iOS - 如何在swift中使用`NSMutableString`

Question

我已经看过这个Objective-C代码,但我很难在swift中做同样的事情:

NSMutableAttributedString *res = [self.richTextEditor.attributedText mutableCopy];

[res beginEditing];
__block BOOL found = NO;
[res enumerateAttribute:NSFontAttributeName inRange:NSMakeRange(0, res.length) options:0 usingBlock:^(id value, NSRange range, BOOL *stop) {
    if (value) {
        UIFont *oldFont = (UIFont *)value;
        UIFont *newFont = [oldFont fontWithSize:oldFont.pointSize * 2];
        [res removeAttribute:NSFontAttributeName range:range];
        [res addAttribute:NSFontAttributeName value:newFont range:range];
        found = YES;
    }
}];
if (!found) {
    // No font was found - do something else?
}
[res endEditing];
self.richTextEditor.attributedText = res;

我试图NSMutableAttributedString通过迭代每个属性来改变a中的字体.我很高兴听到有更好的方法,但如果有人能帮助我翻译上述内容,我会感到非常满意.

Answer 1

这是一个基本的实现.这对我来说似乎很简单,你没有提供你的尝试,所以我不确定你是否有类似的东西,它有问题,或者如果你刚刚接触Swift.

一个区别是这个实现使用了可选的cast(as?),我用它来演示这个概念.在实践中,这不需要是可选的,因为NSFontAttributeName保证提供UIFont.

var res : NSMutableAttributedString = NSMutableAttributedString(string: "test");

res.beginEditing()

var found = false

res.enumerateAttribute(NSFontAttributeName, inRange: NSMakeRange(0, res.length), options: NSAttributedStringEnumerationOptions(0)) { (value, range, stop) -> Void in
    if let oldFont = value as? UIFont {
        let newFont = oldFont.fontWithSize(oldFont.pointSize * 2)
        res.removeAttribute(NSFontAttributeName, range: range)
        res.addAttribute(NSFontAttributeName, value: newFont, range: range)
        found = true
    }
}

if found == false {

}

res.endEditing()

Answer 2

希望能帮助到你!

var res : NSMutableAttributedString = self.richTextEditor.attributedText!
res.beginEditing()    
var found : bool = false;    
res.enumerateAttribute(NSFontAttributeName,inRange:NSMakeRange(0, res.length),options:0, usingBlock(value:AnyObject!, range:NSRange, stop:UnsafeMutablePointer<ObjCBool>) -> Void in {
    if (value) {
        let oldFont = value as UIFont;
        let newFont = oldFont.fontWithSize(oldFont.pointSize * 2)
        res.removeAttribute(NSFontAttributeName , range:range)
        res.addAttribute(NSFontAttributeName value:newFont range:range)
        found = true
    }
})
if !found {
    // No font was found - do something else?
}
res.endEditing()
self.richTextEditor.attributedText = res;