE));
           }
         },
       );
diff --git a/lib/pages/home/scan_qrcode_page.dart b/lib/pages/home/scan_qrcode_page.dart
index 1b51cbae..1fd495f4 100755
--- a/lib/pages/home/scan_qrcode_page.dart
+++ b/lib/pages/home/scan_qrcode_page.dart
@@ -17,15 +17,14 @@ class _ScanQrCodePageState extends State<ScanQrCodePage> {
   Future<void> onScan(context, String data) async {
     if (data == null) {
       showCenterErrorToast('没有识别到二维码~换一张试试');
-      return;
     }
     if (API.urlReg.stringMatch(data) != null) {
-      API.launchWeb(url: '$data');
+      unawaited(API.launchWeb(url: '$data'));
     } else if (API.schemeUserPage.stringMatch(data) != null) {
-      Navigator.of(context).pushReplacementNamed(
+      unawaited(Navigator.of(context).pushReplacementNamed(
         Routes.OPENJMU_USER,
         arguments: {'uid': int.parse(data.substring(API.schemeUserPage.pattern.length - 2))},
-      );
+      ));
     } else {
       final needCopy = await ConfirmationDialog.show(
         context,
@@ -35,7 +34,9 @@ class _ScanQrCodePageState extends State<ScanQrCodePage> {
         confirmLabel: '复制',
         cancelLabel: '返回',
       );
-      if (needCopy) Clipboard.setData(ClipboardData(text: '$data'));
+      if (needCopy) {
+        unawaited(Clipboard.setData(ClipboardData(text: '$data')));
+      }
       _key.currentState.startScan();
     }
   }
diff --git a/lib/pages/login_page.dart b/lib/pages/login_page.dart
index 785a655c..fb4f70da 100755
--- a/lib/pages/login_page.dart
+++ b/lib/pages/login_page.dart
@@ -63,11 +63,11 @@ class LoginPageState extends State<LoginPage> with SingleTickerProviderStateMixi
   void usernameListener() {
     _username = _usernameController.text;
     if (this.mounted) {
-      if (_usernameController.text.length > 0 && !_usernameCanClear) {
+      if (_usernameController.text.isNotEmpty && !_usernameCanClear) {
         setState(() {
           _usernameCanClear = true;
         });
-      } else if (_usernameController.text.length == 0 && _usernameCanClear) {
+      } else if (_usernameController.text.isEmpty && _usernameCanClear) {
         setState(() {
           _usernameCanClear = false;
         });
@@ -476,11 +476,11 @@ class LoginPageState extends State<LoginPage> with SingleTickerProviderStateMixi
       showConfirm: true,
     );
     if (confirm) {
-      API.launchWeb(
+      unawaited(API.launchWeb(
         url: 'https://net.jmu.edu.cn/info/1309/2476.htm',
         title: '网页链接',
         withCookie: false,
-      );
+      ));
     }
   }
 
diff --git a/lib/pages/main_page.dart b/lib/pages/main_page.dart
index 426557d7..1830260d 100755
--- a/lib/pages/main_page.dart
+++ b/lib/pages/main_page.dart
@@ -83,7 +83,7 @@ class MainPageState extends State<MainPage> with AutomaticKeepAliveClientMixin {
     super.dispose();
   }
 
-  void initPushService() async {
+  void initPushService() {
     try {
       final data = <String, dynamic>{
         'token': DeviceUtils.devicePushToken,
diff --git a/lib/pages/notification/notification_entry_page.dart b/lib/pages/notification/notification_entry_page.dart
index a3c0f701..435432c4 100644
--- a/lib/pages/notification/notification_entry_page.dart
+++ b/lib/pages/notification/notification_entry_page.dart
@@ -28,7 +28,7 @@ class _NotificationEntryPageState extends State<NotificationEntryPage>
         currentContext,
         listen: false,
       ).notifications,
-      'onTap': (context) async {
+      'onTap': (context) {
         navigatorState.pushNamed(Routes.OPENJMU_NOTIFICATIONS);
       },
     },
@@ -39,7 +39,7 @@ class _NotificationEntryPageState extends State<NotificationEntryPage>
         currentContext,
         listen: false,
       ).teamNotifications,
-      'onTap': (context) async {
+      'onTap': (context) {
         navigatorState.pushNamed(Routes.OPENJMU_TEAM_NOTIFICATIONS);
       },
     },
diff --git a/lib/pages/post/post_detail_page.dart b/lib/pages/post/post_detail_page.dart
index 661fc329..4d14d2b1 100755
--- a/lib/pages/post/post_detail_page.dart
+++ b/lib/pages/post/post_detail_page.dart
@@ -190,7 +190,7 @@ class PostDetailPageState extends State<PostDetailPage> {
         onPressed: () => postExtraActions(context),
       );
 
-  void confirmDelete(context) async {
+  Future<void> confirmDelete(context) async {
     final confirm = await ConfirmationDialog.show(
       context,
       title: '删除动态',
@@ -205,14 +205,15 @@ class PostDetailPageState extends State<PostDetailPage> {
         text: '正在删除动态',
         isGlobal: false,
       );
-      PostAPI.deletePost(widget.post.id).then((response) {
+      try {
+        await PostAPI.deletePost(widget.post.id);
         _loadingDialogController.changeState('success', '动态删除成功');
         Instances.eventBus.fire(PostDeletedEvent(widget.post.id, widget.fromPage, widget.index));
-      }).catchError((e) {
+      } catch (e) {
         debugPrint(e.toString());
         debugPrint(e.response?.toString());
         _loadingDialogController.changeState('failed', '动态删除失败');
-      });
+      }
     }
   }
 
@@ -254,7 +255,7 @@ class PostDetailPageState extends State<PostDetailPage> {
       final provider = Provider.of<ReportRecordsProvider>(context, listen: false);
       final canReport = await provider.addRecord(widget.post.id);
       if (canReport) {
-        PostAPI.reportPost(widget.post);
+        unawaited(PostAPI.reportPost(widget.post));
         showToast('举报成功');
         navigatorState.pop();
       }
diff --git a/lib/pages/post/publish_post_page.dart b/lib/pages/post/publish_post_page.dart
index a99f64d5..08c077ec 100755
--- a/lib/pages/post/publish_post_page.dart
+++ b/lib/pages/post/publish_post_page.dart
@@ -62,7 +62,7 @@ class PublishPostPageState extends State<PublishPostPage> {
   void addTopic() {
     final currentPosition = _textEditingController.selection.baseOffset;
     String result;
-    if (_textEditingController.text.length > 0) {
+    if (_textEditingController.text.isNotEmpty) {
       final leftText = _textEditingController.text.substring(0, currentPosition);
       final rightText = _textEditingController.text
           .substring(currentPosition, _textEditingController.text.length);
@@ -415,7 +415,7 @@ class PublishPostPageState extends State<PublishPostPage> {
     }
   }
 
