Add error status to data sync component.

lib/components/message.dart

@@ -125,11 +125,11 @@ class OverlayWidgetState extends State<OverlayWidget> {
 void showDialogMessage(BuildContext context, String title, String message) {
   showDialog(
     context: context,
-    builder: (context) => AlertDialog(
+    builder: (context) => ContentDialog(
-      title: Text(title),
+      title: title,
-      content: Text(message),
+      content: Text(message).paddingHorizontal(16),
       actions: [
-        TextButton(
+        FilledButton(
           onPressed: context.pop,
           child: Text("OK".tl),
         )

lib/pages/home_page.dart

@@ -162,16 +162,50 @@ class _SyncDataWidgetState extends State<_SyncDataWidget>
             trailing: Row(
               mainAxisSize: MainAxisSize.min,
               children: [
+                if (DataSync().lastError != null)
+                  InkWell(
+                    borderRadius: BorderRadius.circular(16),
+                    onTap: () {
+                      showDialogMessage(
+                        App.rootContext,
+                        "Error".tl,
+                        DataSync().lastError!,
+                      );
+                    },
+                    child: Container(
+                      padding: const EdgeInsets.symmetric(
+                        horizontal: 8,
+                        vertical: 4,
+                      ),
+                      decoration: BoxDecoration(
+                        color: context.colorScheme.errorContainer,
+                        borderRadius: BorderRadius.circular(16),
+                      ),
+                      child: Row(
+                        children: [
+                          Icon(
+                            Icons.error_outline,
+                            color: Colors.red,
+                            size: 18,
+                          ),
+                          const SizedBox(width: 4),
+                          Text('Error'.tl, style: ts.s12),
+                        ],
+                      ),
+                    ),
+                  ).paddingRight(4),
                 IconButton(
-                    icon: const Icon(Icons.cloud_upload_outlined),
+                  icon: const Icon(Icons.cloud_upload_outlined),
-                    onPressed: () async {
+                  onPressed: () async {
-                      DataSync().uploadData();
+                    DataSync().uploadData();
-                    }),
+                  },
+                ),
                 IconButton(
-                    icon: const Icon(Icons.cloud_download_outlined),
+                  icon: const Icon(Icons.cloud_download_outlined),
-                    onPressed: () async {
+                  onPressed: () async {
-                      DataSync().downloadData();
+                    DataSync().downloadData();
-                    }),
+                  },
+                ),
               ],
             ),
           ),
@@ -538,7 +572,8 @@ class _ImportComicsWidgetState extends State<_ImportComicsWidget> {
             ],
           ),
           onPressed: () {
-            launchUrlString("https://github.com/venera-app/venera/blob/master/doc/import_comic.md");
+            launchUrlString(
+                "https://github.com/venera-app/venera/blob/master/doc/import_comic.md");
           },
         ).fixWidth(90).paddingRight(8),
         Button.filled(
@@ -697,14 +732,24 @@ class _ComicSourceWidgetState extends State<_ComicSourceWidget> {
                   child: Row(
                     mainAxisSize: MainAxisSize.min,
                     children: [
-                      Icon(Icons.update, color: context.colorScheme.primary, size: 20,),
+                      Icon(
+                        Icons.update,
+                        color: context.colorScheme.primary,
+                        size: 20,
+                      ),
                       const SizedBox(width: 8),
-                      Text("@c updates".tlParams({
+                      Text(
-                        'c': _availableUpdates,
+                        "@c updates".tlParams({
-                      }), style: ts.withColor(context.colorScheme.primary),),
+                          'c': _availableUpdates,
+                        }),
+                        style: ts.withColor(context.colorScheme.primary),
+                      ),
                     ],
                   ),
-                ).toAlign(Alignment.centerLeft).paddingHorizontal(16).paddingBottom(8),
+                )
+                    .toAlign(Alignment.centerLeft)
+                    .paddingHorizontal(16)
+                    .paddingBottom(8),
             ],
           ),
         ),
@@ -844,7 +889,8 @@ class _ImageFavoritesState extends State<ImageFavorites> {
                         padding: const EdgeInsets.symmetric(
                             horizontal: 8, vertical: 2),
                         decoration: BoxDecoration(
-                          color: Theme.of(context).colorScheme.secondaryContainer,
+                          color:
+                              Theme.of(context).colorScheme.secondaryContainer,
                           borderRadius: BorderRadius.circular(8),
                         ),
                         child: Text(

