HashTagTextField class

A material design text field.

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.

If decoration is non-null (which is the default), the text field requires one of its ancestors to be a Material widget.

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

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.

{@tool snippet} This example shows how to create a HashTagTextField that will obscure input. The InputDecoration surrounds the field in a border using OutlineInputBorder and adds a label.

TextField(
  obscureText: true,
  decoration: InputDecoration(
    border: OutlineInputBorder(),
    labelText: 'Password',
  ),
)

{@end-tool}

Reading values

A common way to read a value from a TextField is to use the onSubmitted callback. This callback is applied to the text field's current value when the user finishes editing.

{@tool dartpad --template=stateful_widget_material}

This sample shows how to get a value from a TextField via the onSubmitted callback.

late TextEditingController _controller;

void initState() {
  super.initState();
  _controller = TextEditingController();
}

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

Widget build(BuildContext context) {
  return Scaffold(
    body: Center(
      child: TextField(
        controller: _controller,
        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: <Widget>[
                  TextButton(
                    onPressed: () { Navigator.pop(context); },
                    child: const Text('OK'),
                  ),
                ],
              );
            },
          );
        },
      ),
    ),
  );
}

{@end-tool}

For most applications the onSubmitted callback will be sufficient for reacting to user input.

The onEditingComplete callback also runs when the user finishes editing. It's different from onSubmitted because it has a default value which updates the text controller and yields the keyboard focus. Applications that require different behavior can override the default onEditingComplete callback.

Keep in mind you can also always read the current string from a TextField's TextEditingController using TextEditingController.text.

Handling emojis and other complex characters

It's important to always use characters when dealing with user input text that may contain complex characters. This will ensure that extended grapheme clusters and surrogate pairs are treated as single characters, as they appear to the user.

For example, when finding the length of some user input, use string.characters.length. Do NOT use string.length or even string.runes.length. For the complex character "👨‍👩‍👦", this appears to the user as a single character, and string.characters.length intuitively returns 1. On the other hand, string.length returns 8, and string.runes.length returns 5!

In the live Dartpad example above, try typing the emoji 👨‍👩‍👦 into the field and submitting. Because the example code measures the length with value.characters.length, the emoji is correctly counted as a single character.

Constructors

HashTagTextField({Key? key, TextEditingController? controller, TextStyle? decoratedStyle, VoidCallback? onDetectionFinished, ValueChanged<String>? onDetectionTyped, bool decorateAtSign = false, FocusNode? focusNode, InputDecoration? decoration = const InputDecoration(), TextInputType? keyboardType, TextInputAction? textInputAction, TextCapitalization textCapitalization = TextCapitalization.none, TextStyle? basicStyle, StrutStyle? strutStyle, TextAlign textAlign = TextAlign.start, TextAlignVertical? textAlignVertical, TextDirection? textDirection, bool readOnly = false, ToolbarOptions? toolbarOptions, bool? showCursor, bool autofocus = false, String obscuringCharacter = '•', bool obscureText = false, bool autocorrect = true, SmartDashesType? smartDashesType, SmartQuotesType? smartQuotesType, bool enableSuggestions = true, int? maxLines = 1, int? minLines, bool expands = false, int? maxLength, @Deprecated('Use maxLengthEnforcement parameter which provides more specific ' 'behavior related to the maxLength limit. ' 'This feature was deprecated after v1.25.0-5.0.pre.') bool maxLengthEnforced = true, MaxLengthEnforcement? maxLengthEnforcement, ValueChanged<String>? onChanged, VoidCallback? onEditingComplete, ValueChanged<String>? onSubmitted, AppPrivateCommandCallback? onAppPrivateCommand, List<TextInputFormatter>? inputFormatters, bool? enabled, double cursorWidth = 2.0, double? cursorHeight, Radius? cursorRadius, Color? cursorColor, BoxHeightStyle selectionHeightStyle = ui.BoxHeightStyle.tight, BoxWidthStyle selectionWidthStyle = ui.BoxWidthStyle.tight, Brightness? keyboardAppearance, EdgeInsets scrollPadding = const EdgeInsets.all(20.0), DragStartBehavior dragStartBehavior = DragStartBehavior.start, bool enableInteractiveSelection = true, TextSelectionControls? selectionControls, GestureTapCallback? onTap, MouseCursor? mouseCursor, InputCounterWidgetBuilder? buildCounter, ScrollController? scrollController, ScrollPhysics? scrollPhysics, Iterable<String>? autofillHints, String? restorationId}): Creates a Material Design text field.
const

