Fix external controller disposal causing scroll errors

example/lib/example_scroll_form.dart

@@ -0,0 +1,148 @@
+import 'package:chips_input_autocomplete/chips_input_autocomplete.dart';
+import 'package:flutter/material.dart';
+
+/// Example demonstrating the fix for the scroll error when using an external controller.
+///
+/// This example creates a scrollable form with ChipsInputAutocomplete widgets.
+/// When the widget scrolls out of view and back, it should continue to work
+/// without errors because the external controller is not disposed.
+class ChipsInputExampleScrollForm extends StatefulWidget {
+  const ChipsInputExampleScrollForm({super.key});
+
+  @override
+  State<ChipsInputExampleScrollForm> createState() =>
+      _ChipsInputExampleScrollFormState();
+}
+
+class _ChipsInputExampleScrollFormState
+    extends State<ChipsInputExampleScrollForm> {
+  static const double _scrollSpacing = 300.0;
+
+  final _formKey = GlobalKey<FormState>();
+  final _companyNameController = TextEditingController();
+  final _industryChipController = ChipsAutocompleteController();
+  final _companyNameController2 = TextEditingController();
+
+  final List<String> industryValues = [
+    'Technology',
+    'Healthcare',
+    'Finance',
+    'Education',
+    'Manufacturing',
+    'Retail',
+    'Real Estate',
+    'Entertainment',
+    'Transportation',
+    'Agriculture'
+  ];
+
+  @override
+  void dispose() {
+    _companyNameController.dispose();
+    _industryChipController.dispose();
+    _companyNameController2.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Card(
+      child: Padding(
+        padding: const EdgeInsets.all(8.0),
+        child: ConstrainedBox(
+          constraints: const BoxConstraints(maxWidth: 500),
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Align(
+                alignment: Alignment.centerLeft,
+                child: Padding(
+                  padding: const EdgeInsets.only(bottom: 16.0),
+                  child: Text(
+                    'Scrollable Form Example',
+                    style: Theme.of(context).textTheme.titleLarge,
+                  ),
+                ),
+              ),
+              Text(
+                'This demonstrates the fix for the scroll error. '
+                'The ChipsInputAutocomplete widget uses an external controller '
+                'and can be scrolled without errors.',
+                style: Theme.of(context).textTheme.bodyMedium,
+              ),
+              const SizedBox(height: 16),
+              Expanded(
+                child: Form(
+                  key: _formKey,
+                  child: ListView(
+                    shrinkWrap: true,
+                    children: [
+                      // First TextField
+                      TextField(
+                        controller: _companyNameController,
+                        decoration: const InputDecoration(
+                          labelText: 'Company Name',
+                          hintText: 'Enter company name',
+                          border: OutlineInputBorder(),
+                        ),
+                      ),
+                      const SizedBox(height: _scrollSpacing), // Add spacing to force scrolling
+
+                      // ChipsInputAutocomplete with external controller
+                      const Text(
+                        'Select Industries:',
+                        style: TextStyle(fontWeight: FontWeight.bold),
+                      ),
+                      const SizedBox(height: 8),
+                      ChipsInputAutocomplete(
+                        options: industryValues,
+                        createCharacter: ',',
+                        controller: _industryChipController,
+                        widgetContainerDecoration: BoxDecoration(
+                          border: Border.all(color: Colors.grey),
+                          borderRadius: BorderRadius.circular(10),
+                        ),
+                        decorationTextField: const InputDecoration(
+                          hintText: 'Type to search industries...',
+                        ),
+                      ),
+                      const SizedBox(height: _scrollSpacing), // Add spacing to force scrolling
+
+                      // Second TextField
+                      TextField(
+                        controller: _companyNameController2,
+                        decoration: const InputDecoration(
+                          labelText: 'Additional Info',
+                          hintText: 'Enter additional information',
+                          border: OutlineInputBorder(),
+                        ),
+                      ),
+                      const SizedBox(height: 20),
+
+                      // Submit Button
+                      ElevatedButton(
+                        onPressed: () {
+                          if (_formKey.currentState!.validate()) {
+                            ScaffoldMessenger.of(context).showSnackBar(
+                              SnackBar(
+                                content: Text(
+                                  'Company: ${_companyNameController.text}, '
+                                  'Industries: ${_industryChipController.chips.join(', ')}',
+                                ),
+                              ),
+                            );
+                          }
+                        },
+                        child: const Text('Submit'),
+                      ),
+                    ],
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

example/lib/main.dart

@@ -11,6 +11,7 @@ import 'package:chips_input_autocomplete_example/example_insert_on_select.dart';
 import 'package:chips_input_autocomplete_example/example_only_options.dart';
 import 'package:chips_input_autocomplete_example/constants.dart';
 import 'package:chips_input_autocomplete_example/example_options_async_basic.dart';
+import 'package:chips_input_autocomplete_example/example_scroll_form.dart';
 import 'package:chips_input_autocomplete_example/example_secondary_theme.dart';
 import 'package:flutter/material.dart';
 import 'package:chips_input_autocomplete/chips_input_autocomplete.dart';
@@ -241,6 +242,13 @@ class _HomePageState extends State<HomePage> {
                 height: 16,
               ),
               const ChipsInputExampleForm(),
+              const SizedBox(
+                height: 16,
+              ),
+              const SizedBox(
+                height: 400,
+                child: ChipsInputExampleScrollForm(),
+              ),
             ],
           ),
         ),

lib/src/chips_input_autocomplete.dart

@@ -243,11 +243,14 @@ class ChipsInputAutocompleteState extends State<ChipsInputAutocomplete> {
   late final ChipsAutocompleteController _chipsAutocompleteController;
   late final GlobalKey<FormFieldState<List<String>>> _formFieldKey;
   late final FocusNode _focusNode;
+  late final bool _controllerCreatedInternally;
+  late final bool _focusNodeCreatedInternally;
   String? _errorText;
 
