diff --git a/lib/scaffolds/list_stateful.dart b/lib/scaffolds/list_stateful.dart
index e307fb7..c3a1e96 100644
--- a/lib/scaffolds/list_stateful.dart
+++ b/lib/scaffolds/list_stateful.dart
@@ -213,7 +213,7 @@ class _ListStatefulScaffoldState<T, K>
     return CommonScaffold(
       title: widget.title,
       body: _buildBody(),
-      action: widget.actionBuilder == null ? null : widget.actionBuilder!(),
+      action: widget.actionBuilder?.call(),
     );
   }
 }
diff --git a/lib/screens/bb_repo.dart b/lib/screens/bb_repo.dart
index 5587443..6ca34ff 100644
--- a/lib/screens/bb_repo.dart
+++ b/lib/screens/bb_repo.dart
@@ -64,7 +64,7 @@ class BbRepoScreen extends StatelessWidget {
                   text: Text('Code'),
                   rightWidget: Text(filesize(p.size)),
                   url:
-                      '/bitbucket/$owner/$name/src/${branch == null ? p.mainbranch!.name : branch}',
+                      '/bitbucket/$owner/$name/src/${branch ?? p.mainbranch!.name}',
                 ),
                 TableViewItem(
                   leftIconData: Octicons.issue_opened,
@@ -80,16 +80,15 @@ class BbRepoScreen extends StatelessWidget {
                   leftIconData: Octicons.history,
                   text: Text('Commits'),
                   url:
-                      '/bitbucket/$owner/$name/commits/${branch == null ? p.mainbranch!.name : branch}',
+                      '/bitbucket/$owner/$name/commits/${branch ?? p.mainbranch!.name}',
                 ),
                 if (branches != null)
                   TableViewItem(
                     leftIconData: Octicons.git_branch,
                     text: Text(AppLocalizations.of(context)!.branches),
-                    rightWidget: Text(
-                        (branch == null ? p.mainbranch!.name : branch)! +
-                            ' • ' +
-                            branches.length.toString()),
+                    rightWidget: Text((branch ?? p.mainbranch!.name)! +
+                        ' • ' +
+                        branches.length.toString()),
                     onTap: () async {
                       if (branches.length < 2) return;
 
diff --git a/lib/screens/ge_repo.dart b/lib/screens/ge_repo.dart
index d3b8415..a611f29 100644
--- a/lib/screens/ge_repo.dart
+++ b/lib/screens/ge_repo.dart
@@ -139,8 +139,7 @@ class GeRepoScreen extends StatelessWidget {
                   leftIconData: Octicons.code,
                   text: Text('Code'),
                   rightWidget: Text(p.license ?? ''),
-                  url:
-                      '/gitee/$owner/$name/tree/${branch == null ? p.defaultBranch : branch}',
+                  url: '/gitee/$owner/$name/tree/${branch ?? p.defaultBranch}',
                 ),
                 TableViewItem(
                   leftIconData: Octicons.issue_opened,
@@ -158,16 +157,15 @@ class GeRepoScreen extends StatelessWidget {
                   leftIconData: Octicons.history,
                   text: Text('Commits'),
                   url:
-                      '/gitee/$owner/$name/commits?branch=${branch == null ? p.defaultBranch : branch}',
+                      '/gitee/$owner/$name/commits?branch=${branch ?? p.defaultBranch}',
                 ),
                 if (branches != null)
                   TableViewItem(
                     leftIconData: Octicons.git_branch,
                     text: Text(AppLocalizations.of(context)!.branches),
-                    rightWidget: Text(
-                        (branch == null ? p.defaultBranch : branch)! +
-                            ' • ' +
-                            branches.length.toString()),
+                    rightWidget: Text((branch ?? p.defaultBranch)! +
+                        ' • ' +
+                        branches.length.toString()),
                     onTap: () async {
                       if (branches.length < 2) return;
 