-  void post(context) async {
+  Future<void> post(context) async {
     final content = _textEditingController.text;
     if (content?.trim()?.isEmpty ?? true) {
       showCenterToast('内容不能为空');
@@ -456,12 +456,12 @@ class PublishPostPageState extends State<PublishPostPage> {
         LoadingDialog.show(
           context,
           controller: _dialogController,
-          text: assets.length > 0 ? '正在上传图片 (1/${assets.length})' : '正在发布动态...',
+          text: assets.isNotEmpty ? '正在上传图片 (1/${assets.length})' : '正在发布动态...',
         );
         Map<String, dynamic> data = {};
         data['category'] = 'text';
         data['content'] = Uri.encodeFull(content);
-        if (assets.length > 0) {
+        if (assets.isNotEmpty) {
           try {
             if (query == null) query = List(assets.length);
             _imageIdList = List(assets.length);
@@ -470,8 +470,8 @@ class PublishPostPageState extends State<PublishPostPage> {
               final _form = await createForm(imageData);
               query[i] = getImageRequest(_form, i);
             }
-            _postImagesQuery().then((responses) {
-              final rs = responses as List;
+            try {
+              final List rs = await _postImagesQuery();
               if (rs != null && rs.length == assets.length && !rs.contains(null)) {
                 final extraId = _imageIdList.toString();
                 data['extra_id'] = extraId.substring(1, extraId.length - 1);
@@ -482,13 +482,13 @@ class PublishPostPageState extends State<PublishPostPage> {
                 isLoading = false;
                 if (mounted) setState(() {});
               }
-            }).catchError((e) {
+            } catch (e) {
               query = [];
               _dialogController.changeState('failed', '图片上传失败');
               isLoading = false;
               if (mounted) setState(() {});
               debugPrint(e.toString());
-            });
+            }
           } catch (exception) {
             query = [];
             debugPrint(exception.toString());
@@ -544,8 +544,8 @@ class PublishPostPageState extends State<PublishPostPage> {
         if (mounted) setState(() {});
       });
 
-  Future _postContent(content) async {
-    if (assets.length > 0) {
+  void _postContent(content) {
+    if (assets.isNotEmpty) {
       _dialogController.updateText('正在发布动态...');
     }
     NetUtils.postWithCookieAndHeaderSet(
diff --git a/lib/pages/post/publish_team_post_page.dart b/lib/pages/post/publish_team_post_page.dart
index 64971c6c..da00f44d 100644
--- a/lib/pages/post/publish_team_post_page.dart
+++ b/lib/pages/post/publish_team_post_page.dart
@@ -66,7 +66,7 @@ class PublishTeamPostPageState extends State<PublishTeamPostPage> {
   void addTopic() {
     final currentPosition = _textEditingController.selection.baseOffset;
     String result;
-    if (_textEditingController.text.length > 0) {
+    if (_textEditingController.text.isNotEmpty) {
       final leftText = _textEditingController.text.substring(0, currentPosition);
       final rightText = _textEditingController.text
           .substring(currentPosition, _textEditingController.text.length);
@@ -473,10 +473,10 @@ class PublishTeamPostPageState extends State<PublishTeamPostPage> {
         LoadingDialog.show(
           context,
           controller: _dialogController,
-          text: assets.length > 0 ? '正在上传图片 (1/${assets.length})' : '正在发布动态...',
+          text: assets.isNotEmpty ? '正在上传图片 (1/${assets.length})' : '正在发布动态...',
         );
 
-        if (assets.length > 0) {
+        if (assets.isNotEmpty) {
           try {
             if (query == null) query = List(assets.length);
             _imageIdList = List(assets.length);
@@ -485,8 +485,8 @@ class PublishTeamPostPageState extends State<PublishTeamPostPage> {
               final _form = await createForm(imageData);
               query[i] = getImageRequest(_form, i);
             }
-            _postImagesQuery().then((responses) {
-              final rs = responses as List;
+            try {
+              final List rs = await _postImagesQuery();
               if (rs != null && rs.length == assets.length && !rs.contains(null)) {
                 _postContent();
               } else {
@@ -495,13 +495,13 @@ class PublishTeamPostPageState extends State<PublishTeamPostPage> {
                 isLoading = false;
                 if (mounted) setState(() {});
               }
-            }).catchError((e) {
+            } catch (e) {
               query = [];
               _dialogController.changeState('failed', '图片上传失败');
               isLoading = false;
               if (mounted) setState(() {});
               debugPrint(e.toString());
-            });
+            }
           } catch (exception) {
             query = [];
             debugPrint(exception.toString());
@@ -555,12 +555,12 @@ class PublishTeamPostPageState extends State<PublishTeamPostPage> {
         if (mounted) setState(() {});
       });
 
-  Future _postContent() async {
+  void _postContent() {
     String content = _textEditingController.text;
-    if (imagesLength != 0 && content == null || content.trim().length == 0) {
+    if (imagesLength != 0 && content == null || content.trim().isEmpty) {
       content = '分享图片~';
     }
-    if (assets.length > 0) {
+    if (assets.isNotEmpty) {
       _dialogController.updateText('正在发布动态...');
     }
     TeamPostAPI.publishPost(
diff --git a/lib/pages/post/team_post_detail_page.dart b/lib/pages/post/team_post_detail_page.dart
index 874f16f4..6c6ad732 100644
--- a/lib/pages/post/team_post_detail_page.dart
+++ b/lib/pages/post/team_post_detail_page.dart
@@ -80,18 +80,20 @@ class TeamPostDetailPageState extends State<TeamPostDetailPage> {
     initialLoad();
 
     _textEditingController.addListener(() {
-      final _canSend = _textEditingController.text.length > 0;
-      if (mounted && canSend != _canSend)
+      final _canSend = _textEditingController.text.isNotEmpty;
+      if (mounted && canSend != _canSend) {
         setState(() {
           canSend = _canSend;
         });
+      }
     });
 
     _focusNode.addListener(() {
-      if (mounted && _focusNode.hasFocus)
+      if (mounted && _focusNode.hasFocus) {
         setState(() {
           showExtendedPad = false;
         });
+      }
     });
 
