iOS - How to use `NSMutableString` in swift

橙三吉。 提交于 2019-12-03 16:25:45

Here's a basic implementation. It seemed pretty straightforward to me, and you didn't provide your attempt, so I'm not sure if you have something similar and there's a problem with it, or if you're just new to Swift.

One difference is that this implementation uses optional casting (as?), which I did to demonstrate the concept. In practice, this doesn't need to be optional since NSFontAttributeName is guaranteed to provide a 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()

Hope it helps!

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;
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