handleFocusChange method
Implementation
void handleFocusChange(int index) {
FocusNode? focusNode = _focusNodes[index];
TextEditingController? controller = _textControllers[index];
if (focusNode == null || controller == null) return;
if (focusNode.hasFocus) {
controller.selection = TextSelection.fromPosition(
TextPosition(offset: controller.text.length));
}
}