     Instances.eventBus
@@ -378,7 +380,7 @@ class TeamPostDetailPageState extends State<TeamPostDetailPage> {
     await Future.delayed(const Duration(milliseconds: 100));
     final currentPosition = _textEditingController.selection.baseOffset;
     String result;
-    if (_textEditingController.text.length > 0) {
+    if (_textEditingController.text.isNotEmpty) {
       final leftText = _textEditingController.text.substring(0, currentPosition);
       final rightText = _textEditingController.text
           .substring(currentPosition, _textEditingController.text.length);
diff --git a/lib/pages/search_page.dart b/lib/pages/search_page.dart
index ca34de41..105d1b4a 100755
--- a/lib/pages/search_page.dart
+++ b/lib/pages/search_page.dart
@@ -56,7 +56,7 @@ class SearchPageState extends State<SearchPage> with AutomaticKeepAliveClientMix
   bool get wantKeepAlive => true;
 
   void canClearListener() {
-    _canClear = _controller.text.length > 0;
+    _canClear = _controller.text.isNotEmpty;
     if (mounted) setState(() {});
   }
 
@@ -81,7 +81,7 @@ class SearchPageState extends State<SearchPage> with AutomaticKeepAliveClientMix
 
   Future getPosts(String searchQuery) async {
     bool loadMore = false;
-    if (postList != null && postList.length > 0) {
+    if (postList != null && postList.isNotEmpty) {
       loadMore = true;
     }
     await PostAPI.getPostList(
@@ -92,7 +92,7 @@ class SearchPageState extends State<SearchPage> with AutomaticKeepAliveClientMix
       additionAttrs: {'words': searchQuery},
     ).then((response) {
       List _ps = response.data['topics'];
-      if (_ps.length == 0) _canLoadMore = false;
+      if (_ps.isEmpty) _canLoadMore = false;
       _ps.forEach((post) {
         Post p = Post.fromJson(post['topic']);
         if (postList == null) postList = [];
diff --git a/lib/pages/settings/about_page.dart b/lib/pages/settings/about_page.dart
index 0f1766d2..6021ee60 100755
--- a/lib/pages/settings/about_page.dart
+++ b/lib/pages/settings/about_page.dart
@@ -77,7 +77,7 @@ class AboutPage extends StatelessWidget {
       ),
     );
     if (copy) {
-      Clipboard.setData(ClipboardData(text: info));
+      unawaited(Clipboard.setData(ClipboardData(text: info)));
       showToast('已复制到剪贴板');
     }
   }
diff --git a/lib/pages/splash_page.dart b/lib/pages/splash_page.dart
index 37c54e9f..b7838b9f 100755
--- a/lib/pages/splash_page.dart
+++ b/lib/pages/splash_page.dart
@@ -124,7 +124,7 @@ class SplashState extends State<SplashPage> {
     if (mounted) setState(() {});
   }
 
-  Future navigate({bool forceToLogin = false}) async {
+  void navigate({bool forceToLogin = false}) {
     try {
       navigatorState.pushAndRemoveUntil(
         PageRouteBuilder(
diff --git a/lib/pages/user/backpack_page.dart b/lib/pages/user/backpack_page.dart
index cd803716..f56c4408 100755
--- a/lib/pages/user/backpack_page.dart
+++ b/lib/pages/user/backpack_page.dart
@@ -91,9 +91,9 @@ class _BackpackPageState extends State<BackpackPage> {
     getBackpackItem();
   }
 
-  Future getBackpackItem() async {
+  Future<void> getBackpackItem() async {
     try {
-      Map<String, dynamic> types = (await NetUtils.getWithHeaderSet(
+      final Map<String, dynamic> types = (await NetUtils.getWithHeaderSet(
         API.backPackItemType(),
         headers: _header,
       ))
@@ -104,7 +104,7 @@ class _BackpackPageState extends State<BackpackPage> {
         _itemTypes['${item.type}'] = item;
       }
 
-      Future.wait(<Future>[
+      await Future.wait(<Future>[
         NetUtils.getWithHeaderSet(
           API.backPackMyItemList(),
           headers: _header,
@@ -121,7 +121,7 @@ class _BackpackPageState extends State<BackpackPage> {
           API.backPackReceiveList(),
           headers: _header,
         ).then((response) {
-//                        print(response);
+//          print(response);
         }),
       ]).then((responses) {
         setState(() {
diff --git a/lib/pages/user/user_page.dart b/lib/pages/user/user_page.dart
index 99d0ae71..27c5c83b 100755
--- a/lib/pages/user/user_page.dart
+++ b/lib/pages/user/user_page.dart
@@ -114,7 +114,7 @@ class _UserPageState extends State<UserPage>
     }
   }
 
-  Future<Null> _fetchUserInformation(uid) async {
+  Future<void> _fetchUserInformation(uid) async {
     if (uid == UserAPI.currentUser.uid) {
       _user = UserAPI.currentUser;
     } else {
@@ -122,7 +122,7 @@ class _UserPageState extends State<UserPage>
       _user = UserInfo.fromJson(user);
     }
 
-    Future.wait(<Future>[
+    await Future.wait(<Future>[
       UserAPI.getLevel(uid).then((response) {
         userLevel = int.parse(response.data['score']['levelinfo']['level'].toString());
       }),
@@ -135,24 +135,25 @@ class _UserPageState extends State<UserPage>
         _tags = _userTags;
       }),
       _getCount(uid),
-    ]).then((whatever) {
-      if (mounted) {
-        setState(() {
-          isLoading = false;
-          refreshing = false;
-        });
-      }
-    });
+    ]);
+
+    if (mounted) {
+      setState(() {
+        isLoading = false;
+        refreshing = false;
+      });
+    }
   }
 
   Future<Null> _getCount(id) async {
     Map data = (await UserAPI.getFansAndFollowingsCount(id)).data;
-    if (this.mounted)
+    if (this.mounted) {
       setState(() {
         _user.isFollowing = data['is_following'] == 1;
         _fansCount = data['fans'].toString();
         _idolsCount = data['idols'].toString();
       });
+    }
   }
 
   Widget avatar(context, double width) {
@@ -199,6 +200,9 @@ class _UserPageState extends State<UserPage>
                 UserAPI.follow(widget.uid).then((response) {
                   _user.isFollowing = true;
                   if (mounted) setState(() {});
+                }).catchError((e) {
+                  debugPrint('Failed when follow: $e');
+                  showCenterErrorToast('关注失败');
                 });
               }
             }
@@ -387,7 +391,7 @@ class _UserPageState extends State<UserPage>
             ),
           ],
         ),
-        _tags?.length != 0
+        _tags?.isNotEmpty ?? false
             ? SingleChildScrollView(
                 scrollDirection: Axis.horizontal,
                 child: Row(
@@ -468,7 +472,7 @@ class _UserPageState extends State<UserPage>
     );
   }
 
