Subview on top of window view in Swift

问题:

I want to place a UIView over the entire screen (including the navigation bar). This view will be black with 0.3 opacity. I want to do this to darken out the screen content and push a view on top of this. I am using this code:

UIApplication.sharedApplication().keyWindow?.addSubview(darkView)

This covers the whole screen as expected. However I now want to place another view on top of this dark view. Is there a way to do this? Everything I try just results in the view being under the dark view. Any pointers would be really appreciated! thanks

回答1:

It's really simple.

You just add another view to window! And it will be there, on top of the first view you added. For example, this code adds a black view and a white view:

let window = UIApplication.sharedApplication().keyWindow!
let v = UIView(frame: window.bounds)
window.addSubview(v);
v.backgroundColor = UIColor.blackColor()
let v2 = UIView(frame: CGRect(x: 50, y: 50, width: 100, height: 50))
v2.backgroundColor = UIColor.whiteColor()
window.addSubview(v2)

You can also add the new view as a sub view of the first view you added:

let window = UIApplication.sharedApplication().keyWindow!
let v = UIView(frame: window.bounds)
window.addSubview(v);
v.backgroundColor = UIColor.blackColor()
let v2 = UIView(frame: CGRect(x: 50, y: 50, width: 100, height: 50))
v2.backgroundColor = UIColor.whiteColor()
v.addSubview(v2)

Swift 4

let window = UIApplication.shared.keyWindow!
    let v = UIView(frame: window.bounds)
    window.addSubview(v);
    v.backgroundColor = UIColor.black
    let v2 = UIView(frame: CGRect(x: 50, y: 50, width: 100, height: 50))
    v2.backgroundColor = UIColor.white
    v.addSubview(v2)

Simple!

回答2:

For SWIFT 3 use this:

let window = UIApplication.shared.keyWindow!
window.addSubview(someView)

回答3:

Swift 4, Adding a UIViewController as a subview to UIWindow

This code is for adding view controller as a subview, covering the whole window with simple animation.

let appDelegate = UIApplication.shared.delegate as! AppDelegate
var customReviewPopup = ReviewPopupViewController.init(nibName: "ReviewPopupViewController", bundle: Bundle.main)

self.appDelegate.window?.addSubview((customReviewPopup.view)!)
self.customReviewPopup.view.frame = (self.appDelegate.window?.bounds)!
self.customReviewPopup.view.alpha = 0
self.customReviewPopup.view.isHidden = true

UIView.animate(withDuration: 0.3, delay: 0, options: .transitionCrossDissolve, animations: {
    self.customReviewPopup.view.isHidden = false
    self.customReviewPopup.view.alpha = 1
}, completion: nil)