在 swift 中居中圖像並添加背景

Question

所以我有一個屏幕，當應用程序在最近屏幕上時呈現。 但問題是，它位於左上角，我無法將其與中心對齊，也無法將背景設置為白色。 白色背景必須覆蓋屏幕，此圖像應位於中間。 到目前為止，我已經設法添加了圖像。 但在那之后沒有運氣。 任何幫助，將不勝感激。

  override func applicationWillResignActive(_ application: UIApplication) {
   if let view = self.window.rootViewController?.view.subviews.first(where: {$0.tag == TAG_BLUR_VIEW}){
       view.removeFromSuperview()
       blurView = nil
   }
    if blurView == nil{
        blurView = UIImageView(image: UIImage(named: "splash.jpg"))
        blurView?.backgroundColor = UIColor .white
        blurView?.tag = TAG_BLUR_VIEW
    }
    
    self.window.rootViewController?.view.insertSubview(blurView!, at: 0)

  }

Answer 1

最簡單的解決方案是使用中心 position。

if blurView == nil {
   let centerPos = self.window?.rootViewController?.view.center ?? .zero
   blurView?.center = centerPos
   self.window?.rootViewController?.view.addSubview(blurView!)
}

So the final code snippet based on the provided code is like the following.
override func applicationWillResignActive(_ application: UIApplication) {
   if let view = self.window.rootViewController?.view.subviews.first(where: {$0.tag == TAG_BLUR_VIEW}){
       view.removeFromSuperview()
       blurView = nil
   }
    if blurView == nil{
        blurView = UIImageView(image: UIImage(named: "splash.jpg"))
        blurView?.backgroundColor = UIColor .white
        blurView?.tag = TAG_BLUR_VIEW

        let centerPos = self.window?.rootViewController?.view.center ?? .zero
        blurView?.center = centerPos
    }
    
    self.window.rootViewController?.view.insertSubview(blurView!, at: 0)

  }

Answer 2

您需要為您的視圖指定約束。

override func viewDidLoad() {
        blurView.translatesAutoresizingMaskIntoConstraints = false
        blurView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
        // Add the other constraints such as topAnchor, leadingAnchor and trailingAnchor etc...
    }