diff --git a/lib/screens/gh_object.dart b/lib/screens/gh_object.dart
index 350efc9..798c8d7 100644
--- a/lib/screens/gh_object.dart
+++ b/lib/screens/gh_object.dart
@@ -22,7 +22,7 @@ class GhObjectScreen extends StatelessWidget {
   Widget build(BuildContext context) {
     return RefreshStatefulScaffold<RepositoryContents>(
       // canRefresh: !_isImage, // TODO:
-      title: AppBarTitle(path == null ? 'Files' : path),
+      title: AppBarTitle(path ?? 'Files'),
       fetch: () async {
         // Do not request again for images
         if (path != null &&
diff --git a/lib/screens/gl_project.dart b/lib/screens/gl_project.dart
index 317cb80..59a3b59 100644
--- a/lib/screens/gl_project.dart
+++ b/lib/screens/gl_project.dart
@@ -199,17 +199,16 @@ class GlProjectScreen extends StatelessWidget {
                       ? null
                       : Text(p.statistics!.commitCount.toString()),
                   url:
-                      '/gitlab/projects/$id/commits?prefix=$prefix&branch=${branch == null ? p.defaultBranch : branch}', // EDIT
+                      '/gitlab/projects/$id/commits?prefix=$prefix&branch=${branch ?? p.defaultBranch}', // EDIT
                 ),
                 if (branches != null)
                   TableViewItem(
                     leftIconData: Octicons.git_branch,
                     text: Text(AppLocalizations.of(context)!.branches),
-                    rightWidget: Text(
-                        ((branch == null ? p.defaultBranch : branch) ??
-                                '' /** empty project */) +
-                            ' • ' +
-                            branches.length.toString()),
+                    rightWidget: Text(((branch ?? p.defaultBranch) ??
+                            '' /** empty project */) +
+                        ' • ' +
+                        branches.length.toString()),
                     onTap: () async {
                       if (branches.length < 2) return;
 
diff --git a/lib/screens/go_object.dart b/lib/screens/go_object.dart
index 6b5467c..349414a 100644
--- a/lib/screens/go_object.dart
+++ b/lib/screens/go_object.dart
@@ -57,8 +57,7 @@ class GoObjectScreen extends StatelessWidget {
           ]);
         } else {
           final v = GogsBlob.fromJson(p);
-          return BlobView(v.name,
-              base64Text: v.content == null ? '' : v.content);
+          return BlobView(v.name, base64Text: v.content);
         }
       },
     );
diff --git a/lib/screens/go_repo.dart b/lib/screens/go_repo.dart
index 445ce61..8b3eb55 100644
--- a/lib/screens/go_repo.dart
+++ b/lib/screens/go_repo.dart
@@ -94,8 +94,7 @@ class GoRepoScreen extends StatelessWidget {
                 TableViewItem(
                   leftIconData: Octicons.code,
                   text: Text('Code'),
-                  url:
-                      '/gogs/$owner/$name/blob?ref=${branch == null ? 'master' : branch}',
+                  url: '/gogs/$owner/$name/blob?ref=${branch ?? 'master'}',
                 ),
                 TableViewItem(
                   leftIconData: Octicons.issue_opened,
@@ -110,13 +109,12 @@ class GoRepoScreen extends StatelessWidget {
                 TableViewItem(
                   leftIconData: Octicons.history,
                   text: Text('Commits'),
-                  url:
-                      '/gogs/$owner/$name/commits?ref=${branch == null ? 'master' : branch}',
+                  url: '/gogs/$owner/$name/commits?ref=${branch ?? 'master'}',
                 ),
                 TableViewItem(
                   leftIconData: Octicons.git_branch,
                   text: Text(AppLocalizations.of(context)!.branches),
-                  rightWidget: Text((branch == null ? 'master' : branch)! +
+                  rightWidget: Text((branch ?? 'master')! +
                       ' • ' +
                       '${branches == null ? '1' : branches.length.toString()}'),
                   onTap: () async {