properly enforce password and username restrictions

management/lib/pages/register_page.dart

@@ -54,9 +54,13 @@ class _RegisterPageState extends State<RegisterPage> {
                 decoration: InputDecoration(
                   labelText: 'Passwort',
                   suffix: IconButton(
-                    icon: Icon(Icons.remove_red_eye_rounded,
-                        color: _showPassword ? primary : darkGrey),
                     onPressed: () => setState(() => _showPassword = !_showPassword),
+                    icon: Icon(
+                      Icons.remove_red_eye_rounded,
+                      color: _showPassword ? secondary : darkGrey,
+                    ),
+                    constraints: const BoxConstraints(maxWidth: 24.0),
+                    padding: EdgeInsets.zero,
                   ),
                 ),
                 onChanged: (String input) => setState(() => _password = input),
@@ -121,6 +125,6 @@ class _RegisterPageState extends State<RegisterPage> {
     if (empty != null) {
       return empty;
     }
-    return input!.length > 5 ? null : 'Das Passwort muss mindestens 6 Zeichen enthalten';
+    return input!.length > 4 ? null : 'Das Passwort muss mindestens 5 Zeichen enthalten';
   }
 }

management/lib/widgets/user_dialog.dart

@@ -28,6 +28,8 @@ class _UserDialogState extends State<UserDialog> {
 
   bool _showPassword = false;
 
+  final GlobalKey<FormState> _formKey = GlobalKey();
+
   @override
   Widget build(BuildContext context) {
     return ContentDialog(
@@ -36,12 +38,15 @@ class _UserDialogState extends State<UserDialog> {
         Padding(
           padding: const EdgeInsets.only(bottom: 8.0),
           child: Form(
+            key: _formKey,
             child: Column(
               children: [
                 TextFormField(
                   decoration: const InputDecoration(labelText: 'Nutzername'),
                   onChanged: (String input) => _user!.username = input,
                   controller: TextEditingController(text: _user!.username),
+                  validator: (String? input) =>
+                      input == null || input.isEmpty ? 'Pflichtfeld' : null,
                 ),
                 if (widget.user == null)
                   TextFormField(
@@ -59,6 +64,11 @@ class _UserDialogState extends State<UserDialog> {
                     ),
                     onChanged: (String input) => _password = input,
                     controller: TextEditingController(text: _password ?? ''),
+                    validator: (String? input) => (input?.length ?? 0) < 5
+                        ? 'Das Passwort muss mindestens 5 Zeichen enthalten'
+                        : input == null || input.isEmpty
+                            ? 'Pflichtfeld'
+                            : null,
                     obscureText: !_showPassword,
                   ),
                 TextFormField(
@@ -95,8 +105,11 @@ class _UserDialogState extends State<UserDialog> {
           child: const Text('Abbrechen'),
         ),
         ElevatedButton(
-          onPressed: () =>
-              Navigator.of(context).pop(UserResult(save: true, user: _user, password: _password)),
+          onPressed: () {
+            if (_formKey.currentState?.validate() ?? false) {
+              Navigator.of(context).pop(UserResult(save: true, user: _user, password: _password));
+            }
+          },
           child: const Text('Speichern'),
         ),
       ],