TextFormField constructor Null safety

Implementation

TextFormField({
  super.key,
  this.controller,
  String? initialValue,
  FocusNode? focusNode,
  InputDecoration? decoration = const InputDecoration(),
  TextInputType? keyboardType,
  TextCapitalization textCapitalization = TextCapitalization.none,
  TextInputAction? textInputAction,
  TextStyle? style,
  StrutStyle? strutStyle,
  TextDirection? textDirection,
  TextAlign textAlign = TextAlign.start,
  TextAlignVertical? textAlignVertical,
  bool autofocus = false,
  bool readOnly = false,
  ToolbarOptions? toolbarOptions,
  bool? showCursor,
  String obscuringCharacter = '•',
  bool obscureText = false,
  bool autocorrect = true,
  SmartDashesType? smartDashesType,
  SmartQuotesType? smartQuotesType,
  bool enableSuggestions = true,
  MaxLengthEnforcement? maxLengthEnforcement,
  int? maxLines = 1,
  int? minLines,
  bool expands = false,
  int? maxLength,
  ValueChanged<String>? onChanged,
  GestureTapCallback? onTap,
  TapRegionCallback? onTapOutside,
  VoidCallback? onEditingComplete,
  ValueChanged<String>? onFieldSubmitted,
  super.onSaved,
  super.validator,
  List<TextInputFormatter>? inputFormatters,
  bool? enabled,
  double cursorWidth = 2.0,
  double? cursorHeight,
  Radius? cursorRadius,
  Color? cursorColor,
  Brightness? keyboardAppearance,
  EdgeInsets scrollPadding = const EdgeInsets.all(20.0),
  bool? enableInteractiveSelection,
  TextSelectionControls? selectionControls,
  InputCounterWidgetBuilder? buildCounter,
  ScrollPhysics? scrollPhysics,
  Iterable<String>? autofillHints,
  AutovalidateMode? autovalidateMode,
  ScrollController? scrollController,
  super.restorationId,
  bool enableIMEPersonalizedLearning = true,
  MouseCursor? mouseCursor,
}) : assert(initialValue == null || controller == null),
     assert(textAlign != null),
     assert(autofocus != null),
     assert(readOnly != null),
     assert(obscuringCharacter != null && obscuringCharacter.length == 1),
     assert(obscureText != null),
     assert(autocorrect != null),
     assert(enableSuggestions != null),
     assert(scrollPadding != null),
     assert(maxLines == null || maxLines > 0),
     assert(minLines == null || minLines > 0),
     assert(
       (maxLines == null) || (minLines == null) || (maxLines >= minLines),
       "minLines can't be greater than maxLines",
     ),
     assert(expands != null),
     assert(
       !expands || (maxLines == null && minLines == null),
       'minLines and maxLines must be null when expands is true.',
     ),
     assert(!obscureText || maxLines == 1, 'Obscured fields cannot be multiline.'),
     assert(maxLength == null || maxLength == TextField.noMaxLength || maxLength > 0),
     assert(enableIMEPersonalizedLearning != null),
     super(
       initialValue: controller != null ? controller.text : (initialValue ?? ''),
       enabled: enabled ?? decoration?.enabled ?? true,
       autovalidateMode: autovalidateMode ?? AutovalidateMode.disabled,
       builder: (FormFieldState<String> field) {
         final _TextFormFieldState state = field as _TextFormFieldState;
         final InputDecoration effectiveDecoration = (decoration ?? const InputDecoration())
             .applyDefaults(Theme.of(field.context).inputDecorationTheme);
         void onChangedHandler(String value) {
           field.didChange(value);
           if (onChanged != null) {
             onChanged(value);
           }
         }
         return UnmanagedRestorationScope(
           bucket: field.bucket,
           child: TextField(
             restorationId: restorationId,
             controller: state._effectiveController,
             focusNode: focusNode,
             decoration: effectiveDecoration.copyWith(errorText: field.errorText),
             keyboardType: keyboardType,
             textInputAction: textInputAction,
             style: style,
             strutStyle: strutStyle,
             textAlign: textAlign,
             textAlignVertical: textAlignVertical,
             textDirection: textDirection,
             textCapitalization: textCapitalization,
             autofocus: autofocus,
             toolbarOptions: toolbarOptions,
             readOnly: readOnly,
             showCursor: showCursor,
             obscuringCharacter: obscuringCharacter,
             obscureText: obscureText,
             autocorrect: autocorrect,
             smartDashesType: smartDashesType ?? (obscureText ? SmartDashesType.disabled : SmartDashesType.enabled),
             smartQuotesType: smartQuotesType ?? (obscureText ? SmartQuotesType.disabled : SmartQuotesType.enabled),
             enableSuggestions: enableSuggestions,
             maxLengthEnforcement: maxLengthEnforcement,
             maxLines: maxLines,
             minLines: minLines,
             expands: expands,
             maxLength: maxLength,
             onChanged: onChangedHandler,
             onTap: onTap,
             onTapOutside: onTapOutside,
             onEditingComplete: onEditingComplete,
             onSubmitted: onFieldSubmitted,
             inputFormatters: inputFormatters,
             enabled: enabled ?? decoration?.enabled ?? true,
             cursorWidth: cursorWidth,
             cursorHeight: cursorHeight,
             cursorRadius: cursorRadius,
             cursorColor: cursorColor,
             scrollPadding: scrollPadding,
             scrollPhysics: scrollPhysics,
             keyboardAppearance: keyboardAppearance,
             enableInteractiveSelection: enableInteractiveSelection ?? (!obscureText || !readOnly),
             selectionControls: selectionControls,
             buildCounter: buildCounter,
             autofillHints: autofillHints,
             scrollController: scrollController,
             enableIMEPersonalizedLearning: enableIMEPersonalizedLearning,
             mouseCursor: mouseCursor,
           ),
         );
       },
     );