Properties

autocorrect → bool: Whether to enable autocorrection.
final
autofillHints → Iterable<String>?: A list of strings that helps the autofill service identify the type of this text input.
final
autofocus → bool: Whether this text field should focus itself if nothing else is already focused.
final
basicStyle → TextStyle?: The style to use for the text being edited.
final
buildCounter → InputCounterWidgetBuilder?: Callback that generates a custom InputDecoration.counter widget.
final
controller → TextEditingController?: Controls the text being edited.
final
cursorColor → Color?: The color of the cursor.
final
cursorHeight → double?: How tall the cursor will be.
final
cursorRadius → Radius?: How rounded the corners of the cursor should be.
final
cursorWidth → double: How thick the cursor will be.
final
decorateAtSign → bool: Decides if text with at sign(@) decorated
final
decoratedStyle → TextStyle?: TextStyle of hashTag
final
decoration → InputDecoration?: The decoration to show around the text field.
final
dragStartBehavior → DragStartBehavior: Determines the way that drag start behavior is handled.
final
enabled → bool?: If false the text field is "disabled": it ignores taps and its decoration is rendered in grey.
final
enableInteractiveSelection → bool: Whether to enable user interface affordances for changing the text selection.
final
enableSuggestions → bool: Whether to show input suggestions as the user types.
final
expands → bool: Whether this widget's height will be sized to fill its parent.
final
focusNode → FocusNode?: Defines the keyboard focus for this widget.
final
hashCode → int: The hash code for this object.
no setterinherited
inputFormatters → List<TextInputFormatter>?: Optional input validation and formatting overrides.
final
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
keyboardAppearance → Brightness?: The appearance of the keyboard.
final
keyboardType → TextInputType: The type of keyboard to use for editing the text.
final
maxLength → int?: The maximum number of characters (Unicode scalar values) to allow in the text field.
final
maxLengthEnforced → bool: If maxLength is set, maxLengthEnforced indicates whether or not to enforce the limit, or merely provide a character counter and warning when maxLength is exceeded.
final
maxLengthEnforcement → MaxLengthEnforcement?: Determines how the maxLength limit should be enforced.
final
maxLines → int?: The maximum number of lines to show at one time, wrapping if necessary.
final
minLines → int?: The minimum number of lines to occupy when the content spans fewer lines.
final
mouseCursor → MouseCursor?: The cursor for a mouse pointer when it enters or is hovering over the widget.
final
obscureText → bool: Whether to hide the text being edited (e.g., for passwords).
final
obscuringCharacter → String: Character used for obscuring text if obscureText is true.
final
onAppPrivateCommand → AppPrivateCommandCallback?: This is used to receive a private command from the input method.
final
onChanged → ValueChanged<String>?: Called when the user initiates a change to the TextField's value: when they have inserted or deleted text.
final
onDetectionFinished → VoidCallback?: final
onDetectionTyped → ValueChanged<String>?: final
onEditingComplete → VoidCallback?: Called when the user submits editable content (e.g., user presses the "done" button on the keyboard).
final
onSubmitted → ValueChanged<String>?: Called when the user indicates that they are done editing the text in the field.
final
onTap → GestureTapCallback?: Called for the first tap in a series of taps.
final
readOnly → bool: Whether the text can be changed.
final
restorationId → String?: Restoration ID to save and restore the state of the text field.
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
scrollController → ScrollController?: The ScrollController to use when vertically scrolling the input.
final
scrollPadding → EdgeInsets: Configures padding to edges surrounding a Scrollable when the Textfield scrolls into view.
final
scrollPhysics → ScrollPhysics?: The ScrollPhysics to use when vertically scrolling the input.
final
selectionControls → TextSelectionControls?: Optional delegate for building the text selection handles.
final
selectionEnabled → bool: Same as enableInteractiveSelection.
no setter
selectionHeightStyle → BoxHeightStyle: Controls how tall the selection highlight boxes are computed to be.
final
selectionWidthStyle → BoxWidthStyle: Controls how wide the selection highlight boxes are computed to be.
final
showCursor → bool?: Whether to show cursor.
final
smartDashesType → SmartDashesType: Whether to allow the platform to automatically format dashes.
final
smartQuotesType → SmartQuotesType: Whether to allow the platform to automatically format quotes.
final
strutStyle → StrutStyle?: The strut style used for the vertical layout.
final
textAlign → TextAlign: How the text should be aligned horizontally.
final
textAlignVertical → TextAlignVertical?: How the text should be aligned vertically.
final
textCapitalization → TextCapitalization: Configures how the platform keyboard will select an uppercase or lowercase keyboard.
final
textDirection → TextDirection?: The directionality of the text.
final
textInputAction → TextInputAction?: The type of action button to use for the keyboard.
final
toolbarOptions → ToolbarOptions: Configuration of toolbar options.
final

Methods

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → _HashTagTextFieldState: Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
override
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode: Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String: A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a one-line detailed description of the object.
inherited
toStringShort() → String: A short, textual description of this widget.
inherited

Operators

operator ==(Object other) → bool: The equality operator.
inherited

Constants

noMaxLength → const int: If maxLength is set to this value, only the "current input length" part of the character counter is shown.