   @override
   void initState() {
     super.initState();
+    _controllerCreatedInternally = widget.controller == null;
     _chipsAutocompleteController =
         widget.controller ?? ChipsAutocompleteController();
     if (widget.options != null) {
@@ -262,13 +265,20 @@ class ChipsInputAutocompleteState extends State<ChipsInputAutocomplete> {
     _formFieldKey =
         widget.formFieldKey ?? GlobalKey<FormFieldState<List<String>>>();
     _chipsAutocompleteController.formFieldKey = _formFieldKey;
+    _focusNodeCreatedInternally = widget.focusNode == null;
     _focusNode = widget.focusNode ?? FocusNode();
   }
 
   @override
   void dispose() {
-    _chipsAutocompleteController.dispose();
-    _focusNode.dispose();
+    // Only dispose the controller if we created it internally
+    if (_controllerCreatedInternally) {
+      _chipsAutocompleteController.dispose();
+    }
+    // Only dispose the focus node if we created it internally
+    if (_focusNodeCreatedInternally) {
+      _focusNode.dispose();
+    }
     super.dispose();
   }
 

test/chips_input_autocomplete_test.dart

@@ -48,4 +48,137 @@ void main() {
         reason:
             'Chip not added \nchipsAutocompleteController.chips: ${chipsAutocompleteController.chips} \nchipsAutocompleteController.text: ${chipsAutocompleteController.text}');
   });
+
+  // Test 3: Controller disposal - external controller should not be disposed
+  testWidgets(
+      'External controller should not be disposed when widget is disposed',
+      (WidgetTester tester) async {
+    final externalController = ChipsAutocompleteController();
+
+    // Verify controller is not disposed initially
+    expect(() => externalController.chips, returnsNormally);
+
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        body: ListView(
+          children: [
+            SizedBox(height: 1000), // Force scrolling
+            ChipsInputAutocomplete(
+              controller: externalController,
+              options: const ['option1', 'option2'],
+            ),
+            SizedBox(height: 1000),
+          ],
+        ),
+      ),
+    ));
+
+    // Verify controller works
+    expect(() => externalController.chips, returnsNormally);
+
+    // Remove the widget by replacing with a different widget
+    await tester.pumpWidget(const MaterialApp(
+      home: Scaffold(
+        body: Text('Replaced'),
+      ),
+    ));
+
+    // Verify the external controller is still usable after widget disposal
+    expect(() => externalController.chips, returnsNormally);
+    expect(() => externalController.addChip('test'), returnsNormally);
+    expect(externalController.chips.contains('test'), true);
+
+    // Clean up
+    externalController.dispose();
+  });
+
+  // Test 4: FocusNode disposal - external FocusNode should not be disposed
+  testWidgets(
+      'External FocusNode should not be disposed when widget is disposed',
+      (WidgetTester tester) async {
+    final externalFocusNode = FocusNode();
+
+    // Verify FocusNode is not disposed initially
+    expect(externalFocusNode.hasFocus, isFalse);
+
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        body: ChipsInputAutocomplete(
+          focusNode: externalFocusNode,
+          options: const ['option1', 'option2'],
+        ),
+      ),
+    ));
+
+    // Remove the widget
+    await tester.pumpWidget(const MaterialApp(
+      home: Scaffold(
+        body: Text('Replaced'),
+      ),
+    ));
+
+    // Verify the external FocusNode is still usable after widget disposal
+    expect(() => externalFocusNode.hasFocus, returnsNormally);
+
+    // Clean up
+    externalFocusNode.dispose();
+  });
+
+  // Test 5: Scroll test - widget with external controller in scrollable list
+  testWidgets(
+      'Widget with external controller should work correctly in scrollable list',
+      (WidgetTester tester) async {
+    final controller = ChipsAutocompleteController();
+
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        body: ListView(
+          children: [
+            const TextField(
+              decoration: InputDecoration(hintText: 'Field 1'),
+            ),
+            const SizedBox(height: 500),
+            ChipsInputAutocomplete(
+              controller: controller,
+              options: const ['Apple', 'Banana', 'Cherry'],
+              widgetContainerDecoration: BoxDecoration(
+                border: Border.all(color: Colors.grey),
+              ),
+            ),
+            const SizedBox(height: 500),
+            const TextField(
+              decoration: InputDecoration(hintText: 'Field 2'),
+            ),
+          ],
+        ),
+      ),
+    ));
+
+    // Add a chip
+    controller.addChip('Apple');
+    await tester.pump();
+
+    expect(controller.chips.contains('Apple'), true);
+
+    // Scroll down so the widget goes out of view
+    await tester.drag(find.byType(ListView), const Offset(0, -600));
+    await tester.pumpAndSettle();
+
+    // Verify controller is still working
+    expect(() => controller.chips, returnsNormally);
+    expect(controller.chips.contains('Apple'), true);
+
+    // Scroll back up
+    await tester.drag(find.byType(ListView), const Offset(0, 600));
+    await tester.pumpAndSettle();
+
+    // Verify widget is still functional
+    expect(controller.chips.contains('Apple'), true);
+    controller.addChip('Banana');
+    await tester.pump();
+    expect(controller.chips.length, 2);
+
+    // Clean up
+    controller.dispose();
+  });
 }