previousStroke method Null safety

void previousStroke()

Implementation

void previousStroke() {
  if (!_isQuizzing) {
    if (currentStroke != 0) {
      _setCurrentStroke(currentStroke - 1);
    }

    if (_isAnimating) {
      _strokeAnimationController.reset();
      _strokeAnimationController.forward();
    }

    notifyListeners();
  }
}