这是我之前发现的问题 here 的跟进

我正在使用 MarkdownTextView将基本 Markdown 添加到 UITextView。 TextView 是 MarkdownTextView 的子类。

在我之前的问题中使用复制和粘贴时出现以下错误

Fatal error: Use of unimplemented initializer 'init()' for class MarkdownTextStorage

直到我将以下初始化程序添加到 MarkdownTextStorage 类

public override convenience init() {
    self.init(attributes: MarkdownAttributes())
}

public init(attributes: MarkdownAttributes = MarkdownAttributes()) {
    self.attributes = attributes
    super.init()
    commonInit()

    if let headerAttributes = attributes.headerAttributes {
        addHighlighter(MarkdownHeaderHighlighter(attributes: headerAttributes))
    }
    addHighlighter(MarkdownLinkHighlighter())
    addHighlighter(MarkdownListHighlighter(markerPattern: "[*+-]", attributes: attributes.unorderedListAttributes, itemAttributes: attributes.unorderedListItemAttributes))
    addHighlighter(MarkdownListHighlighter(markerPattern: "\\d+[.]", attributes: attributes.orderedListAttributes, itemAttributes: attributes.orderedListItemAttributes))

    // From markdown.pl v1.0.1 <http://daringfireball.net/projects/markdown/>

    // Code blocks
    addPattern("(?:\n\n|\\A)((?:(?:[ ]{4}|\t).*\n+)+)((?=^[ ]{0,4}\\S)|\\Z)", attributes.codeBlockAttributes)

    // Block quotes
    addPattern("(?:^[ \t]*>[ \t]?.+\n(.+\n)*\n*)+", attributes.blockQuoteAttributes)

    // Se-text style headers
    // H1
    addPattern("^(?:.+)[ \t]*\n=+[ \t]*\n+", attributes.headerAttributes?.h1Attributes)

    // H2
    addPattern("^(?:.+)[ \t]*\n-+[ \t]*\n+", attributes.headerAttributes?.h2Attributes)

    // Emphasis
    addPattern("(\\*|_)(?=\\S)(.+?)(?<=\\S)\\1", attributesForTraits(.traitItalic, attributes.emphasisAttributes))

    // Strong
    addPattern("(\\*\\*|__)(?=\\S)(?:.+?[*_]*)(?<=\\S)\\1", attributesForTraits(.traitBold, attributes.strongAttributes))

    // Inline code
    addPattern("(`+)(?:.+?)(?<!`)\\1(?!`)", attributes.inlineCodeAttributes)
}

但是一旦我这样做了，每次复制和粘贴时我都会遇到以下错误。

似乎每次用户复制和粘贴时，初始化程序都会在更改为 ViewController 中设置的字体属性之前设置默认的 MarkdownAttributes。此屏幕截图位于正在设置的文本属性之间。

这就是我在 ViewController 中使用 TextStorage 来设置文本属性的方式

let fonty = UIFont(name: font, size: fsize)

attributes.defaultAttributes[NSFontAttributeName] = fonty
attributes.orderedListAttributes?[NSFontAttributeName] = fonty
attributes.orderedListItemAttributes?[NSFontAttributeName] = fonty
attributes.unorderedListAttributes?[NSFontAttributeName] = fonty
attributes.unorderedListItemAttributes?[NSFontAttributeName] = fonty

let textStorage = MarkdownTextStorage(attributes: attributes)

这是 MarkdownAttributes 结构

public struct MarkdownAttributes {

let fonty = UIFont(name: "OpenSans", size: 30)

public var defaultAttributes: TextAttributes = [
    NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.body)

]

public var strongAttributes: TextAttributes?
public var emphasisAttributes: TextAttributes?

public struct HeaderAttributes {
    public var h1Attributes: TextAttributes? = [
        NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.headline)
    ]

    public var h2Attributes: TextAttributes? = [
        NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.headline)
    ]

    public var h3Attributes: TextAttributes? = [
        NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.headline)
    ]

    public var h4Attributes: TextAttributes? = [
        NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.subheadline)
    ]

    public var h5Attributes: TextAttributes? = [
        NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.subheadline)
    ]

    public var h6Attributes: TextAttributes? = [
        NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.subheadline)
    ]

    func attributesForHeaderLevel(_ level: Int) -> TextAttributes? {
        switch level {
        case 1: return h1Attributes
        case 2: return h2Attributes
        case 3: return h3Attributes
        case 4: return h4Attributes
        case 5: return h5Attributes
        case 6: return h6Attributes
        default: return nil
        }
    }

    public init() {}
}

public var headerAttributes: HeaderAttributes? = HeaderAttributes()

fileprivate static let MonospaceFont: UIFont = {
    let bodyFont = UIFont.preferredFont(forTextStyle: UIFontTextStyle.body)
    let size = bodyFont.pointSize
    return UIFont(name: "Menlo", size: size) ?? UIFont(name: "Courier", size: size) ?? bodyFont
}()

public var codeBlockAttributes: TextAttributes? = [
    NSFontAttributeName: MarkdownAttributes.MonospaceFont
]

public var inlineCodeAttributes: TextAttributes? = [
    NSFontAttributeName: MarkdownAttributes.MonospaceFont
]

public var blockQuoteAttributes: TextAttributes? = [
    NSForegroundColorAttributeName: UIColor.darkGray
]

public var orderedListAttributes: TextAttributes? = [
    NSFontAttributeName: fontWithTraits(.traitBold, font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.body))
]

public var orderedListItemAttributes: TextAttributes? = [
    NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.body),
    NSForegroundColorAttributeName: UIColor.darkGray
]

public var unorderedListAttributes: TextAttributes? = [
    NSFontAttributeName: fontWithTraits(.traitBold, font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.body))
]

public var unorderedListItemAttributes: TextAttributes? = [
    NSFontAttributeName: UIFont.preferredFont(forTextStyle: UIFontTextStyle.body),
    NSForegroundColorAttributeName: UIColor.darkGray
]

public init() {

}

有谁知道我该如何修复该错误，以便在调用初始化程序时将值设置为用户定义的值而不是默认值？

最佳答案

添加一个接受用户定义值的 init 函数，并调用您的类或您的父类(super class) init()(取决于您想要做什么..)

您应该只添加以下功能之一，您不想同时添加它们:

public override init(attributes: MarkdownAttributes = MarkdownAttributes()) {
   super.init(attributes)
}

public override convenience init(attributes: MarkdownAttributes = MarkdownAttributes()) {
     init(attributes: attributes)
}

要调用它，您现在可以使用上面显示的代码:

let fonty = UIFont(name: font, size: fsize)

attributes.defaultAttributes[NSFontAttributeName] = fonty
attributes.orderedListAttributes?[NSFontAttributeName] = fonty
attributes.orderedListItemAttributes?[NSFontAttributeName] = fonty
attributes.unorderedListAttributes?[NSFontAttributeName] = fonty
attributes.unorderedListItemAttributes?[NSFontAttributeName] = fonty

let textStorage = MarkdownTextStorage(attributes: attributes)

关于ios - 调用初始化程序时更改属性值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54102138/