lib/utils/data_sync.dart

@@ -40,7 +40,11 @@ class DataSync with ChangeNotifier {
 
   bool get isUploading => _isUploading;
 
-  bool haveWaitingTask = false;
+  bool _haveWaitingTask = false;
+
+  String? _lastError;
+
+  String? get lastError => _lastError;
 
   bool get isEnabled {
     var config = appdata.settings['webdav'];
@@ -64,17 +68,19 @@ class DataSync with ChangeNotifier {
 
   Future<Res<bool>> uploadData() async {
     if (isDownloading) return const Res(true);
-    if (haveWaitingTask) return const Res(true);
+    if (_haveWaitingTask) return const Res(true);
     while (isUploading) {
-      haveWaitingTask = true;
+      _haveWaitingTask = true;
       await Future.delayed(const Duration(milliseconds: 100));
     }
-    haveWaitingTask = false;
+    _haveWaitingTask = false;
     _isUploading = true;
+    _lastError = null;
     notifyListeners();
     try {
       var config = _validateConfig();
       if (config == null) {
+        _lastError = 'Invalid WebDAV configuration';
         return const Res.error('Invalid WebDAV configuration');
       }
       if (config.isEmpty) {
@@ -98,13 +104,6 @@ class DataSync with ChangeNotifier {
         ),
       );
 
-      try {
-        await client.ping();
-      } catch (e) {
-        Log.error("Upload Data", 'Failed to connect to WebDAV server');
-        return const Res.error('Failed to connect to WebDAV server');
-      }
-
       try {
         appdata.settings['dataVersion']++;
         await appdata.saveData(false);
@@ -131,6 +130,7 @@ class DataSync with ChangeNotifier {
         return const Res(true);
       } catch (e, s) {
         Log.error("Upload Data", e, s);
+        _lastError = e.toString();
         return Res.error(e.toString());
       }
     } finally {
@@ -140,17 +140,19 @@ class DataSync with ChangeNotifier {
   }
 
   Future<Res<bool>> downloadData() async {
-    if (haveWaitingTask) return const Res(true);
+    if (_haveWaitingTask) return const Res(true);
     while (isDownloading || isUploading) {
-      haveWaitingTask = true;
+      _haveWaitingTask = true;
       await Future.delayed(const Duration(milliseconds: 100));
     }
-    haveWaitingTask = false;
+    _haveWaitingTask = false;
     _isDownloading = true;
+    _lastError = null;
     notifyListeners();
     try {
       var config = _validateConfig();
       if (config == null) {
+        _lastError = 'Invalid WebDAV configuration';
         return const Res.error('Invalid WebDAV configuration');
       }
       if (config.isEmpty) {
@@ -174,13 +176,6 @@ class DataSync with ChangeNotifier {
         ),
       );
 
-      try {
-        await client.ping();
-      } catch (e) {
-        Log.error("Data Sync", 'Failed to connect to WebDAV server');
-        return const Res.error('Failed to connect to WebDAV server');
-      }
-
       try {
         var files = await client.readDir('/');
         files.sort((a, b) => b.name!.compareTo(a.name!));
@@ -206,6 +201,7 @@ class DataSync with ChangeNotifier {
         return const Res(true);
       } catch (e, s) {
         Log.error("Data Sync", e, s);
+        _lastError = e.toString();
         return Res.error(e.toString());
       }
     } finally {