-  void avatarExtraActions(context) async {
+  void avatarExtraActions(context) {
     ConfirmationBottomSheet.show(
       context,
       children: <Widget>[
@@ -495,7 +499,7 @@ class _UserPageState extends State<UserPage>
         ConfirmationBottomSheetAction(
           icon: Icon(Icons.photo_library),
           text: '更换头像',
-          onTap: () async {
+          onTap: () {
             Navigator.of(context).pop();
             navigatorState.pushNamed(Routes.OPENJMU_IMAGE_CROP).then((result) {
               if (result != null && result) {
@@ -782,8 +786,10 @@ class _UserListState extends State<UserListPage> {
     int total = int.parse(response.data['total'].toString());
     if (_users.length + data.length < total) canLoadMore = true;
     List users = [];
-    for (int i = 0; i < data.length; i++) users.add(data[i]);
-    if (mounted)
+    for (int i = 0; i < data.length; i++) {
+      users.add(data[i]);
+    }
+    if (mounted) {
       setState(() {
         if (isMore) {
           List _u = _users;
@@ -794,6 +800,7 @@ class _UserListState extends State<UserListPage> {
         }
         isLoading = false;
       });
+    }
   }
 
   Widget renderRow(context, i) {
@@ -912,7 +919,7 @@ class _UserListState extends State<UserListPage> {
           FixedAppBar(title: Text('$_type列表')),
           Expanded(
             child: !isLoading
-                ? _users.length != 0
+                ? _users?.isNotEmpty ?? false
                     ? ListView.builder(
                         padding: EdgeInsets.zero,
                         itemCount: (_users.length / 2).ceil(),
diff --git a/lib/providers/courses_provider.dart b/lib/providers/courses_provider.dart
index ac2ed307..f5970d99 100644
--- a/lib/providers/courses_provider.dart
+++ b/lib/providers/courses_provider.dart
@@ -119,6 +119,7 @@ class CoursesProvider extends ChangeNotifier {
     if (showWeek) {
       showWeek = false;
       if (Instances.appsPageStateKey.currentState?.mounted ?? false) {
+        // ignore: invalid_use_of_protected_member
         Instances.appsPageStateKey.currentState?.setState(() {});
       }
     }
@@ -133,6 +134,7 @@ class CoursesProvider extends ChangeNotifier {
       Instances.courseSchedulePageStateKey.currentState?.updateScrollController();
       notifyListeners();
 
+      // ignore: invalid_use_of_protected_member
       Instances.courseSchedulePageStateKey.currentState?.setState(() {});
     } catch (e) {
       debugPrint('Error when updating course: $e');
diff --git a/lib/providers/date_provider.dart b/lib/providers/date_provider.dart
index a78f68ba..f25d6856 100644
--- a/lib/providers/date_provider.dart
+++ b/lib/providers/date_provider.dart
@@ -66,9 +66,9 @@ class DateProvider extends ChangeNotifier {
         _day = DateTime.parse(jsonDecode(result)['start']);
       }
       if (_startDate == null) {
-        updateStartDate(_day);
+        unawaited(updateStartDate(_day));
       } else {
-        if (_startDate != _day) updateStartDate(_day);
+        if (_startDate != _day) unawaited(updateStartDate(_day));
       }
 
       final _d = _startDate.difference(now).inDays;
diff --git a/lib/providers/themes_provider.dart b/lib/providers/themes_provider.dart
index 877cdc7b..edce006b 100644
--- a/lib/providers/themes_provider.dart
+++ b/lib/providers/themes_provider.dart
@@ -54,7 +54,7 @@ class ThemesProvider with ChangeNotifier {
     _platformBrightness = HiveFieldUtils.getBrightnessPlatform();
   }
 
-  Future<void> resetTheme() async {
+  void resetTheme() {
     HiveFieldUtils.setColorTheme(0);
     HiveFieldUtils.setAMOLEDDark(false);
     HiveFieldUtils.setBrightnessDark(false);
diff --git a/lib/providers/webapps_provider.dart b/lib/providers/webapps_provider.dart
index 43eb9634..9ebc260b 100644
--- a/lib/providers/webapps_provider.dart
+++ b/lib/providers/webapps_provider.dart
@@ -20,7 +20,7 @@ class WebAppsProvider extends ChangeNotifier {
 
   Future getAppList() async => NetUtils.getWithCookieSet(API.webAppLists);
 
-  void initApps() async {
+  void initApps() {
     _appCategoriesList = <String, Set<WebApp>>{
       for (final key in categories.keys) key: <WebApp>{},
     };
diff --git a/lib/utils/channel_utils.dart b/lib/utils/channel_utils.dart
index 0f79737b..95c0e31a 100755
--- a/lib/utils/channel_utils.dart
+++ b/lib/utils/channel_utils.dart
@@ -4,9 +4,9 @@ import 'package:flutter/services.dart';
 class ChannelUtils {
   const ChannelUtils._();
 
-  static const _pmc_flagSecure = const MethodChannel('cn.edu.jmu.openjmu/setFlagSecure');
-  static const _pmc_schemeLauncher = const MethodChannel('cn.edu.jmu.openjmu/schemeLauncher');
-  static const _pmc_iOSPushToken = const MethodChannel('cn.edu.jmu.openjmu/iOSPushToken');
+  static const _pmc_flagSecure = MethodChannel('cn.edu.jmu.openjmu/setFlagSecure');
+  static const _pmc_schemeLauncher = MethodChannel('cn.edu.jmu.openjmu/schemeLauncher');
+  static const _pmc_iOSPushToken = MethodChannel('cn.edu.jmu.openjmu/iOSPushToken');
 
   static Future<Null> setFlagSecure(bool secure) async {
     try {
diff --git a/lib/utils/data_utils.dart b/lib/utils/data_utils.dart
index 7cff350b..1952f8ff 100755
--- a/lib/utils/data_utils.dart
+++ b/lib/utils/data_utils.dart
@@ -60,7 +60,7 @@ class DataUtils {
     }
   }
 
-  static Future<void> logout() async {
+  static void logout() {
     UserAPI.blacklist?.clear();
     MessageUtils.sendLogout();
     NetUtils.postWithCookieSet(API.logout).whenComplete(() {
@@ -84,7 +84,7 @@ class DataUtils {
 
   static String recoverWorkId() => settingsBox.get(spUserWorkId);
 
