Question

我的问题在标题中已经有很多说明。我试图将动态类型（定义为here）添加到UISearchBar中，但没有运气。我知道这是可能的，因为系统应用程序似乎能够很好地处理它，如下所示：

但是，我的应用程序的显示效果似乎不如此处所示：

知道UITextField中包含UISearchBar，我自然尝试了此解决方案，但没有成功： UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).adjustsFontForContentSizeCategory = true

我也尝试过在线搜索/检查文档，但似乎找不到任何解决方案。要在UISearchBar中使用动态类型，我缺少什么了。

更新： @matt建议我手动检查并以这种方式更新字体。但是，这又产生了另一个问题，因为搜索栏本身太小，无法容纳如下所示的文本：

@matt建议也使用scaledValue(for:)方法来更新高度，但是这似乎不起作用。这是我正在使用的代码：

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
        super.traitCollectionDidChange(previousTraitCollection)
        UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).font = UIFont.preferredFont(forTextStyle: .body)
        let textFieldFrame = UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).frame
        UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).frame = CGRect(x: textFieldFrame.minX, y: textFieldFrame.minY, width: textFieldFrame.width, height: UIFontMetrics.default.scaledValue(for: textFieldFrame.height))
}

字体现在似乎正在使用此更新的代码进行缩放，但是搜索栏的高度并未增加：

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
    super.traitCollectionDidChange(previousTraitCollection)
    searchBar.textField?.font = UIFont.preferredFont(forTextStyle: .body)
    if let textFieldFrame = searchBar.textField?.frame {
        searchBar.textField?.frame = CGRect(x: textFieldFrame.minX, y: textFieldFrame.minY, width: textFieldFrame.width, height: UIFontMetrics.default.scaledValue(for: textFieldFrame.height))
    }
}

此外，这是我找到textField的方式（以防其他陷入困境的用户想知道）：

extension UISearchBar {
    var textField: UITextField? {
        var _textField: UITextField? = nil
        subviews.forEach {
            $0.subviews.forEach {
                if let textField = $0 as? UITextField {
                    _textField = textField
                }
            }
        }
        return _textField
    }
}

Answer 1

我遵循了这些里程碑，以实现您的目标：

使用动态类型功能（步骤1）自动调整字体。

适应搜索栏约束（STEP 2） 并其文本字段约束（STEP 3），当新{{3} }。

class SearchBarDynamicTypeVC: UIViewController {

@IBOutlet weak var mySearchBar: UISearchBar!

let fontHead = UIFont(name: "Chalkduster", size: 20.0)
let fontHeadMetrics = UIFontMetrics(forTextStyle: .title1)
var initialFrameHeight: CGFloat = 0.0


override func viewDidLoad() {
    super.viewDidLoad()

    UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).font = fontHeadMetrics.scaledFont(for: fontHead!)

    mySearchBar.textField?.adjustsFontForContentSizeCategory = true //STEP 1
}


override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    initialFrameHeight = mySearchBar.intrinsicContentSize.height

    if let textField = mySearchBar.textField {
        adaptConstraints(textField) //Initialization according to the first preferred content size category
    }
}


override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
    super.traitCollectionDidChange(previousTraitCollection)

    if let textField = mySearchBar.textField,
        let _ = previousTraitCollection {

        adaptConstraints(textField) // STEP 2 & 3
    }
}


private func adaptConstraints(_ textField: UITextField) {

//  Adapt the SEARCHBAR constraints
    mySearchBar.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.deactivate(mySearchBar.constraints)

    let heightSB = mySearchBar.heightAnchor.constraint(equalToConstant: fontHeadMetrics.scaledValue(for: initialFrameHeight))
    let widthSB = mySearchBar.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width - 20)
    let centerVSB = mySearchBar.centerYAnchor.constraint(equalTo: self.view.centerYAnchor)
    let centerHSB = mySearchBar.centerXAnchor.constraint(equalTo: self.view.centerXAnchor)

    NSLayoutConstraint.activate([centerVSB,
                                 centerHSB,
                                 widthSB,
                                 heightSB])

//  Adapt the SEARCHBAR TEXTFIELD constraints
    textField.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.deactivate(textField.constraints)

    let centerXTF = textField.centerXAnchor.constraint(equalTo: textField.superview!.centerXAnchor)
    let centerYTF = textField.centerYAnchor.constraint(equalTo: textField.superview!.centerYAnchor)
    let widthTF = textField.widthAnchor.constraint(equalTo: textField.superview!.widthAnchor, constant: -20.0)
    let heightTF = textField.heightAnchor.constraint(equalTo: textField.superview!.heightAnchor, constant: -20.0)

    NSLayoutConstraint.activate([centerXTF,
                                 centerYTF,
                                 widthTF,
                                 heightTF])
}
}

我使用了帖子中提供的代码段来获取搜索栏文本字段：

extension UISearchBar {

    var textField: UITextField? {

        var _textField: UITextField? = nil

        subviews.forEach {
            $0.subviews.forEach {
                if let textField = $0 as? UITextField {
                    _textField = textField
                }
            }
        }
        return _textField
    }
}

但是，您也可以使用键searchField来获取它，如下所示：

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

下面的快照显示了最终结果：

preferred content size category

您现在可以通过调整上面的代码段并自定义视觉上的个人选择（文本样式，字体，边距...），将动态类型添加到UISearchBar 。

将动态类型添加到UISearchBar

1 个答案: