README.md

TextField

A text field lets the user enter text, either with hardware keyboard or with an onscreen keyboard.

• The text field calls the onChanged callback whenever the user changes the text in the field. If the user indicates that they are done typing in the field (e.g., by pressing a button on the soft keyboard), the text field calls the onSubmitted callback.

• To control the text that is displayed in the text field, use the controller. For example, to set the initial value of the text field, use a controller that already contains some text. The controller can also control the selection and composing region (and to observe changes to the text, selection, and composing region).

• By default, a text field has a decoration that draws a divider below the text field. You can use the decoration property to control the decoration, for example by adding a label or an icon. If you set the decoration property to null, the decoration will be removed entirely, including the extra padding introduced by the decoration to save space for the labels.

• To integrate the TextField into a Form with other FormField widgets, consider using TextFormField.

• When the widget has focus, it will prevent itself from disposing via its underlying EditableText's AutomaticKeepAliveClientMixin.wantKeepAlive in order to avoid losing the selection. Removing the focus will allow it to be disposed.

• Remember to call TextEditingController.dispose of the TextEditingController when it is no longer needed. This will ensure we discard any resources used by the object.

Example

class ExTextField extends StatefulWidget {
  const ExTextField({super.key});

  @override
  State<ExTextField> createState() => _ExTextFieldState();
}

class _ExTextFieldState extends State<ExTextField> {
  late TextEditingController _controller;

  @override
  void initState() {
    super.initState();
    _controller = TextEditingController();
    _controller.text = "123";
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: TextField(
          controller: _controller,
          obscureText: false,
          autofocus: true,
          cursorWidth: 1,
          decoration: const InputDecoration(
            border: OutlineInputBorder(),
            labelText: 'Password',
            prefixIcon: Icon(Icons.key),
          ),
          onSubmitted: (String value) async {
            await showDialog<void>(
              context: context,
              builder: (BuildContext context) {
                return AlertDialog(
                  title: const Text('Thanks!'),
                  content: Text(
                      'You typed "$value", which has length ${value.characters.length}.'),
                  actions: [
                    TextButton(
                      onPressed: () {
                        Navigator.pop(context);
                      },
                      child: const Text('OK'),
                    ),
                  ],
                );
              },
            );
          },
        ),
      ),
    );
  }
}

Change Focus

class ExTextFieldFocus extends StatefulWidget {
  const ExTextFieldFocus({super.key});

  @override
  State<ExTextFieldFocus> createState() => _ExTextFieldFocusState();
}

class _ExTextFieldFocusState extends State<ExTextFieldFocus> {
  FocusNode focusNode1 = FocusNode();
  FocusNode focusNode2 = FocusNode();
  FocusScopeNode? focusScopeNode;

  @override
  void initState() {
    super.initState();
    focusNode1.addListener(() {
      print(focusNode1.hasFocus);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.all(16.0),
      child: Column(
        children: [
          TextField(
            autofocus: true,
            focusNode: focusNode1,
            decoration: InputDecoration(labelText: "input1"),
          ),
          TextField(
            focusNode: focusNode2,
            decoration: InputDecoration(labelText: "input2"),
          ),
          Builder(
            builder: (BuildContext ctx) {
              return Column(
                children: [
                  ElevatedButton(
                    child: Text("Focus Input2"),
                    onPressed: () {
                      //change focus from TextField1 to TextField2
                      // method1:
                      FocusScope.of(context).requestFocus(focusNode2);
                      // method2:
                      // focusScopeNode ??= FocusScope.of(context);
                      // focusScopeNode?.requestFocus(focusNode2);
                    },
                  ),
                  ElevatedButton(
                    child: Text("hide keyboard"),
                    onPressed: () {
                      focusNode1.unfocus();
                      focusNode2.unfocus();
                    },
                  ),
                ],
              );
            },
          ),
        ],
      ),
    );
  }
}