-  static Future recoverLoginInfo() async {
+  static void recoverLoginInfo() async {
     final info = getSpTicket();
     UserAPI.currentUser.ticket = info['ticket'];
   }
diff --git a/lib/utils/message_utils.dart b/lib/utils/message_utils.dart
index 45b26bb4..90811ed1 100755
--- a/lib/utils/message_utils.dart
+++ b/lib/utils/message_utils.dart
@@ -239,7 +239,7 @@ class MessageUtils {
     try {
       final package = packageBuilder(
         Messages.messageCommands[command],
-        content?.requestBody() ?? null,
+        content?.requestBody(),
       );
       messageSocket.add(package);
       debugPrint('\nSending $command: $package');
@@ -357,7 +357,9 @@ class MessageUtils {
     // Fire [MessageReceivedEvent].
     Instances.eventBus.fire(event);
     // Notify each listener with event.
-    for (final listener in messageListeners) listener(event);
+    for (final listener in messageListeners) {
+      listener(event);
+    }
   }
 
   static decodeMultiOfflineMessage(Packet packet) {
@@ -416,13 +418,17 @@ class UintConverter {
     final bytes = value.toUtf8();
     // String package needs to add length before content.
     addWrapper(UintWrapper(bytes.length, 16));
-    for (final byte in bytes) add(byte, 8);
+    for (final byte in bytes) {
+      add(byte, 8);
+    }
   }
 
   Uint8List asUint8List() {
     int size = 0;
     int offset = 0;
-    for (final number in numbers) size += number.radix ~/ 8;
+    for (final number in numbers) {
+      size += number.radix ~/ 8;
+    }
     final ByteBuffer buffer = Uint8List(size).buffer;
     final ByteData data = ByteData.view(buffer);
 
diff --git a/lib/utils/net_utils.dart b/lib/utils/net_utils.dart
index 46b65eac..9230a51b 100755
--- a/lib/utils/net_utils.dart
+++ b/lib/utils/net_utils.dart
@@ -97,12 +97,12 @@ class NetUtils {
         ),
       );
 
-  static Future<Response> getWithCookieSet(
+  static Future<Response<T>> getWithCookieSet<T>(
     String url, {
     data,
     cookies,
   }) async =>
-      await dio.get(
+      await dio.get<T>(
         url,
         queryParameters: data,
         options: Options(
@@ -110,13 +110,13 @@ class NetUtils {
         ),
       );
 
-  static Future<Response> getWithCookieAndHeaderSet(
+  static Future<Response<T>> getWithCookieAndHeaderSet<T>(
     String url, {
     data,
     cookies,
     headers,
   }) async =>
-      await dio.get(
+      await dio.get<T>(
         url,
         queryParameters: data,
         options: Options(
@@ -125,9 +125,12 @@ class NetUtils {
         ),
       );
 
-  static Future<Response> post(String url, {data}) async => await dio.post(url, data: data);
+  static Future<Response<T>> post<T>(String url, {data}) async => await dio.post<T>(
+        url,
+        data: data,
+      );
 
-  static Future<Response> postWithCookieSet(String url, {data}) async => await dio.post(
+  static Future<Response<T>> postWithCookieSet<T>(String url, {data}) async => await dio.post<T>(
         url,
         data: data,
         options: Options(
@@ -135,13 +138,13 @@ class NetUtils {
         ),
       );
 
-  static Future<Response> postWithCookieAndHeaderSet(
+  static Future<Response<T>> postWithCookieAndHeaderSet<T>(
     String url, {
     cookies,
     headers,
     data,
   }) async =>
-      await dio.post(
+      await dio.post<T>(
         url,
         data: data,
         options: Options(
@@ -150,12 +153,12 @@ class NetUtils {
         ),
       );
 
-  static Future<Response> deleteWithCookieAndHeaderSet(
+  static Future<Response<T>> deleteWithCookieAndHeaderSet<T>(
     String url, {
     data,
     headers,
   }) async =>
-      await dio.delete(
+      await dio.delete<T>(
         url,
         data: data,
         options: Options(
diff --git a/lib/utils/ota_utils.dart b/lib/utils/ota_utils.dart
index ee90dde3..9c12e8ed 100755
--- a/lib/utils/ota_utils.dart
+++ b/lib/utils/ota_utils.dart
@@ -28,8 +28,8 @@ class OTAUtils {
     _packageInfo = await PackageInfo.fromPlatform();
   }
 
-  static Future<void> checkUpdate({bool fromHome = false}) async {
-    NetUtils.get(API.checkUpdate).then((response) async {
+  static void checkUpdate({bool fromHome = false}) {
+    NetUtils.get(API.checkUpdate).then((response) {
       final data = jsonDecode(response.data);
       updateChangelog(data['changelog']);
       final _currentBuild = buildNumber;
@@ -63,13 +63,13 @@ class OTAUtils {
       LaunchReview.launch(iOSAppId: '1459832676');
     } else {
       if (await canLaunch('coolmarket://apk/$packageName')) {
-        launch('coolmarket://apk/$packageName');
+        unawaited(launch('coolmarket://apk/$packageName'));
       } else {
-        launch(
+        unawaited(launch(
           'https://www.coolapk.com/apk/$packageName',
           forceSafariVC: false,
           forceWebView: false,
-        );
+        ));
       }
     }
   }
@@ -197,11 +197,11 @@ class OTAUtils {
     final box = HiveBoxes.changelogBox;
     final List<ChangeLog> logs = data.map((log) => ChangeLog.fromJson(log)).toList();
     if (box.values == null) {
-      box.addAll(logs);
+      await box.addAll(logs);
     } else {
       if (box.values.toString() != logs.toString()) {
         await box.clear();
-        box.addAll(logs);
+        await box.addAll(logs);
       }
     }
   }
diff --git a/lib/utils/toast_utils.dart b/lib/utils/toast_utils.dart
index b7c4b7f1..edc02d96 100644
--- a/lib/utils/toast_utils.dart
+++ b/lib/utils/toast_utils.dart
@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+// ignore: library_prefixes
 import 'package:oktoast/oktoast.dart' as OKToast;
 
 void showToast(String text) {
diff --git a/lib/widgets/cards/post_card.dart b/lib/widgets/cards/post_card.dart
index 27259976..ddf4f6e2 100755
--- a/lib/widgets/cards/post_card.dart
+++ b/lib/widgets/cards/post_card.dart
@@ -534,14 +534,15 @@ class _PostCardState extends State<PostCard> {
         text: '正在删除动态',
         isGlobal: false,
       );
-      PostAPI.deletePost(widget.post.id).then((response) {
+      try {
+        await PostAPI.deletePost(widget.post.id);
         _loadingDialogController.changeState('success', '动态删除成功');
         Instances.eventBus.fire(PostDeletedEvent(widget.post.id, widget.fromPage, widget.index));
-      }).catchError((e) {
+      } catch (e) {
         debugPrint(e.toString());
         debugPrint(e.response?.toString());
         _loadingDialogController.changeState('failed', '动态删除失败');
-      });
+      }
     }
   }
 
