问使用UIView 4约束关闭容器DropDownMenu中的面板

EN

override func didMoveToSuperview() {
    self.superview?.addSubview(dropView)
    self.superview?.bringSubview(toFront: dropView)
    dropView.topAnchor.constraint(equalTo: self.bottomAnchor).isActive = true // Having issue here for bottom anchor when closing the UIViewController
    dropView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
    dropView.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
    height = dropView.heightAnchor.constraint(equalToConstant: 0)
}

isHidden = !isHidden
        animateStatusBar()
        hideGrayCoverView()

        animateCenterPanelYPosition(targetPosition: 0) { (finished) in
            if finished {
                self.currentState = .collapsed
                if let mapSettings = self.mapFilterSettingsVC {
                    mapSettings.view.removeFromSuperview()
                    mapSettings.removeFromParentViewController()
                }
                self.mapFilterSettingsVC = nil
            }
        }