将Subview置于一切之上，但置于另一个UIView之下

Question

I am trying to place a UIView - popupView at the top, and another UIView (opaqueView) below popupView but above anything else. PopUpView is connected with an Outlet.

func display() {
    popupView.center = CGPointMake(CGRectGetMidX(self.view.bounds), tableView.center.y);
    self.view.addSubview(popupView)
    popupView.clipsToBounds = true

    let opaqueView = UIView()
    let screenSize: CGRect = UIScreen.mainScreen().bounds
    opaqueView.frame.size = CGSize(width: screenSize.width, height: screenSize.height)
    opaqueView.alpha = 0.6
    UIApplication.sharedApplication().keyWindow!.insertSubview(opaqueView, belowSubview: popupView) 
}

Using this approach causes the opaqueView getting placed over everything including the popupView. Instead, I want to have popupView above opaqueView but keep opaqueView above everything else (view, TabBar, NavBar)

Answer 1

parent.insertSubview(child, belowSubview: sibling) works only when the sibling is a direct child of parent , so that child and sibling share the same parent. The current code does not work because opaqueView (the child) and popupView (the sbiling) have different parents.

That means either ① popupView should use the keyWindow as the parent, or ② opaqueView should use self.view as parent. Since you want opaqueView be above of everything, option ① is the only solution.