@@ -579,7 +580,7 @@ class _PostCardState extends State<PostCard> {
       final provider = Provider.of<ReportRecordsProvider>(context, listen: false);
       final canReport = await provider.addRecord(widget.post.id);
       if (canReport) {
-        PostAPI.reportPost(widget.post);
+        unawaited(PostAPI.reportPost(widget.post));
         showToast('举报成功');
       }
     }
diff --git a/lib/widgets/cards/team_comment_preview_card.dart b/lib/widgets/cards/team_comment_preview_card.dart
index 20a8bc40..6329121c 100644
--- a/lib/widgets/cards/team_comment_preview_card.dart
+++ b/lib/widgets/cards/team_comment_preview_card.dart
@@ -207,11 +207,9 @@ class TeamCommentPreviewCard extends StatelessWidget {
             shrinkWrap: true,
             itemCount: post.replyInfo.length + (post.replyInfo.length != post.repliesCount ? 1 : 0),
             itemBuilder: (_, index) {
-              if (index == post.replyInfo.length)
+              if (index == post.replyInfo.length) {
                 return Container(
-                  margin: EdgeInsets.only(
-                    top: suSetHeight(12.0),
-                  ),
+                  margin: EdgeInsets.only(top: suSetHeight(12.0)),
                   child: Row(
                     mainAxisAlignment: MainAxisAlignment.center,
                     children: <Widget>[
@@ -234,11 +232,10 @@ class TeamCommentPreviewCard extends StatelessWidget {
                     ],
                   ),
                 );
+              }
               final _post = post.replyInfo[index];
               return Padding(
-                padding: EdgeInsets.symmetric(
-                  vertical: suSetHeight(4.0),
-                ),
+                padding: EdgeInsets.symmetric(vertical: suSetHeight(4.0)),
                 child: Row(
                   children: <Widget>[
                     Expanded(
@@ -248,9 +245,7 @@ class TeamCommentPreviewCard extends StatelessWidget {
                           prefixSpans: <InlineSpan>[
                             TextSpan(
                               text: '@${_post['user']['nickname']}',
-                              style: TextStyle(
-                                color: Colors.blue,
-                              ),
+                              style: TextStyle(color: Colors.blue),
                               recognizer: TapGestureRecognizer()
                                 ..onTap = () {
                                   navigatorState.pushNamed(
@@ -286,9 +281,7 @@ class TeamCommentPreviewCard extends StatelessWidget {
                               ),
                             TextSpan(
                               text: ': ',
-                              style: TextStyle(
-                                color: Colors.blue,
-                              ),
+                              style: TextStyle(color: Colors.blue),
                             ),
                           ],
                         ),
diff --git a/lib/widgets/cards/team_post_preview_card.dart b/lib/widgets/cards/team_post_preview_card.dart
index a7332926..99db51b4 100644
--- a/lib/widgets/cards/team_post_preview_card.dart
+++ b/lib/widgets/cards/team_post_preview_card.dart
@@ -80,7 +80,7 @@ class TeamPostPreviewCard extends StatelessWidget {
       showConfirm: true,
     );
     if (confirm) {
-      TeamPostAPI.reportPost(post);
+      unawaited(TeamPostAPI.reportPost(post));
       showToast('举报成功');
     }
   }
@@ -186,11 +186,9 @@ class TeamPostPreviewCard extends StatelessWidget {
           shrinkWrap: true,
           itemCount: provider.post.postInfo.length + (provider.post.repliesCount > 2 ? 1 : 0),
           itemBuilder: (_, index) {
-            if (index == provider.post.postInfo.length)
+            if (index == provider.post.postInfo.length) {
               return Container(
-                margin: EdgeInsets.only(
-                  top: suSetHeight(12.0),
-                ),
+                margin: EdgeInsets.only(top: suSetHeight(12.0)),
                 child: Row(
                   mainAxisAlignment: MainAxisAlignment.center,
                   children: <Widget>[
@@ -213,6 +211,7 @@ class TeamPostPreviewCard extends StatelessWidget {
                   ],
                 ),
               );
+            }
             final _post = provider.post.postInfo[index];
             return Padding(
               padding: EdgeInsets.symmetric(
diff --git a/lib/widgets/custom_switch.dart b/lib/widgets/custom_switch.dart
index 140f4ba2..f7c7b38d 100644
--- a/lib/widgets/custom_switch.dart
+++ b/lib/widgets/custom_switch.dart
@@ -230,10 +230,11 @@ class _RenderCustomSwitch extends RenderConstrainedBox {
     _position
       ..curve = Curves.ease
       ..reverseCurve = Curves.ease.flipped;
-    if (value)
+    if (value) {
       _positionController.forward();
-    else
+    } else {
       _positionController.reverse();
+    }
   }
 
   TickerProvider get vsync => _vsync;
@@ -300,10 +301,11 @@ class _RenderCustomSwitch extends RenderConstrainedBox {
   @override
   void attach(PipelineOwner owner) {
     super.attach(owner);
-    if (value)
+    if (value) {
       _positionController.forward();
-    else
+    } else {
       _positionController.reverse();
+    }
     if (isInteractive) {
       switch (_reactionController.status) {
         case AnimationStatus.forward:
@@ -329,9 +331,11 @@ class _RenderCustomSwitch extends RenderConstrainedBox {
 
   void _handlePositionStateChanged(AnimationStatus status) {
     if (isInteractive) {
-      if (status == AnimationStatus.completed && !_value)
+      if (status == AnimationStatus.completed && !_value) {
         onChanged(true);
-      else if (status == AnimationStatus.dismissed && _value) onChanged(false);
+      } else if (status == AnimationStatus.dismissed && _value) {
+        onChanged(false);
+      }
     }
   }
 
