TextField constructor
Creates a Material Design text field.
If decoration
is non-null (which is the default), the text field requires
one of its ancestors to be a Material widget.
To remove the decoration entirely (including the extra padding introduced
by the decoration to save space for the labels), set the decoration
to
null.
The maxLines
property can be set to null to remove the restriction on
the number of lines. By default, it is one, meaning this is a single-line
text field. maxLines
must not be zero.
The maxLength
property is set to null by default, which means the
number of characters allowed in the text field is not restricted. If
maxLength
is set, a character counter will be displayed below the
field, showing how many characters have been entered and how many are
allowed unless the value is set to noMaxLength in which case only the
current length is displayed.
After maxLength
characters have been input, additional input
is ignored, unless maxLengthEnforced
is set to false. The TextField
enforces the length with a LengthLimitingTextInputFormatter, which is
evaluated after the supplied inputFormatters
, if any. The maxLength
value must be either null or greater than zero.
If maxLengthEnforced
is set to false, then more than maxLength
characters may be entered, and the error counter and divider will
switch to the decoration.errorStyle
when the limit is exceeded.
The textAlign
, autofocus
, obscureText
, autocorrect
,
maxLengthEnforced
, scrollPadding
, maxLines
, maxLength
,
and enableInteractiveSelection
arguments must not be null.
See also:
maxLength
, which discusses the precise meaning of "number of characters" and how it may differ from the intuitive meaning.
Implementation
const TextField({
Key key,
this.controller,
this.focusNode,
this.decoration = const InputDecoration(),
TextInputType keyboardType,
this.textInputAction,
this.textCapitalization = TextCapitalization.none,
this.style,
this.textAlign = TextAlign.start,
this.textDirection,
this.autofocus = false,
this.obscureText = false,
this.autocorrect = true,
this.maxLines = 1,
this.maxLength,
this.maxLengthEnforced = true,
this.onChanged,
this.onEditingComplete,
this.onSubmitted,
this.inputFormatters,
this.enabled,
this.cursorWidth = 2.0,
this.cursorRadius,
this.cursorColor,
this.keyboardAppearance,
this.scrollPadding = const EdgeInsets.all(20.0),
this.enableInteractiveSelection = true,
this.onTap,
}) : assert(textAlign != null),
assert(autofocus != null),
assert(obscureText != null),
assert(autocorrect != null),
assert(maxLengthEnforced != null),
assert(scrollPadding != null),
assert(maxLines == null || maxLines > 0),
assert(maxLength == null || maxLength > 0),
keyboardType = keyboardType ?? (maxLines == 1 ? TextInputType.text : TextInputType.multiline),
assert(enableInteractiveSelection != null),
super(key: key);