strt method

void strt()

Implementation

void strt() {
  double end = isFrontStart ? (dragPosition > 180 ? 360 : 0) : 180;
  animation = Tween<double>(
    begin: dragPosition,
    end: end,
  ).animate(animationController);
  if (animationController.isAnimating) {
    return;
  } else {
    animationController.forward(from: 0);
  }
  isFrontStart = !(dragPosition <= 90 || dragPosition >= 270);
}