Question

extension UISearchBar {

private func getViewElement<T>(type: T.Type) -> T? {

    let svs = subviews.flatMap { $0.subviews }
    guard let element = (svs.filter { $0 is T }).first as? T else { return nil }
    return element
}

func getSearchBarTextField() -> UITextField? {

    return getViewElement(type: UITextField.self)
}

func setTextColor(color: UIColor) {

    if let textField = getSearchBarTextField() {
        textField.textColor = color
    }
}

func setTextFieldColor(color: UIColor) {

    if let textField = getViewElement(type: UITextField.self) {
        switch searchBarStyle {
        case .minimal:
            textField.layer.backgroundColor = color.cgColor
            textField.layer.cornerRadius = 6

        case .prominent, .default:
            textField.backgroundColor = color
        }
    }
}

func setPlaceholderTextColor(color: UIColor) {

    if let textField = getSearchBarTextField() {
        textField.attributedPlaceholder = NSAttributedString(string: self.placeholder != nil ? self.placeholder! : "", attributes: [NSAttributedString.Key.foregroundColor:color])
    }
}

func setPlaceholderfont(fontfamily: UIFont) {

    if let textField = getSearchBarTextField() {
        textField.attributedPlaceholder = NSAttributedString(string: self.placeholder != nil ? self.placeholder! : "", attributes: [NSAttributedString.Key.font:fontfamily])
    }
}


 }

我为Uisearchbbar创建了一个扩展名，以便能够自定义占位符

在扩展名 setPlaceholderfont（）中运行正常

当我调用以下方法时，占位符文本的颜色不变

pick.searchBar.setPlaceholderTextColor(color: Server().primarycolor)

Answer 1

调用两种方法更新属性占位符的颜色和字体时，您将用最后一种覆盖。因此，假设您先设置颜色，然后再设置字体，则在设置字体属性时会删除color属性。

避免这种情况的一种简单方法是从一个单一的入口点开始，该入口点将更新占位符属性，颜色和字体设置方法都使用该占位符。我使用了同时具有getter和setter的计算属性-它可以获取和设置占位符的当前属性。

extension UITextField {
    var placeholderColor: UIColor? {
        get { return placeholderAttributes?[.foregroundColor] as? UIColor }
        set { placeholderAttributes?[.foregroundColor] = newValue }
    }

    var placeholderFont: UIFont? {
        get { return placeholderAttributes?[.font] as? UIFont }
        set { placeholderAttributes?[.font] = newValue }
    }

    var placeholderAttributes: [NSAttributedString.Key: Any]? {
        get { return attributedPlaceholder?.attributes(at: 0, effectiveRange: nil) }
        set { attributedPlaceholder = .init(string: placeholder ?? "", attributes: newValue) }
    }
}

因此，切回您的UISearchBar扩展名（我将getSearchBarTextField方法替换为计算属性textField），我们可以删除对属性字符串等的任何引用。

var textField: UITextField? {
    return getViewElement(type: UITextField.self)
}

func setTextColor(color: UIColor) {
    textField?.textColor = color
}

func setPlaceholderTextColor(color: UIColor) {
    textField?.placeholderColor = color
}

func setPlaceholderFont(font: UIFont) {
    textField?.placeholderFont = font
}

尽管在某些情况下，具有适当类型（UIColor，UIFont）的属性可能会派上用场，但从技术上讲，您不需要placeholderColor和placeholderFont属性，因为您可以使用扩展名中的文本字段placeholderAttributes设置它们。

extension UITextField {
    var placeholderAttributes: [NSAttributedString.Key: Any]? {
        get { return attributedPlaceholder?.attributes(at: 0, effectiveRange: nil) }
        set { attributedPlaceholder = .init(string: placeholder ?? "", attributes: newValue) }
    }
}

extension UISearchBar {

    // ...

    func setPlaceholderTextColor(color: UIColor) {
        textField?.placeholderAttributes?[.foregroundColor] = color
    }

    func setPlaceholderfont(fontfamily: UIFont) {
        textField?.placeholderAttributes?[.font] = fontfamily
    }
}

如何在搜索栏上设置更改占位符的颜色？

1 个答案: