A UILabel subclass that detects and attempts to fix intrinsicContentSize bugs in UILabel on iOS 11

iOS11CompatibleLabel.swift

import UIKit

/// A UILabel subclass that detects and attempts to fix intrinsicContentSize bugs in UILabel
class iOS11CompatibleLabel: UILabel {

    override var intrinsicContentSize: CGSize {

        // First attempt at a fix...
        // All UILabels that misbehave have numberOfLines==0 and preferredMaxLayoutWidth=0
        //  but all UILabels that have these two properties as 0 do not necessarily misbehave
        // So this fix worked, but modified the label unecessarily some of the time
        // Note that on subsequent passes, UIKit sets preferredMaxLayoutWidth to a non-zero value, presumably to iterate onto the correct height for the label.
        //        let shouldAdjustNumberOfLines = self.label.numberOfLines == 0 && self.label.preferredMaxLayoutWidth == 0

        // Second attempt at a fix...
        // This is a little more hacky but doesn't have any false positives as the above attempt does
        guard super.intrinsicContentSize.width > 1000000000.0 else {

            return super.intrinsicContentSize
        }

        var count = 0

        if let text = self.text {

            text.enumerateLines {(_, _) in
                count += 1
            }

        } else {

            count = 1
        }

        let oldNumberOfLines = self.numberOfLines

        self.numberOfLines = count
        let size = super.intrinsicContentSize

        self.numberOfLines = oldNumberOfLines

        return size
    }
}