buildTextSpan method Null safety

TextSpan buildTextSpan(
  1. {required BuildContext context,
  2. TextStyle? style,
  3. required bool withComposing}
)

Builds TextSpan from current editing value.

By default makes text in composing range appear as underlined. Descendants can override this method to customize appearance of text.

Implementation

TextSpan buildTextSpan({required BuildContext context, TextStyle? style , required bool withComposing}) {
  assert(!value.composing.isValid || !withComposing || value.isComposingRangeValid);
  // If the composing range is out of range for the current text, ignore it to
  // preserve the tree integrity, otherwise in release mode a RangeError will
  // be thrown and this EditableText will be built with a broken subtree.
  if (!value.isComposingRangeValid || !withComposing) {
    return TextSpan(style: style, text: text);
  }
  final TextStyle composingStyle = style?.merge(const TextStyle(decoration: TextDecoration.underline))
      ?? const TextStyle(decoration: TextDecoration.underline);
  return TextSpan(
    style: style,
    children: <TextSpan>[
      TextSpan(text: value.composing.textBefore(value.text)),
      TextSpan(
        style: composingStyle,
        text: value.composing.textInside(value.text),
      ),
      TextSpan(text: value.composing.textAfter(value.text)),
    ],
  );
}