问UIButton中图像下的标签

EN

/// This will move the TitleLabel text of a UIButton to below it's Image and Centered.
/// Note: No point in calling this function before autolayout lays things out.
/// - Parameter padding: Some extra padding to be applied
func centerVertically(padding: CGFloat = 18.0) {
    // No point in doing anything if we don't have an imageView size
    guard let imageFrame = imageView?.frame else { return }
    titleLabel?.numberOfLines = 0
    titleEdgeInsets.left = -(imageFrame.width + padding)
    titleEdgeInsets.top = (imageFrame.height + padding)
}

import UIKit

class CenteredButton: UIButton
{
    override func titleRect(forContentRect contentRect: CGRect) -> CGRect {
        let rect = super.titleRect(forContentRect: contentRect)

        return CGRect(x: 0, y: contentRect.height - rect.height + 5,
            width: contentRect.width, height: rect.height)
    }

    override func imageRect(forContentRect contentRect: CGRect) -> CGRect {
        let rect = super.imageRect(forContentRect: contentRect)
        let titleRect = self.titleRect(forContentRect: contentRect)

        return CGRect(x: contentRect.width/2.0 - rect.width/2.0,
            y: (contentRect.height - titleRect.height)/2.0 - rect.height/2.0,
            width: rect.width, height: rect.height)
    }

    override var intrinsicContentSize: CGSize {
        let size = super.intrinsicContentSize

        if let image = imageView?.image {
            var labelHeight: CGFloat = 0.0

            if let size = titleLabel?.sizeThatFits(CGSize(width: self.contentRect(forBounds: self.bounds).width, height: CGFloat.greatestFiniteMagnitude)) {
                labelHeight = size.height
            }

            return CGSize(width: size.width, height: image.size.height + labelHeight + 5)
        }

        return size
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        centerTitleLabel()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        centerTitleLabel()
    }

    private func centerTitleLabel() {
        self.titleLabel?.textAlignment = .center
    }
}

extension UIButton {

    func alignImageAndTitleVertically(padding: CGFloat = 6.0) {
        let imageSize = self.imageView!.frame.size
        let titleSize = self.titleLabel!.frame.size
        let totalHeight = imageSize.height + titleSize.height + padding

        self.imageEdgeInsets = UIEdgeInsets(
            top: -(totalHeight - imageSize.height),
            left: 0,
            bottom: 0,
            right: -titleSize.width
        )

        self.titleEdgeInsets = UIEdgeInsets(
            top: 0,
            left: -imageSize.width,
            bottom: -(totalHeight - titleSize.height),
            right: 0
        )
    }

}