如何在UISearchController中自定义searchBar？

Question

我知道如何为独立的UISearchBar设置外观，如下所示。

    let searchField = searchBar.value(forKey: "searchField") as? UITextField

    if let field = searchField {
        field.backgroundColor = UIColor.defaultBackgroundColor
        field.layer.cornerRadius = 15.0
        field.textColor = .white
        field.tintColor = .white

        field.font = UIFont.systemFont(ofSize: fl(13))
        field.layer.masksToBounds = true
        field.returnKeyType = .search
    }

但这不适用于UISearchController 。

我想将占位符的文本颜色和左放大镜图标设置为纯白色。 （现在看来它们上面有彩色层）。

另外，输入文字现在是黑色的，我也希望它是白色的。

总之，我想修改以下属性。
1. textField背景颜色
2. textFiled占位符文本颜色
3. textFiled文字颜色
4. textFiled字体

谁知道怎么做？

在viewDidAppear中添加以下代码：

            let placeholderString = NSAttributedString(string: "Placeholder", attributes: [NSAttributedStringKey.foregroundColor: UIColor.white])
            field.attributedPlaceholder = placeholderString

            let iconView = field.leftView as! UIImageView
            iconView.image = iconView.image?.withRenderingMode(.alwaysTemplate)
            iconView.tintColor = .white

Updata公司：
把这些设置放在ViewDidAppear()确实解决了我的一部分问题。
但是当我设置条形图的背景颜色时， textfield's background color发生了变化。
因为searchBar.barTintColor = .red .red在导航项中嵌入的iOS11的UISearchController中不起作用，所以我使用了searchBar.backgroundColor = .red
这让我很困惑。
那么如何分别改变searchBar的背景和textField的背景呢？

Answer 1

为搜索栏的文本字段设置attributedPlaceholder

@IBOutlet weak var sbSearchBar: UISearchBar!
if let textfield = sbSearchBar.value(forKey: "searchField") as? UITextField {

    textfield.backgroundColor = UIColor.red
    textfield.attributedPlaceholder = NSAttributedString(string: textfield.placeholder ?? "", attributes: [NSAttributedStringKey.foregroundColor : UIColor.white])

    if let leftView = textfield.leftView as? UIImageView {
        leftView.image = leftView.image?.withRenderingMode(.alwaysTemplate)
        leftView.tintColor = UIColor.white
    }

}

结果如下：

更新：

我想，这可能会对你有所帮助： 如何在searchcontroller中更改uitextfield颜色？

只需在此代码中应用颜色组合即可。

if #available(iOS 11.0, *) {
            let sc = UISearchController(searchResultsController: nil)
            sc.delegate = self
            let scb = sc.searchBar
            scb.tintColor = UIColor.white
            scb.barTintColor = UIColor.white


            if let textfield = scb.value(forKey: "searchField") as? UITextField {
                //textfield.textColor = // Set text color
                if let backgroundview = textfield.subviews.first {

                    // Background color
                    backgroundview.backgroundColor = UIColor.white

                    // Rounded corner
                    backgroundview.layer.cornerRadius = 10;
                    backgroundview.clipsToBounds = true;

                }
            }

            if let navigationbar = self.navigationController?.navigationBar {
                navigationbar.barTintColor = UIColor.blue
            }
            navigationItem.searchController = sc
            navigationItem.hidesSearchBarWhenScrolling = false

}

结果：

Answer 2

在viewDidAppear中添加以下代码：

            let placeholderString = NSAttributedString(string: "Placeholder", attributes: [NSAttributedStringKey.foregroundColor: UIColor.white])
            field.attributedPlaceholder = placeholderString

            let iconView = field.leftView as! UIImageView
            iconView.image = iconView.image?.withRenderingMode(.alwaysTemplate)
            iconView.tintColor = .white

更新 - 以下是自定义UISearchController颜色的完整代码：

override func viewDidAppear(_ animated: Bool) {

    //sets navigationbar backgroundColor
    if let navigationbar = self.navigationController?.navigationBar {
        navigationbar.barTintColor = UIColor.magenta
    }

    let searchField = searchController.searchBar.value(forKey: "searchField") as? UITextField

    //sets searchBar backgroundColor
    searchController.searchBar.backgroundColor = .blue

    if let field = searchField {
        field.layer.cornerRadius = 15.0
        //sets text Color
        field.textColor = .brown

        //sets indicator and cancel button Color
        field.tintColor = .green

        field.font = UIFont.systemFont(ofSize: 13)
        field.layer.masksToBounds = true
        field.returnKeyType = .search

        //sets placeholder text Color
        let placeholderString = NSAttributedString(string: "placeholder", attributes: [NSAttributedStringKey.foregroundColor: UIColor.red])
        field.attributedPlaceholder = placeholderString

        //sets icon Color
        let iconView = field.leftView as! UIImageView
        iconView.image = iconView.image?.withRenderingMode(.alwaysTemplate)
        iconView.tintColor = .cyan

        //sets textField backgroundColor
        if let backgroundview = field.subviews.first {
            backgroundview.backgroundColor = UIColor.yellow
        }
    }
}