Frontend first draft

frontend/pweb/lib/widgets/text_field.dart

@@ -0,0 +1,38 @@
+import 'package:flutter/material.dart';
+
+
+class NotEmptyTextFormField extends StatelessWidget {
+  final String labelText;
+  final String error;
+  final TextEditingController controller;
+  final ValueChanged<bool>? onValid;
+  final String? hintText;
+  final bool readOnly;
+
+  const NotEmptyTextFormField({
+    super.key,
+    required this.controller,
+    required this.labelText,
+    required this.error,
+    this.onValid,
+    this.hintText,
+    required this.readOnly,
+  });
+
+  bool _validate(String? value) {
+    return !(value == null || value.isNotEmpty);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return TextFormField(
+      controller: controller,
+      decoration: InputDecoration(labelText: labelText, hintText: hintText),
+      validator: (value) => _validate(value) ? error : null,
+      onChanged: (value) {
+        if (onValid != null) onValid!(_validate(value));
+      },
+      readOnly: readOnly,
+    );
+  }
+}