[Swift-iOS]Dragging down view using UIPanGestureRecognizer, not stretching

I'm trying to drag down a specific view to make the height go longer than before using UIPanGestureRecognizer. However, it keeps on going back to the normal size that i had initially programmed. The view that i'm trying to stretch keeps on shaking and goes back to the initial height. Any guesses why?

    let CalendarDrag = UIPanGestureRecognizer(target: self, action: #selector(didDragCalendar))
    lineView.isUserInteractionEnabled = true
    lineView.addGestureRecognizer(CalendarDrag)

}


@objc func didDragCalendar(sender: UIPanGestureRecognizer) {
    let velocity = sender.velocity(in: self.view) //속도
    let translation = sender.translation(in: self.view) //위치
    let height = self.topView.frame.maxY
    
    if sender.state == .ended{
        if velocity.y>0{
            calendar.scope = .month
            print("down")
        }else{
            calendar.scope = .week
            print("up")
        }
    }else{
        if height <= height+translation.y && height+translation.y <= height+230{
            self.topView.frame = CGRect(x: 0, y: 0, width: self.topView.frame.width, height: height+translation.y)
            UIView.animate(withDuration: 0, animations: {
                self.view.layoutIfNeeded()
                sender.setTranslation(CGPoint.zero, in: self.view)
            })
        }
    }
}

For more information, I'm right now trying to make FSCalendar to show in "month" and "week" view according to the UIPanGesture that user make.

You are changing the frame height of your view. Don't do that.

Have an instance var to a height constraint, and change the constant value for that constraint. Then when you call layoutIfNeeded() from your animation, the constraint will change your height for you.