@@ -379,10 +383,11 @@ class _RenderCustomSwitch extends RenderConstrainedBox {
   }
 
   void _handleDragEnd(DragEndDetails details) {
-    if (_position.value >= 0.5)
+    if (_position.value >= 0.5) {
       _positionController.forward();
-    else
+    } else {
       _positionController.reverse();
+    }
     _reactionController.reverse();
   }
 
diff --git a/lib/widgets/dialogs/comment_positioned.dart b/lib/widgets/dialogs/comment_positioned.dart
index 66bf3831..0ad05255 100755
--- a/lib/widgets/dialogs/comment_positioned.dart
+++ b/lib/widgets/dialogs/comment_positioned.dart
@@ -53,10 +53,11 @@ class CommentPositionedState extends State<CommentPositioned> {
   @override
   void initState() {
     super.initState();
-    if (widget.comment != null)
+    if (widget.comment != null) {
       setState(() {
         toComment = widget.comment;
       });
+    }
     _commentController
       ..addListener(() {
         setState(() {
@@ -133,7 +134,7 @@ class CommentPositionedState extends State<CommentPositioned> {
   }
 
   Future _request(context) async {
-    if (commentContent.length <= 0 && _image == null) {
+    if (commentContent.isEmpty && _image == null) {
       showCenterErrorToast('内容不能为空！');
     } else {
       setState(() {
@@ -333,7 +334,7 @@ class CommentPositionedState extends State<CommentPositioned> {
                         color: currentThemeColor,
                       ),
                     ),
-                    onTap: (_commentController.text.length > 0 || _image != null)
+                    onTap: (_commentController.text.isNotEmpty || _image != null)
                         ? () => _request(context)
                         : null,
                   )
diff --git a/lib/widgets/dialogs/confirmation_dialog.dart b/lib/widgets/dialogs/confirmation_dialog.dart
index 8879f948..799a79cf 100644
--- a/lib/widgets/dialogs/confirmation_dialog.dart
+++ b/lib/widgets/dialogs/confirmation_dialog.dart
@@ -234,7 +234,7 @@ class RegExpSpecialTextSpanBuilder extends SpecialTextSpanBuilder {
       });
     }
 
-    if (data.length > 0) {
+    if (data.isNotEmpty) {
       SpecialText specialText;
       String textStack = '';
       for (int i = 0; i < data.length; i++) {
@@ -253,7 +253,7 @@ class RegExpSpecialTextSpanBuilder extends SpecialTextSpanBuilder {
           if (specialText != null) {
             if (textStack.length - specialText.startFlag.length >= 0) {
               textStack = textStack.substring(0, textStack.length - specialText.startFlag.length);
-              if (textStack.length > 0) {
+              if (textStack.isNotEmpty) {
                 inlineList.add(TextSpan(text: textStack, style: textStyle));
               }
             }
@@ -265,7 +265,7 @@ class RegExpSpecialTextSpanBuilder extends SpecialTextSpanBuilder {
       if (specialText != null) {
         inlineList.add(
             TextSpan(text: specialText.startFlag + specialText.getContent(), style: textStyle));
-      } else if (textStack.length > 0) {
+      } else if (textStack.isNotEmpty) {
         inlineList.add(TextSpan(text: textStack, style: textStyle));
       }
     } else {
diff --git a/lib/widgets/dialogs/forward_positioned.dart b/lib/widgets/dialogs/forward_positioned.dart
index 933b9ad7..4f549069 100755
--- a/lib/widgets/dialogs/forward_positioned.dart
+++ b/lib/widgets/dialogs/forward_positioned.dart
@@ -106,32 +106,29 @@ class ForwardPositionedState extends State<ForwardPositioned> {
         maxLines: 3,
       );
 
-  void _request(context) async {
+  Future<void> _request(context) async {
     setState(() {
       _forwarding = true;
     });
     String content;
-    _forwardController.text.length == 0 ? content = '转发' : content = _forwardController.text;
+    _forwardController.text.isEmpty ? content = '转发' : content = _forwardController.text;
 
     /// Sending image if it exist.
     if (_image != null) {
-      Map<String, dynamic> data = (await getImageRequest(createForm(_image))).data;
+      final Map<String, dynamic> data = (await getImageRequest(createForm(_image))).data;
       _imageID = int.parse(data['image_id']);
       content += ' |$_imageID| ';
     }
 
-    PostAPI.postForward(
-      content,
-      widget.post.id,
-      commentAtTheMeanTime,
-    ).then((response) {
+    try {
+      await PostAPI.postForward(content, widget.post.id, commentAtTheMeanTime);
       showToast('转发成功');
       Navigator.of(context).pop();
       Instances.eventBus.fire(PostForwardedEvent(
         widget.post.id,
         widget.post.forwards,
       ));
-    }).catchError((e) {
+    } catch (e) {
       _forwarding = false;
       debugPrint('Forward post failed: $e');
       if (e is DioError && e.response.statusCode == 404) {
@@ -141,7 +138,7 @@ class ForwardPositionedState extends State<ForwardPositioned> {
         showToast('转发失败');
       }
       if (mounted) setState(() {});
-    });
+    }
   }
 
   void updatePadStatus(bool active) {
diff --git a/lib/widgets/dialogs/loading_dialog.dart b/lib/widgets/dialogs/loading_dialog.dart
index d637d976..dc3c10d9 100755
--- a/lib/widgets/dialogs/loading_dialog.dart
+++ b/lib/widgets/dialogs/loading_dialog.dart
@@ -98,7 +98,9 @@ class LoadingDialogState extends State<LoadingDialog> {
             } else {
               Navigator.pop(context);
             }
-          } catch (e) {}
+          } catch (e) {
+            debugPrint('Error when running pop in loading dialog: $e');
+          }
         });
       } else if (this.type == 'dismiss') {
         try {
@@ -107,7 +109,9 @@ class LoadingDialogState extends State<LoadingDialog> {
           } else {
             Navigator.pop(context);
           }
-        } catch (e) {}
+        } catch (e) {
+          debugPrint('Error when running pop in loading dialog: $e');
+        }
       }
     }
     Widget child = Center(
diff --git a/lib/widgets/fab_bottom_appbar.dart b/lib/widgets/fab_bottom_appbar.dart
index 47259adf..3b8b5ff0 100755
--- a/lib/widgets/fab_bottom_appbar.dart
+++ b/lib/widgets/fab_bottom_appbar.dart
@@ -31,9 +31,9 @@ class FABBottomAppBar extends StatefulWidget {
   FABBottomAppBar({
     this.items,
     this.centerItemText,
-    this.height: 64.0,
-    this.iconSize: 28.0,
-    this.itemFontSize: 18.0,
+    this.height = 64.0,
+    this.iconSize = 28.0,
+    this.itemFontSize = 18.0,
     this.backgroundColor,
     this.color,
     this.selectedColor,
diff --git a/lib/widgets/image/image_crop_helper.dart b/lib/widgets/image/image_crop_helper.dart
index 7e1ab838..c4d3806a 100644
--- a/lib/widgets/image/image_crop_helper.dart
+++ b/lib/widgets/image/image_crop_helper.dart
@@ -58,10 +58,13 @@ Future<List<int>> cropImage({ExtendedImageEditorState state}) async {
 
   if (action.needCrop) option.addOption(ClipOption.fromRect(cropRect));
 
