ios - UINavigationController - 使用 UIBlurEffect 清除背景

Question

我在 UIViewController 中使用 UIBlurEffect，它以 .crossDissolve 过渡样式呈现。 UIViewController 在其 View 中添加了一个 collectionView，因此两者都有清晰的背景。

HomeViewController.swift

func showLiveDealsCategory(sender:UITextField){
    let catSelection = LiveDealCategorySelection()
    //let navContr = UINavigationController(rootViewController: catSelection)
    catSelection.modalPresentationStyle = .custom
    catSelection.modalTransitionStyle = .crossDissolve
    self.present(catSelection, animated: true, completion: nil)
}

LiveDealCategorySelection.swift

func setupBackgroundView(){
    if !UIAccessibilityIsReduceTransparencyEnabled() {
        self.view.backgroundColor = .clear
        let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.dark)
        let blurEffectView = UIVisualEffectView(effect: blurEffect)
        blurEffectView.frame = (self.view?.bounds)!
        blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        self.view?.addSubview(blurEffectView)
    } else {
        self.collectionView?.backgroundColor = UIColor.black
    }
}

这是您可以在 LiveDealCategorySelection 后面看到 mapView 的结果:

问题是当我将 View Controller 嵌入 UINavigationController 时，因为我无法将其背景颜色设置为 .clear:

func showLiveDealsCategory(sender:UITextField){
        let catSelection = LiveDealCategorySelection()
        let navContr = UINavigationController(rootViewController: catSelection)
        catSelection.modalPresentationStyle = .custom
        catSelection.modalTransitionStyle = .crossDissolve
        self.present(navContr, animated: true, completion: nil)
}

在 LiveDealCategorySelection 我试过:

 override func viewWillAppear(_ animated: Bool) {
        if self.navigationController != nil {
            self.navigationController!.view.backgroundColor = .clear
            self.navigationController!.view.tintColor = .clear
        }
  }

当我实例化导航 Controller 时，我还尝试将背景颜色设置为 .clear，但我得到的是黑色背景。有什么想法吗？

Answer 1

您只是忘记将演示样式移动到 UINavigationController

navContr.modalPresentationStyle = .custom