UILabel的单个字符的宽度？

Question

I want to find number of characters that can be displayed on single line of UILabel

I have width of single line

Answer 1

You can use

func getWidthFor(title: String) -> CGFloat {
    let font = UIFont(name: "YourFont", size: 13.0)
    let fontAttributes = [NSAttributedString.Key.font: font]
    let size = title.size(withAttributes: fontAttributes as [NSAttributedString.Key: Any])
    return size.width
}

And then either send on character as a string, or send whole text and check if it fits.

Answer 2

Try this Find the number of characters that fits in a UITextView with constant width and height with a given string?

func numberOfCharactersThatFitLabel() -> Int {

    // Create an 'CTFramesetterRef' from an attributed string
    let fontRef = CTFontCreateWithName(font.fontName as CFString?, font.pointSize, nil)
    var attributes: [AnyHashable : Any]? = nil
    if let fontRef = fontRef {
        attributes = [kCTFontAttributeName : fontRef]
    }
    let attributedString = NSAttributedString(string: text, attributes: attributes as? [NSAttributedString.Key : Any])
    let frameSetterRef = CTFramesetterCreateWithAttributedString(attributedString as CFAttributedString?)

    // Get a suggested character count that would fit the attributed string
    var characterFitRange: CFRange
    CTFramesetterSuggestFrameSizeWithConstraints(frameSetterRef, CFRangeMake(0, 0), nil, CGSize(width: bounds.size.width, height: CGFloat(numberOfLines) * font.lineHeight), &characterFitRange)
    return Int(characterFitRange.length)
} 

Answer 3

In objective-C you can estimate it not exactly, but there is a work around: Get specific letter in string and determine letter size. Using UILabel frame width you can calculate average number of characters which can be displayed in single line.

NSString *letter = [label.text substringWithRange:NSMakeRange(index, 1)];

CGSize letterSize = [letter sizeWithFont:self.font];

NSNumber* numberOfCharacters = UILabel.frame.Size.width / letterSize;

if it can help you. Also it will work accurate if you have used monospaced font.