selectWordEdge method Null safety

void selectWordEdge(
  1. {required SelectionChangedCause cause}
)

Move the selection to the beginning or end of a word.

This method is mainly used to translate user inputs in global positions into a TextSelection. When used in conjunction with a EditableText, the selection change is fed back into TextEditingController.selection.

If you have a TextEditingController, it's generally easier to programmatically manipulate its value or selection directly.

Implementation

void selectWordEdge({ required SelectionChangedCause cause }) {
  assert(cause != null);
  _computeTextMetricsIfNeeded();
  assert(_lastTapDownPosition != null);
  final TextPosition position = _textPainter.getPositionForOffset(globalToLocal(_lastTapDownPosition! - _paintOffset));
  final TextRange word = _textPainter.getWordBoundary(position);
  late TextSelection newSelection;
  if (position.offset - word.start <= 1) {
    newSelection = TextSelection.collapsed(offset: word.start, affinity: TextAffinity.downstream);
  } else {
    newSelection = TextSelection.collapsed(offset: word.end, affinity: TextAffinity.upstream);
  }
  _setSelection(newSelection, cause);
}