Swift iOS : YYText计算文字占用高度

使用动态文字填充UITableViewCell内容时，需要计算文字占用高度，以便告知UITableViewCell的行高。使用YYText的YYTextLayout可以帮助做到这点。

如下案例，简单封装了YYTextLayout，并通过两个案例调用，演示它的做法：

import UIKit
import YYText
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        let a = "I'm trying to import myFramework into a project. I've added ... If I get you correctly you don't have a separate build target for your framework (you"
        print(Foo.OccupyHigh(a,UIScreen.main.bounds.size.width - 24))
        print(Foo.OccupyHigh(a+a,UIScreen.main.bounds.size.width - 24))
        return true
    }
}
class Foo {
    class func getYYLayout(_ title : String?)->YYTextLayout?{
        return getYYLayout(title,UIScreen.main.bounds.size.width - 24)
    }
    class func getYYLayout(_ title : String?, _ width : CGFloat)->YYTextLayout?{
        var topicTitleAttributedString: NSMutableAttributedString?
        var topicTitleLayout: YYTextLayout?
        let r :CGFloat = 15.0
        let g :CGFloat = 15.0
        let b :CGFloat = 15.0
        topicTitleAttributedString = NSMutableAttributedString(string: title!,
                                                               attributes: [
                                                                NSFontAttributeName:v2Font(17),
                                                                NSForegroundColorAttributeName:UIColor(red: r/255.0, green: g/255.0, blue: b/255.0, alpha: 255),
                                                                ])
        topicTitleAttributedString?.yy_lineSpacing = 3
        topicTitleLayout = YYTextLayout(containerSize: CGSize(width: width, height: 9999), text: topicTitleAttributedString!)
        return topicTitleLayout
    }
    class func OccupyHigh(_ title : String, _ width : CGFloat) -> CGFloat{
        let topicTitleLayout = getYYLayout(title,width)
        return topicTitleLayout?.textBoundingRect.size.height ?? 0
    }
}

核心为OccupyHigh函数，告诉它文字的内容和希望的宽度，就可以得到它的占用高度。