-  if (action.needFlip)
+  if (action.needFlip) {
     option.addOption(FlipOption(horizontal: flipHorizontal, vertical: flipVertical));
+  }
 
-  if (action.hasRotateAngle) option.addOption(RotateOption(rotateAngle));
+  if (action.hasRotateAngle) {
+    option.addOption(RotateOption(rotateAngle));
+  }
 
   final result = await ImageEditor.editImage(
     image: img,
diff --git a/lib/widgets/image/image_crop_page.dart b/lib/widgets/image/image_crop_page.dart
index da5d275e..42ce55b5 100755
--- a/lib/widgets/image/image_crop_page.dart
+++ b/lib/widgets/image/image_crop_page.dart
@@ -76,29 +76,27 @@ class _ImageCropPageState extends State<ImageCropPage> {
         targetWidth: 640,
         targetHeight: 640,
       );
-      uploadImage(context, compressedFile);
+      unawaited(uploadImage(context, compressedFile));
     } catch (e) {
       debugPrint('Crop image faild: $e');
       _controller.changeState('failed', '头像更新失败');
     }
   }
 
-  Future uploadImage(context, file) async {
-    final formData = await createForm(file);
-    NetUtils.postWithCookieSet(
-      API.userAvatarUpload,
-      data: formData,
-    ).then((response) {
+  Future<void> uploadImage(context, file) async {
+    try {
+      final formData = await createForm(file);
+      await NetUtils.postWithCookieSet(API.userAvatarUpload, data: formData);
       _controller.changeState('success', '头像更新成功');
       _cropping = false;
       Future.delayed(Duration(milliseconds: 2200), () {
         Navigator.of(context).pop(true);
       });
-    }).catchError((e) {
+    } catch (e) {
       debugPrint(e.toString());
       _controller.changeState('failed', '头像更新失败');
       _cropping = false;
-    });
+    }
   }
 
   Future createForm(File file) async {
diff --git a/lib/widgets/messages/app_message_preview_widget.dart b/lib/widgets/messages/app_message_preview_widget.dart
index cedd62bb..b13db059 100644
--- a/lib/widgets/messages/app_message_preview_widget.dart
+++ b/lib/widgets/messages/app_message_preview_widget.dart
@@ -105,7 +105,9 @@ class _AppMessagePreviewWidgetState extends State<AppMessagePreviewWidget>
       widget.message.content = content['content'];
       Provider.of<MessagesProvider>(currentContext, listen: false).saveAppsMessages();
       if (mounted) setState(() {});
-    } catch (e) {}
+    } catch (e) {
+      return;
+    }
   }
 
   @mustCallSuper
diff --git a/lib/widgets/no_scale_text_widget.dart b/lib/widgets/no_scale_text_widget.dart
index cc07d671..afb395c2 100755
--- a/lib/widgets/no_scale_text_widget.dart
+++ b/lib/widgets/no_scale_text_widget.dart
@@ -1,4 +1,4 @@
-import 'dart:math' as Math;
+import 'dart:math' as math;
 
 import 'package:flutter/material.dart';
 
@@ -28,7 +28,7 @@ class MaxScaleTextWidget extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final data = MediaQuery.of(context);
-    final scale = Math.min(max, data.textScaleFactor);
+    final scale = math.min(max, data.textScaleFactor);
     return MediaQuery(
       data: data.copyWith(textScaleFactor: scale),
       child: child,
diff --git a/lib/widgets/rounded_check_box.dart b/lib/widgets/rounded_check_box.dart
index d7decde7..245f06c5 100755
--- a/lib/widgets/rounded_check_box.dart
+++ b/lib/widgets/rounded_check_box.dart
@@ -362,10 +362,11 @@ class _RenderCheckbox extends RenderToggleable {
 
         _initStrokePaint(paint);
         final double tShrink = (t - 0.5) * 2.0;
-        if (_oldValue == null || value == null)
+        if (_oldValue == null || value == null) {
           _drawDash(canvas, origin, tShrink, paint);
-        else
+        } else {
           _drawCheck(canvas, origin, tShrink, paint);
+        }
       }
     } else {
       // Two cases: null to true, true to null
@@ -376,16 +377,18 @@ class _RenderCheckbox extends RenderToggleable {
       _initStrokePaint(paint);
       if (tNormalized <= 0.5) {
         final double tShrink = 1.0 - tNormalized * 2.0;
-        if (_oldValue == true)
+        if (_oldValue == true) {
           _drawCheck(canvas, origin, tShrink, paint);
-        else
+        } else {
           _drawDash(canvas, origin, tShrink, paint);
+        }
       } else {
         final double tExpand = (tNormalized - 0.5) * 2.0;
-        if (value == true)
+        if (value == true) {
           _drawCheck(canvas, origin, tExpand, paint);
-        else
+        } else {
           _drawDash(canvas, origin, tExpand, paint);
+        }
       }
     }
   }
diff --git a/lib/widgets/webview/in_app_webview.dart b/lib/widgets/webview/in_app_webview.dart
index 7929bbfc..269a191b 100755
--- a/lib/widgets/webview/in_app_webview.dart
+++ b/lib/widgets/webview/in_app_webview.dart
@@ -97,12 +97,14 @@ class _InAppBrowserPageState extends State<InAppBrowserPage> with AutomaticKeepA
       debugPrint('Found scheme when load: $url');
       if (Platform.isAndroid) {
         Future.delayed(1.microseconds, () async {
-          controller.stopLoading();
+          unawaited(controller.stopLoading());
           debugPrint('Try to launch intent...');
           final appName = await ChannelUtils.getSchemeLaunchAppName(url);
           if (appName != null) {
             final shouldLaunch = await waitForConfirmation(appName);
-            if (shouldLaunch) _launchURL(url: url);
+            if (shouldLaunch) {
+              await _launchURL(url: url);
+            }
           }
         });
       }
@@ -187,7 +189,7 @@ class _InAppBrowserPageState extends State<InAppBrowserPage> with AutomaticKeepA
     );
   }
 
-  Future<void> showMore(context) async {
+  void showMore(context) {
     showModalBottomSheet(
       shape: RoundedRectangleBorder(
         borderRadius: BorderRadius.only(