Make proper use of Material3 colour schemes.

This is a big improvement over what we had before and relies on the
theme to provide dark mode rather than manually checking brightness each
time we pick a colour.

The buttons in the primary container aren't quite right, I'm not sure
why.

lib/src/app.dart

@@ -22,6 +22,26 @@ class App extends StatefulWidget {
 }
 
 class _AppState extends State<App> with PreferencesMixin {
+  // Define the primary dark grey color.
+  static const int _darkGreyPrimaryValue = 0xFF424242;
+
+  // Create a map of shades for the dark grey color.
+  static const MaterialColor darkGrey = MaterialColor(
+    _darkGreyPrimaryValue,
+    <int, Color>{
+      50: Color(0xFFE0E0E0),
+      100: Color(0xFFBDBDBD),
+      200: Color(0xFF9E9E9E),
+      300: Color(0xFF757575),
+      400: Color(0xFF616161),
+      500: Color(_darkGreyPrimaryValue),
+      600: Color(0xFF3D3D3D),
+      700: Color(0xFF333333),
+      800: Color(0xFF2B2B2B),
+      900: Color(0xFF1C1C1C),
+    },
+  );
+
   @override
   Widget build(BuildContext context) {
     return FutureBuilder<SharedPreferences>(
@@ -39,8 +59,21 @@ class _AppState extends State<App> with PreferencesMixin {
           }
           return Consumer<AppSettings>(
             builder: (context, appSettings, _) => MaterialApp(
-              theme: ThemeData(primarySwatch: Colors.pink),
+              theme: ThemeData(
-              darkTheme: ThemeData.dark(),
+                  useMaterial3: true,
+                  colorScheme:  ColorScheme.fromSwatch(
+                    primarySwatch: Colors.pink,
+                    backgroundColor: Colors.white,
+                  )
+              ),
+              darkTheme: ThemeData(
+                useMaterial3: true,
+                colorScheme: ColorScheme.fromSwatch(
+                  primarySwatch: darkGrey,
+                  backgroundColor: darkGrey.shade700,
+                  brightness: Brightness.dark,
+                ),
+              ),
               themeMode: appSettings.themeMode,
               home: AppVersion.packageInfo == null
                   ? const DebgetNotFoundPage()

lib/src/pages/main_page.dart

@@ -26,6 +26,8 @@ class _MainPageState extends State<MainPage> {
     return Scaffold(
       appBar: AppBar(
         title: Text(context.t('Main menu')),
+        backgroundColor: Theme.of(context).colorScheme.primary,
+        foregroundColor: Theme.of(context).colorScheme.onPrimary,
       ),
       drawer: const LeftMenu(),
       body: const Column(

lib/src/pages/manager.dart

@@ -174,9 +174,7 @@ class _ManagerState extends State<Manager> with PreferencesMixin {
 
   Widget _buildVmList() {
     List<Widget> widgetList = [];
-    final Color buttonColor = Theme.of(context).brightness == Brightness.dark
+    final Color buttonColor = Theme.of(context).colorScheme.primary;
-        ? Colors.white70
-        : Theme.of(context).colorScheme.primary;
     widgetList.addAll(
       [
         Padding(
@@ -186,30 +184,30 @@ class _ManagerState extends State<Manager> with PreferencesMixin {
             children: [
               Text(
                 "${context.t('Directory where the machines are stored')}:",
+                style: TextStyle(
+                  color: Theme.of(context).colorScheme.onSurface,
+                ),
               ),
               const SizedBox(
                 width: 8,
               ),
-              Text.rich(
+              ElevatedButton(
-                TextSpan(
+                style: ElevatedButton.styleFrom(
-                  recognizer: TapGestureRecognizer()
+                  foregroundColor: Theme.of(context).colorScheme.onSurface,
-                    ..onTap = () async {
+                  backgroundColor: Theme.of(context).colorScheme.surface,
-                      String? result =
-                          await FilePicker.platform.getDirectoryPath();
-                      if (result != null) {
-                        setState(() {
-                          Directory.current = result;
-                        });
-
-                        savePreference(
-                            prefWorkingDirectory, Directory.current.path);
-                        _getVms(context);
-                      }
-                    },
-                  text: Directory.current.path,
-                  style:
-                      TextStyle(color: Theme.of(context).colorScheme.primary),
                 ),
+                onPressed: () async {
+                  var folder = await FilePicker.platform
+                      .getDirectoryPath(dialogTitle: "Pick a folder");
+                  if (folder != null) {
+                    setState(() {
+                      Directory.current = folder;
+                    });
+                    savePreference(
+                        prefWorkingDirectory, Directory.current.path);
+                  }
+                },
+                child: Text(Directory.current.path),
               ),
             ],
           ),

