我试图在swift中使用textKit对UITextView中的选定文本应用粗体和斜体。
这是代码:
let isBold = false
if !isActive(modification: .swapBoldWithItalic) || isBold{
storage.setAttributes(attributes, range: range)
} else {
let currentFont = attributes![.font] as? UIFont
let fontDescriptor = currentFont?.fontDescriptor
var changedFontDescriptor: UIFontDescriptor?
if fontDescriptor!.symbolicTraits.contains(.traitItalic) {
changedFontDescriptor = fontDescriptor?.withSymbolicTraits(fontDescriptor!.symbolicTraits.union(.traitItalic))
} else {
changedFontDescriptor = fontDescriptor?.withSymbolicTraits(fontDescriptor!.symbolicTraits.union(.traitBold))
}
var updatedFont: UIFont? = nil
if let changedFontDescriptor = changedFontDescriptor {
updatedFont = UIFont(descriptor: changedFontDescriptor, size: (currentFont?.pointSize)!)
}
let dict = [
NSAttributedString.Key.font: updatedFont,
NSAttributedString.Key.foregroundColor: UIColor.red
]
storage.setAttributes(dict, range: range)
}
我想要达到的是
- 将所选文本更改为粗体或斜体
- 将选中的文本从粗体改为斜体,反之亦然
现在的情况是,当我选择文本并将其更改为粗体时,它会更改为粗体,但当我尝试将另一个文本更改为斜体时,它也会更改为粗体,我仍然无法从粗体切换为斜体。
我猜你想通过不同的按钮切换粗体和斜体。我已经做了一个扩展,这将是很容易为您使用:
extension UIFont {
func byTogglingSymbolicTraits(_ symbolicTraits: UIFontDescriptor.SymbolicTraits) -> UIFont {
UIFont(
descriptor: fontDescriptor.byTogglingSymbolicTraits(symbolicTraits),
size: pointSize
)
}
}
extension UIFontDescriptor {
func byTogglingSymbolicTraits(_ traints: UIFontDescriptor.SymbolicTraits) -> UIFontDescriptor {
if symbolicTraits.contains(traints) {
return withSymbolicTraits(symbolicTraits.subtracting(traints))!
} else {
return withSymbolicTraits(symbolicTraits.union(traints))!
}
}
}
用法:
font = font.byTogglingSymbolicTraits(.traitBold)
// or
font = font.byTogglingSymbolicTraits(.traitItalic)