ios - 约束不适用于 UINavigationBar 项目

Question

我正在尝试为 UISearchbar 提供前导和尾随空间。我几乎已经尝试了一切。高度、宽度、前导和尾随约束但没有任何作用。请让我知道如何在我以编程方式加载导航栏项目时应用约束。

func setupsearchbar() {
    //  Setup the Search Controller
    searchcontroller.searchResultsUpdater = self as? UISearchResultsUpdating
    searchcontroller.hidesNavigationBarDuringPresentation = false
    searchcontroller.searchBar.placeholder = "Search"
    self.navigationItem.titleView = searchcontroller.searchBar
    searchcontroller.searchBar.delegate = self
    searchcontroller.searchBar.translatesAutoresizingMaskIntoConstraints = false
    searchcontroller.searchBar.widthAnchor.constraint(lessThanOrEqualToConstant: 100.0).isActive = true


    if let textfield = searchcontroller.searchBar.value(forKey: "searchField") as? UITextField {

        textfield.textColor = UIColor.blue

        if let backgroundview = textfield.subviews.first {

            // Background color
            backgroundview.backgroundColor = UIColor.white

            backgroundview.layer.cornerRadius = 18
            backgroundview.clipsToBounds = true;
        }
    }

}

请帮助我解释为什么我的导航栏没有响应约束。

Answer 1

也许你会失去这个:self.view.clipsToBounds = true

backgroundview.layer.cornerRadius = 18
backgroundview.clipsToBounds = true;
self.view.clipsToBounds = true