Added simple validators

lib/src/address_controller.dart

@@ -0,0 +1,13 @@
+import 'package:flutter/foundation.dart';
+
+class AddressController extends ChangeNotifier {
+  final String zipcode;
+  final int houseNumber;
+  final String prefix;
+  final String street;
+  final String city;
+
+  AddressController(this.zipcode, this.houseNumber, this.prefix, this.street, this.city);
+
+  
+}

lib/src/address_form.dart

@@ -1,8 +1,8 @@
 import 'package:flutter/material.dart';
-import 'package:flutter/widgets.dart';
+import 'package:flutter_address_form/src/models/address.dart';
 
 class AddressForm extends StatefulWidget {
-  AddressForm({Key? key}) : super(key: key);
+  const AddressForm({Key? key}) : super(key: key);
 
   @override
   State<AddressForm> createState() => _AddressFormState();
@@ -10,58 +10,146 @@ class AddressForm extends StatefulWidget {
 
 class _AddressFormState extends State<AddressForm> {
   final TextEditingController _zipcodeController = TextEditingController();
+  final TextEditingController _houseNumberController = TextEditingController();
+  final TextEditingController _prefixController = TextEditingController();
+  final TextEditingController _streetController = TextEditingController();
+  final TextEditingController _cityController = TextEditingController();
+
   final RegExp _zipcodeRegExp = RegExp(r'^[1-9][0-9]{3}\s?[a-zA-Z]{2}$');
   @override
   Widget build(BuildContext context) {
-    return Form(
-      child: Column(
+    return Column(
       children: [
-          _createField(
-            label: 'Postcode',
+        AddressFormTextField(
           controller: _zipcodeController,
+          validator: (text) {
+            if (text.isEmpty) {
+              return 'Can\'t be empty';
+            }
+            if (!_zipcodeRegExp.hasMatch(text)) {
+              return 'Invalid zipcode';
+            }
+            return null;
+          },
+          label: 'Postcode',
         ),
         Flexible(
           child: Row(
             children: [
-                _createField(
+              AddressFormTextField(
+                controller: _houseNumberController,
+                validator: (text) {
+                  if (text.isEmpty) {
+                    return 'Can\'t be empty';
+                  }
+                  if (text.length >= 3 || int.tryParse(text) == null) {
+                    return 'Invalid number';
+                  }
+                  return null;
+                },
                 label: 'Huisnummer',
-                  controller: TextEditingController(),
               ),
-                _createField(
+              AddressFormTextField(
+                controller: _prefixController,
+                validator: (text) {
+                  if (text.isEmpty) {
+                    return 'Can\'t be empty';
+                  }
+                  if (RegExp(r'/^[a-z]*$/').hasMatch(text) &&
+                      text.length != 1) {
+                    return 'Invalid prefix';
+                  }
+                  return null;
+                },
                 label: 'Toevoeging',
-                  controller: TextEditingController(),
               ),
             ],
           ),
         ),
-          _createField(
+        AddressFormTextField(
+          controller: _streetController,
+          validator: (text) {
+            if (text.isEmpty) {
+              return 'Can\'t be empty';
+            }
+            return null;
+          },
           label: 'Straatnaam',
-            controller: TextEditingController(),
         ),
-          _createField(
+        AddressFormTextField(
+          controller: _cityController,
+          validator: (text) {
+            if (text.isEmpty) {
+              return 'Can\'t be empty';
+            }
+            return null;
+          },
           label: 'Woonplaats',
-            controller: TextEditingController(),
+        ),
+        TextButton(
+          onPressed: () {},
+          child: Text('Test'),
         )
       ],
-      ),
     );
   }
 
-  Widget _createField(
-      {required String label, required TextEditingController controller}) {
+  @override
+  void dispose() {
+    _zipcodeController.dispose();
+    _houseNumberController.dispose();
+    _prefixController.dispose();
+    _streetController.dispose();
+    _cityController.dispose();
+    super.dispose();
+  }
+}
+
+class AddressFormTextField extends StatefulWidget {
+  final String label;
+  final TextEditingController controller;
+  final String? Function(String) validator;
+  AddressFormTextField({
+    Key? key,
+    required this.label,
+    required this.controller,
+    required this.validator,
+  }) : super(key: key);
+
+  @override
+  State<AddressFormTextField> createState() => _AddressFormTextFieldState();
+}
+
+class _AddressFormTextFieldState extends State<AddressFormTextField> {
+  final Address addressModel = Address();
+
+  String? get _errorText {
+    final text = widget.controller.value.text;
+    return widget.validator(text);
+  }
+
+  @override
+  void initState() {
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ValueListenableBuilder<TextEditingValue>(
+        valueListenable: widget.controller,
+        builder: (context, value, _) {
           return Flexible(
             child: Container(
               margin: const EdgeInsets.all(10),
-        child: TextFormField(
-          validator: (value) {
-            print(_zipcodeRegExp.hasMatch(value!));
-          },
+              child: TextField(
+                controller: widget.controller,
                 decoration: InputDecoration(
-            label: Text(label),
+                    label: Text(widget.label),
                     border: const OutlineInputBorder(),
-          ),
+                    errorText: _errorText),
               ),
             ),
           );
+        });
   }
 }

lib/src/models/address.dart

@@ -0,0 +1,30 @@
+class Address {
+  Address({
+    this.zipcode,
+    this.street,
+    this.housenumber,
+    this.suffix,
+    this.city,
+  });
+
+  final String? zipcode;
+  final String? street;
+  final int? housenumber;
+  final String? suffix;
+  final String? city;
+
+  Address copyWith({
+    String? zipcode,
+    String? street,
+    int? housenumber,
+    String? suffix,
+    String? city,
+  }) =>
+      Address(
+        zipcode: zipcode ?? this.zipcode,
+        street: street ?? this.street,
+        housenumber: housenumber ?? this.housenumber,
+        suffix: suffix ?? this.suffix,
+        city: city ?? this.city,
+      );
+}