变化斯威夫特

Question

AttributedText的只是字体我有一些在IB创建UILabels这一切都已归于文本。每个标签的文本都包含多行不同字体大小和颜色。

在运行时，我希望能够在不更改现有字体大小或颜色的情况下更改这些标签的字体名称。

我已经研究过，无法找到一个简单的方法来实现这一点。有任何想法吗？

Answer 1

你首先需要了解苹果公司用来描述字体的行话

• Helvetica是家庭
• Helvetica Bold，Helvetica Italic，Helvetica Bold Italic，Helvetica Display等都是面临
• Helvetica Bold, 12pt是一个字体

你需要的是更换一个属性串的字体家族：

let newAttributedString = NSMutableAttributedString(attributedString: label.attributedText) 

// Enumerate through all the font ranges 
newAttributedString.enumerateAttribute(NSFontAttributeName, in: NSMakeRange(0, newAttributedString.length), options: []) { value, range, stop in 
    guard let currentFont = value as? UIFont else { 
     return 
    } 

    // An NSFontDescriptor describes the attributes of a font: family name, face name, point size, etc. 
    // Here we describe the replacement font as coming from the "Hoefler Text" family 
    let fontDescriptor = currentFont.fontDescriptor.addingAttributes([UIFontDescriptorFamilyAttribute: "Hoefler Text"]) 

    // Ask the OS for an actual font that most closely matches the description above 
    if let newFontDescriptor = fontDescriptor.matchingFontDescriptors(withMandatoryKeys: [UIFontDescriptorFamilyAttribute]).first { 
     let newFont = UIFont(descriptor: newFontDescriptor, size: currentFont.pointSize) 
     newAttributedString.addAttributes([NSFontAttributeName: newFont], range: range) 
    } 
} 

label.attributedText = newAttributedString 

原件（旧金山）：

更换（Hoefler文本）：

Answer 2

以上的伟大工程，但与Swift4和9.1的Xcode我得到这个方法的名字改变了警告的数量。以下是应用所有这些警告的结果。否则，我没有改变任何东西。

let newAttributedString = NSMutableAttributedString(attributedString: label.attributedText!) 

// Enumerate through all the font ranges 
newAttributedString.enumerateAttribute(NSAttributedStringKey.font, in: NSMakeRange(0, newAttributedString.length), options: []) 
{ 
    value, range, stop in 
    guard let currentFont = value as? UIFont else { 
     return 
    } 

    // An NSFontDescriptor describes the attributes of a font: family name, face name, point size, etc. 
    // Here we describe the replacement font as coming from the "Hoefler Text" family 
    let fontDescriptor = currentFont.fontDescriptor.addingAttributes([UIFontDescriptor.AttributeName.family: "Hoefler Text"]) 

    // Ask the OS for an actual font that most closely matches the description above 
    if let newFontDescriptor = fontDescriptor.matchingFontDescriptors(withMandatoryKeys: [UIFontDescriptor.AttributeName.family]).first { 
     let newFont = UIFont(descriptor: newFontDescriptor, size: currentFont.pointSize) 
     newAttributedString.addAttributes([NSAttributedStringKey.font: newFont], range: range) 
    } 
} 

label.attributedText = newAttributedString