Reland "[text_input] introduce TextInputControl" (flutter#113758)

AUTHORS

@@ -77,6 +77,7 @@ Hidenori Matsubayashi <Hidenori.Matsubayashi@sony.com>
 Perqin Xie <perqinxie@gmail.com>
 Seongyun Kim <helloworld@cau.ac.kr>
 Ludwik Trammer <ludwik@gmail.com>
+J-P Nurmi <jpnurmi@gmail.com>
 Marian Triebe <m.triebe@live.de>
 Alexis Rouillard <contact@arouillard.fr>
 Mirko Mucaria <skogsfrae@gmail.com>

examples/api/lib/services/text_input/text_input_control.0.dart

@@ -0,0 +1,167 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flutter code sample for TextInputControl
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+void main() => runApp(const MyApp());
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      home: MyStatefulWidget(),
+   );
+  }
+}
+
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({super.key});
+
+  @override
+  MyStatefulWidgetState createState() => MyStatefulWidgetState();
+}
+
+class MyStatefulWidgetState extends State<MyStatefulWidget> {
+  final TextEditingController _controller = TextEditingController();
+  final FocusNode _focusNode = FocusNode();
+
+  @override
+  void dispose() {
+    super.dispose();
+    _controller.dispose();
+    _focusNode.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: TextField(
+          autofocus: true,
+          controller: _controller,
+          focusNode: _focusNode,
+          decoration: InputDecoration(
+            suffix: IconButton(
+              icon: const Icon(Icons.clear),
+              tooltip: 'Clear and unfocus',
+              onPressed: () {
+                _controller.clear();
+                _focusNode.unfocus();
+              },
+            ),
+          ),
+        ),
+      ),
+      bottomSheet: const MyVirtualKeyboard(),
+    );
+  }
+}
+
+class MyVirtualKeyboard extends StatefulWidget {
+  const MyVirtualKeyboard({super.key});
+
+  @override
+  MyVirtualKeyboardState createState() => MyVirtualKeyboardState();
+}
+
+class MyVirtualKeyboardState extends State<MyVirtualKeyboard> {
+  final MyTextInputControl _inputControl = MyTextInputControl();
+
+  @override
+  void initState() {
+    super.initState();
+    _inputControl.register();
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    _inputControl.unregister();
+  }
+
+  void _handleKeyPress(String key) {
+    _inputControl.processUserInput(key);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ValueListenableBuilder<bool>(
+      valueListenable: _inputControl.visible,
+      builder: (_, bool visible, __) {
+        return Visibility(
+          visible: visible,
+          child: FocusScope(
+            canRequestFocus: false,
+            child: TextFieldTapRegion(
+              child: Row(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: <Widget>[
+                  for (final String key in <String>['A', 'B', 'C'])
+                    ElevatedButton(
+                      child: Text(key),
+                      onPressed: () => _handleKeyPress(key),
+                    ),
+                ],
+              ),
+            ),
+          ),
+        );
+      },
+    );
+  }
+}
+
+class MyTextInputControl with TextInputControl {
+  TextEditingValue _editingState = TextEditingValue.empty;
+  final ValueNotifier<bool> _visible = ValueNotifier<bool>(false);
+
+  /// The input control's visibility state for updating the visual presentation.
+  ValueListenable<bool> get visible => _visible;
+
+  /// Register the input control.
+  void register() => TextInput.setInputControl(this);
+
+  /// Restore the original platform input control.
+  void unregister() => TextInput.restorePlatformInputControl();
+
+  @override
+  void show() => _visible.value = true;
+
+  @override
+  void hide() => _visible.value = false;
+
+  @override
+  void setEditingState(TextEditingValue value) => _editingState = value;
+
+  /// Process user input.
+  ///
+  /// Updates the internal editing state by inserting the input text,
+  /// and by replacing the current selection if any.
+  void processUserInput(String input) {
+    _editingState = _editingState.copyWith(
+      text: _insertText(input),
+      selection: _replaceSelection(input),
+    );
+
+    // Request the attached client to update accordingly.
+    TextInput.updateEditingValue(_editingState);
+  }
+
+  String _insertText(String input) {
+    final String text = _editingState.text;
+    final TextSelection selection = _editingState.selection;
+    return text.replaceRange(selection.start, selection.end, input);
+  }
+
+  TextSelection _replaceSelection(String input) {
+    final TextSelection selection = _editingState.selection;
+    return TextSelection.collapsed(offset: selection.start + input.length);
+  }
+}

examples/api/test/services/text_input/text_input_control.0_test.dart

@@ -0,0 +1,40 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_api_samples/services/text_input/text_input_control.0.dart'
+    as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('Enter text using the VKB', (WidgetTester tester) async {
+    await tester.pumpWidget(const example.MyApp());
+    await tester.pumpAndSettle();
+
+    await tester.tap(find.descendant(
+      of: find.byType(example.MyVirtualKeyboard),
+      matching: find.widgetWithText(ElevatedButton, 'A'),
+    ));
+    await tester.pumpAndSettle();
+    expect(find.widgetWithText(TextField, 'A'), findsOneWidget);
+
+    await tester.tap(find.descendant(
+      of: find.byType(example.MyVirtualKeyboard),
+      matching: find.widgetWithText(ElevatedButton, 'B'),
+    ));
+    await tester.pumpAndSettle();
+    expect(find.widgetWithText(TextField, 'AB'), findsOneWidget);
+
+    await tester.sendKeyEvent(LogicalKeyboardKey.arrowLeft);
+    await tester.pumpAndSettle();
+
+    await tester.tap(find.descendant(
+      of: find.byType(example.MyVirtualKeyboard),
+      matching: find.widgetWithText(ElevatedButton, 'C'),
+    ));
+    await tester.pumpAndSettle();
+    expect(find.widgetWithText(TextField, 'ACB'), findsOneWidget);
+  });
+}