lib/src/widgets/downloader/cancel_dismiss_button.dart

@@ -21,9 +21,7 @@ class CancelDismissButton extends StatelessWidget {
           ElevatedButton(
             style: ElevatedButton.styleFrom(
               backgroundColor: Theme.of(context).colorScheme.surface,
-              foregroundColor: Theme.of(context).brightness == Brightness.dark
+              foregroundColor: Theme.of(context).colorScheme.onSurface,
-                  ? Colors.white70
-                  : Theme.of(context).colorScheme.primary,
             ),
             onPressed: !downloadFinished
                 ? onCancel

lib/src/widgets/home_page/downloader_menu.dart

@@ -31,9 +31,7 @@ class _DownloaderMenuState extends State<DownloaderMenu> with PreferencesMixin {
   Widget build(BuildContext context) {
     return Expanded(
       child: Container(
-        color: Theme.of(context).brightness == Brightness.dark
+        color: Theme.of(context).colorScheme.primaryContainer,
-            ? Theme.of(context).colorScheme.surface
-            : Theme.of(context).colorScheme.primary,
         child: Column(
           children: [
             Padding(
@@ -44,9 +42,7 @@ class _DownloaderMenuState extends State<DownloaderMenu> with PreferencesMixin {
                   Text(
                     "${context.t('Directory where the machines are stored')}:",
                     style: TextStyle(
-                      color: Theme.of(context).brightness == Brightness.dark
+                      color: Theme.of(context).colorScheme.onPrimaryContainer,
-                        ? Theme.of(context).colorScheme.onSurface
-                        : Theme.of(context).colorScheme.onPrimary,
                     ),
                   ),
                   const SizedBox(
@@ -54,10 +50,8 @@ class _DownloaderMenuState extends State<DownloaderMenu> with PreferencesMixin {
                   ),
                   ElevatedButton(
                     style: ElevatedButton.styleFrom(
-                      foregroundColor: Theme.of(context).brightness == Brightness.dark
+                      foregroundColor: Theme.of(context).colorScheme.onSurface,
-                          ? Colors.white70
+                      backgroundColor: Theme.of(context).colorScheme.surface,
-                          : Theme.of(context).colorScheme.primary,
-                      backgroundColor: Theme.of(context).canvasColor,
                     ),
                     onPressed: () async {
                       var folder = await FilePicker.platform

lib/src/widgets/home_page/downloader_page_button.dart

@@ -35,10 +35,8 @@ class DownloaderPageButton extends StatelessWidget {
             ),
             ElevatedButton(
               style: ElevatedButton.styleFrom(
-                foregroundColor: Theme.of(context).brightness == Brightness.dark
+                foregroundColor: Theme.of(context).colorScheme.onSurface,
-                    ? Colors.white70
+                backgroundColor: Theme.of(context).colorScheme.surface,
-                    : Theme.of(context).colorScheme.primary,
-                backgroundColor: Theme.of(context).canvasColor,
               ),
               onPressed: onPressed,
               child: Padding(

lib/src/widgets/home_page/home_page_button.dart

@@ -32,10 +32,8 @@ class HomePageButton extends StatelessWidget {
             ),
             ElevatedButton(
               style: ElevatedButton.styleFrom(
-                backgroundColor: Theme.of(context).canvasColor,
+                backgroundColor: Theme.of(context).colorScheme.surface,
-                foregroundColor: Theme.of(context).brightness == Brightness.dark
+                foregroundColor: Theme.of(context).colorScheme.onSurface,
-                    ? Colors.white70
-                    : Theme.of(context).colorScheme.primary,
               ),
               onPressed: onPressed,
               child: Padding(

lib/src/widgets/home_page/main_menu.dart

@@ -12,9 +12,7 @@ class MainMenu extends StatelessWidget {
   Widget build(BuildContext context) {
     return Expanded(
       child: Container(
-        color: Theme.of(context).brightness == Brightness.dark
+        color: Theme.of(context).colorScheme.primaryContainer,
-            ? Theme.of(context).colorScheme.surface
-            : Theme.of(context).colorScheme.primary,
         child: Padding(
           padding: const EdgeInsets.all(8.0),
           child: Row(

lib/src/widgets/left_menu.dart

@@ -58,11 +58,15 @@ class _LeftMenuState extends State<LeftMenu> with PreferencesMixin {
                       child: Container(),
                     ),
                     Switch(
-                      value: Theme.of(context).brightness == Brightness.dark,
+                      value: Theme.of(context).colorScheme.brightness == Brightness.dark,
                       onChanged: (value) {
                         appSettings.useDarkMode = value;
                         savePreference(prefThemeMode, value);
                       },
+                      activeColor: Colors.white,
+                      activeTrackColor: Colors.black26,
+                      inactiveThumbColor: Theme.of(context).colorScheme.onPrimary,
+                      inactiveTrackColor: Theme.of(context).colorScheme.primary,
                     ),
                   ],
                 ),