Swift UIView zPosition issue, views overlap on other views - swift

Question

I am writing a calendar view, I added three other views to its super view, so the calendar view should be on the topper layer, it looks fine on the simulator
but later on, I found that I can't click the button, then I checked the view hierarchy, found that the other three views overlap on the calendar, it is so weird as the 3d preview and view on the simulator are different
Here is the code of UI Part
func updateUI() {
if calendarView != nil {
self.view.addSubview(calendarView!)
self.calendarView!.frame.origin = calendarViewPosition!
self.calendarView!.layer.zPosition = 5
self.calendarView!.layer.cornerRadius = self.setting.itemCardCornerRadius
self.calendarView!.layer.masksToBounds = true
self.calendarView!.setViewShadow()
UIView.animate(withDuration: 0.8, delay: 0, options: .curveEaseOut, animations: {
self.calendarView!.frame.origin.y += 50
}) { _ in
var newCalendarPageCordiateYDifference: CGFloat = 10
var newCalendarPageSizeDifference: CGFloat = 20
var zPosition: CGFloat = 4
for _ in 1 ... 3 {
let newCalendarPage = UIView()
newCalendarPage.frame = CGRect(x: self.calendarView!.frame.origin.x + newCalendarPageSizeDifference / 2, y: self.calendarView!.frame.origin.y, width: self.calendarView!.frame.width - newCalendarPageSizeDifference, height: self.calendarView!.frame.height - newCalendarPageSizeDifference)
newCalendarPage.backgroundColor = .white
newCalendarPage.layer.zPosition = zPosition
newCalendarPage.layer.cornerRadius = self.setting.itemCardCornerRadius
newCalendarPage.setViewShadow()
self.view.addSubview(newCalendarPage)
UIView.animate(withDuration: 0.3, delay: 0, options: .curveEaseOut, animations: {
newCalendarPage.frame.origin.y -= newCalendarPageCordiateYDifference
})
zPosition -= 1
newCalendarPageCordiateYDifference += 10
newCalendarPageSizeDifference += 50
}
}
}
}

Answer 1

Remove self.view.addSubview(newCalendarPage) this from for loop and
Add subview like this
self.view.insertSubview(newCalendarPage, belowSubview: calendarView)
Another way is to disable user interaction like
newCalendarPage.isUserInteractionEnabled = false