rework import screen

- validate input to be a url
- enable submitting with the keyboard

Author: Leptopoda

lib/src/screens/form/recipe_import_form.dart

@@ -5,6 +5,7 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:flutter_spinkit/flutter_spinkit.dart';
 import 'package:flutter_translate/flutter_translate.dart';
 import 'package:nextcloud_cookbook_flutter/src/blocs/recipe/recipe_bloc.dart';
+import 'package:nextcloud_cookbook_flutter/src/util/url_validator.dart';
 
 class RecipeImportForm extends StatefulWidget {
   final String importUrl;
@@ -17,6 +18,7 @@ class RecipeImportForm extends StatefulWidget {
 
 class _RecipeImportFormState extends State<RecipeImportForm> {
   late TextEditingController _importUrlController;
+  final _formKey = GlobalKey<FormState>();
 
   @override
   void initState() {
@@ -42,25 +44,61 @@ class _RecipeImportFormState extends State<RecipeImportForm> {
     return BlocBuilder<RecipeBloc, RecipeState>(
       builder: (BuildContext context, RecipeState state) {
         final enabled = state.status != RecipeStatus.updateInProgress;
+
+        void onSubmit() {
+          if (_formKey.currentState!.validate() && enabled) {
+            _formKey.currentState!.save();
+          }
+        }
+
+        String? validate(String? value) {
+          if (value == null || value.isEmpty) {
+            return translate(
+              'login.server_url.validator.pattern',
+            );
+          }
+
+          if (!URLUtils.isValid(value)) {
+            return translate(
+              'login.server_url.validator.pattern',
+            );
+          }
+
+          return null;
+        }
+
+        Future<void> pasteClipboard() async {
+          final clipboard = await Clipboard.getData('text/plain');
+          final text = clipboard?.text;
+          if (text != null) {
+            _importUrlController.text = text;
+          }
+
+          _formKey.currentState!.validate();
+        }
+
         return SingleChildScrollView(
           child: Padding(
             padding: const EdgeInsets.all(10.0),
             child: Form(
+              key: _formKey,
               child: Column(
                 children: [
-                  TextField(
+                  TextFormField(
                     enabled: enabled,
                     controller: _importUrlController,
+                    validator: validate,
+                    onSaved: (value) {
+                      BlocProvider.of<RecipeBloc>(context).add(
+                        RecipeImported(value!),
+                      );
+                    },
+                    onEditingComplete: onSubmit,
                     decoration: InputDecoration(
                       hintText: translate("recipe_import.field"),
                       suffixIcon: IconButton(
                         tooltip: translate("recipe_import.clipboard"),
-                        onPressed: () async {
-                          final clipboard =
-                              await Clipboard.getData('text/plain');
-                          final text = clipboard?.text;
-                          if (text != null) _importUrlController.text = text;
-                        },
+                        onPressed: pasteClipboard,
                         icon: const Icon(Icons.content_copy_outlined),
                       ),
                     ),
@@ -69,13 +107,7 @@ class _RecipeImportFormState extends State<RecipeImportForm> {
                   Center(
                     child: enabled
                         ? OutlinedButton.icon(
-                            onPressed: () {
-                              if (enabled) {
-                                BlocProvider.of<RecipeBloc>(context).add(
-                                  RecipeImported(_importUrlController.text),
-                                );
-                              }
-                            },
+                            onPressed: onSubmit,
                             icon: const Icon(Icons.cloud_download_outlined),
                             label: Text(translate("recipe_import.button")),
                             style: OutlinedButton.styleFrom(