斯威夫特3:

open override func imageRect(forContentRect contentRect: CGRect) -> CGRect {
    var frame = super.imageRect(forContentRect: contentRect)
    let  imageWidth = frame.size.width
    var titleRect = CGRect.zero
    titleRect.size = self.title(for: self.state)!.size(attributes: [NSFontAttributeName: self.titleLabel!.font])
    titleRect.origin.x = (self.frame.size.width - (titleRect.size.width + imageWidth)) / 2.0 + self.titleEdgeInsets.left - self.titleEdgeInsets.right;
    frame.origin.x = titleRect.origin.x + titleRect.size.width - self.imageEdgeInsets.right + self.imageEdgeInsets.left;
    return frame
}

open override func titleRect(forContentRect contentRect: CGRect) -> CGRect {
    var frame = super.titleRect(forContentRect: contentRect)
    if let imageWidth = self.image(for: self.state)?.size.width {
        frame.origin.x = (self.frame.size.width - (frame.size.width + imageWidth)) / 2.0 + self.titleEdgeInsets.left - self.titleEdgeInsets.right;
    }
    return frame
}

我决定不使用标准的按钮图像视图，因为所提出的移动它的解决方案感觉很俗气。这让我获得了想要的美感，并且通过改变约束来重新定位按钮是很直观的:

extension UIButton {
    func addRightIcon(image: UIImage) {
        let imageView = UIImageView(image: image)
        imageView.translatesAutoresizingMaskIntoConstraints = false

        addSubview(imageView)

        let length = CGFloat(15)
        titleEdgeInsets.right += length

        NSLayoutConstraint.activate([
            imageView.leadingAnchor.constraint(equalTo: self.titleLabel!.trailingAnchor, constant: 10),
            imageView.centerYAnchor.constraint(equalTo: self.titleLabel!.centerYAnchor, constant: 0),
            imageView.widthAnchor.constraint(equalToConstant: length),
            imageView.heightAnchor.constraint(equalToConstant: length)
        ])
    }
}

子类化UIButton是完全没有必要的。相反，你可以简单地为图像设置一个高的左插入值，为标题设置一个小的右插入值。就像这样:

button.imageEdgeInsets = UIEdgeInsetsMake(0., button.frame.size.width - (image.size.width + 15.), 0., 0.);
button.titleEdgeInsets = UIEdgeInsetsMake(0., 0., 0., image.size.width);

更新:Swift 3

class ButtonIconRight: UIButton {
    override func imageRect(forContentRect contentRect:CGRect) -> CGRect {
        var imageFrame = super.imageRect(forContentRect: contentRect)
        imageFrame.origin.x = super.titleRect(forContentRect: contentRect).maxX - imageFrame.width
        return imageFrame
    }

    override func titleRect(forContentRect contentRect:CGRect) -> CGRect {
        var titleFrame = super.titleRect(forContentRect: contentRect)
        if (self.currentImage != nil) {
            titleFrame.origin.x = super.imageRect(forContentRect: contentRect).minX
        }
        return titleFrame
    }
}

Swift 2的原始答案:

一个解决方案，处理所有水平对齐，与一个Swift实现示例。如果需要，只需翻译成Objective-C即可。

class ButtonIconRight: UIButton {
    override func imageRectForContentRect(contentRect:CGRect) -> CGRect {
        var imageFrame = super.imageRectForContentRect(contentRect)
        imageFrame.origin.x = CGRectGetMaxX(super.titleRectForContentRect(contentRect)) - CGRectGetWidth(imageFrame)
        return imageFrame
    }

    override func titleRectForContentRect(contentRect:CGRect) -> CGRect {
        var titleFrame = super.titleRectForContentRect(contentRect)
        if (self.currentImage != nil) {
            titleFrame.origin.x = CGRectGetMinX(super.imageRectForContentRect(contentRect))
        }
        return titleFrame
    }
}

同样值得注意的是，它处理相当好图像和标题插入。

灵感来自jasongregori的回答;)

我最终创建了一个自定义按钮，允许从检查器设置图像。下面是我的代码:

import UIKit

@IBDesignable
class CustomButton: UIButton {

    @IBInspectable var leftImage: UIImage? = nil
    @IBInspectable var gapPadding: CGFloat = 0

    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        setup()
    }

    func setup() {

        if(leftImage != nil) {
            let imageView = UIImageView(image: leftImage)
            imageView.translatesAutoresizingMaskIntoConstraints = false

            addSubview(imageView)

            let length = CGFloat(16)
            titleEdgeInsets.left += length

            NSLayoutConstraint.activate([
                imageView.leadingAnchor.constraint(equalTo: self.leadingAnchor, constant: gapPadding),
                imageView.centerYAnchor.constraint(equalTo: self.titleLabel!.centerYAnchor, constant: 0),
                imageView.widthAnchor.constraint(equalToConstant: length),
                imageView.heightAnchor.constraint(equalToConstant: length)
            ])
        }
    }
}

你可以从检查器中调整空白填充的值来调整文本和图像之间的间距。

PS:使用了一些来自@Mark Hennings答案的代码部分

由于转换解决方案在iOS 11中不起作用，我决定编写一种新的方法。

调整按钮semanticContentAttribute可以让我们很好地将图像放到右边，而不必在文本更改时重新布局。因此它是理想溶液。然而，我仍然需要RTL的支持。事实上，一个应用程序不能改变它的布局方向在同一会话解决这个问题很容易。

话虽如此，它还是相当直截了当的。

extension UIButton {
    func alignImageRight() {
        if UIApplication.shared.userInterfaceLayoutDirection == .leftToRight {
            semanticContentAttribute = .forceRightToLeft
        }
        else {
            semanticContentAttribute = .forceLeftToRight
        }
    }
}