Ios UIButton：如何使用 imageEdgeInsets 和 titleEdgeInsets 使图像和文本居中

无论如何，这里有一个通用的解决方案，可以在不使用任何幻数的情况下将图像定位在文本上方.Note that the following code is outdated and you should probably use one of the updated versions below:

// the space between the image and text
CGFloat spacing = 6.0;

// lower the text and push it left so it appears centered 
//  below the image
CGSize imageSize = button.imageView.frame.size;
button.titleEdgeInsets = UIEdgeInsetsMake(
  0.0, - imageSize.width, - (imageSize.height + spacing), 0.0);

// raise the image and push it right so it appears centered
//  above the text
CGSize titleSize = button.titleLabel.frame.size;
button.imageEdgeInsets = UIEdgeInsetsMake(
  - (titleSize.height + spacing), 0.0, 0.0, - titleSize.width);

以下版本包含以下 comments 中建议的支持iOS 7+的更改.我自己还没有测试过这段代码，所以我不确定它工作得有多好，或者如果在以前版本的iOS下使用，它是否会崩溃.

// the space between the image and text
CGFloat spacing = 6.0;

// lower the text and push it left so it appears centered 
//  below the image
CGSize imageSize = button.imageView.image.size;
button.titleEdgeInsets = UIEdgeInsetsMake(
  0.0, - imageSize.width, - (imageSize.height + spacing), 0.0);

// raise the image and push it right so it appears centered
//  above the text
CGSize titleSize = [button.titleLabel.text sizeWithAttributes:@{NSFontAttributeName: button.titleLabel.font}];
button.imageEdgeInsets = UIEdgeInsetsMake(
  - (titleSize.height + spacing), 0.0, 0.0, - titleSize.width);

// increase the content height to avoid clipping
CGFloat edgeOffset = fabsf(titleSize.height - imageSize.height) / 2.0;
button.contentEdgeInsets = UIEdgeInsetsMake(edgeOffset, 0.0, edgeOffset, 0.0);

Swift 5.0版

extension UIButton {
  func alignVertical(spacing: CGFloat = 6.0) {
    guard let imageSize = imageView?.image?.size,
      let text = titleLabel?.text,
      let font = titleLabel?.font
    else { return }

    titleEdgeInsets = UIEdgeInsets(
      top: 0.0,
      left: -imageSize.width,
      bottom: -(imageSize.height + spacing),
      right: 0.0
    )

    let titleSize = text.size(withAttributes: [.font: font])
    imageEdgeInsets = UIEdgeInsets(
      top: -(titleSize.height + spacing),
      left: 0.0,
      bottom: 0.0,
      right: -titleSize.width
    )

    let edgeOffset = abs(titleSize.height - imageSize.height) / 2.0
    contentEdgeInsets = UIEdgeInsets(
      top: edgeOffset,
      left: 0.0,
      bottom: edgeOffset,
      right: 0.0
    )
  }
}