ios - 如何从按钮中的第一行和第二行标题中获取文本

Question

如何从按钮的第一行和第二行获取文本？以及如何获得按钮标题中使用了多少行？

我创建了一个按钮:

let button = UIButton(type: UIButtonType.Custom) as UIButton
button.frame = CGRectMake(15, 30, 150, 30)
button.setTitle(title, forState: .Normal)
button.titleLabel?.adjustsFontSizeToFitWidth = true
button.titleLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping;

然后我想获取按钮用于显示标题的行数。我想获取按钮标题第一行的文本。

Answer 1

通过一些计算，您可以获得UIButton 标题的行数并获得第一行字符串。我想创建一些扩展以使代码“最便携”

从您的代码开始:

let button = UIButton(type: UIButtonType.Custom) as UIButton
let title = "Lorem ipsum dolor sit amet, legimus tacimates eam in. Inani petentium iudicabit nam ut, verear nostrud in sea. Everti repudiare comprehensam et has"
button.frame = CGRectMake(15, 150, 150, 30)
button.setTitle(title, forState: .Normal)
button.titleLabel?.adjustsFontSizeToFitWidth = true
button.setTitleColor(UIColor.blackColor(), forState: UIControlState.Normal)
button.titleLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping
self.view.addSubview(button)

因此，首先添加这些扩展:

extension UIFont {
    func sizeOfString(string:String) -> CGSize {
        return (string as NSString).sizeWithAttributes([NSFontAttributeName:self])
    }
    func sizeOfStringConstrained(string: String, constrainedToWidth width: Double) -> CGSize {
        return NSString(string: string).boundingRectWithSize(CGSize(width: width, height: DBL_MAX),
                                                             options: NSStringDrawingOptions.UsesLineFragmentOrigin,
                                                             attributes: [NSFontAttributeName: self],
                                                             context: nil).size
    }
}

extension UIButton {
    func getLinesArrayOfString() -> [String] {

        let text:NSString = (self.titleLabel?.text)!
        let font:UIFont =  self.titleLabel!.font
        let rect:CGRect = self.frame

        let myFont:CTFontRef = CTFontCreateWithName(font.fontName, font.pointSize, nil)
        let attStr:NSMutableAttributedString = NSMutableAttributedString(string: text as String)
        attStr.addAttribute(String(kCTFontAttributeName), value:myFont, range: NSMakeRange(0, attStr.length))
        let frameSetter:CTFramesetterRef = CTFramesetterCreateWithAttributedString(attStr as CFAttributedStringRef)
        let path:CGMutablePathRef = CGPathCreateMutable()
        CGPathAddRect(path, nil, CGRectMake(0, 0, rect.size.width, 100000))
        let frame:CTFrameRef = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
        let lines = CTFrameGetLines(frame) as NSArray
        var linesArray = [String]()

        for line in lines {
            let lineRange = CTLineGetStringRange(line as! CTLine)
            let range:NSRange = NSMakeRange(lineRange.location, lineRange.length)
            let lineString = text.substringWithRange(range)
            linesArray.append(lineString as String)
        }
        return linesArray
    }
}

然后，编写此代码以获得结果:

let font = button.titleLabel?.font
let sizeString = font?.sizeOfString(title)
let sizeStringConstrained = font?.sizeOfStringConstrained(title, constrainedToWidth: Double(button.frame.width))
let division = (sizeStringConstrained?.height)!/(sizeString?.height)!
let numLines = Int(ceil(division))
print("Number of lines used in my button title: \(numLines)")

let array = button.getLinesArrayOfString()
print("The first line of my button title is: \(array.first)")