selectWordEdge method

@override void selectWordEdge(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

@override
void selectWordEdge(SelectionChangedCause cause) {
  assert(_lastTapDownPosition != null);
  final position = getPositionForOffset(_lastTapDownPosition!);
  final child = childAtPosition(position);
  final nodeOffset = child.container.offset;
  final localPosition = TextPosition(
    offset: position.offset - nodeOffset,
    affinity: position.affinity,
  );
  final localWord = child.getWordBoundary(localPosition);
  final word = TextRange(
    start: localWord.start + nodeOffset,
    end: localWord.end + nodeOffset,
  );
  if (position.offset - word.start <= 1 && word.end != position.offset) {
    _handleSelectionChange(
      TextSelection.collapsed(offset: word.start),
      cause,
    );
  } else {
    _handleSelectionChange(
      TextSelection.collapsed(
          offset: word.end, affinity: TextAffinity.upstream),
      cause,
    );
  }
}