最简单的解决方案:

iOS 10及以上版本，Swift:

button.transform = CGAffineTransform(scaleX: -1.0, y: 1.0)
button.titleLabel?.transform = CGAffineTransform(scaleX: -1.0, y: 1.0)
button.imageView?.transform = CGAffineTransform(scaleX: -1.0, y: 1.0)

在iOS 10之前，Swift/Obj-C:

button.transform = CGAffineTransformMakeScale(-1.0, 1.0);
button.titleLabel.transform = CGAffineTransformMakeScale(-1.0, 1.0);
button.imageView.transform = CGAffineTransformMakeScale(-1.0, 1.0);

iOS 9及以上版本，Swift:(推荐)

button.semanticContentAttribute = .forceRightToLeft

在尝试了互联网上的多种解决方案后，我没有达到确切的要求。所以我最终编写了自定义实用程序代码。在将来帮助别人。 在swift 4.2上测试

// This function should be called in/after viewDidAppear to let view render
    func addArrowImageToButton(button: UIButton, arrowImage:UIImage = #imageLiteral(resourceName: "my_image_name") ) {
        let btnSize:CGFloat = 32
        let imageView = UIImageView(image: arrowImage)
        let btnFrame = button.frame
        imageView.frame = CGRect(x: btnFrame.width-btnSize-8, y: btnFrame.height/2 - btnSize/2, width: btnSize, height: btnSize)
        button.addSubview(imageView)
        //Imageview on Top of View
        button.bringSubviewToFront(imageView)
    }

Swift 4 & 5

改变UIButton图像的方向(RTL和LTR)

extension UIButton {
    func changeDirection(){
       isArabic ? (self.contentHorizontalAlignment = .right) : (self.contentHorizontalAlignment = .left)
        // left-right margin 
        self.imageEdgeInsets = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
        self.titleEdgeInsets = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
    }
}

把@Piotr的答案变成了一个Swift扩展。请确保在调用此函数之前设置好图像和标题，以便按钮大小适当。

 extension UIButton {
    
    /// Makes the ``imageView`` appear just to the right of the ``titleLabel``.
    func alignImageRight() {
        if let titleLabel = self.titleLabel, imageView = self.imageView {
            // Force the label and image to resize.
            titleLabel.sizeToFit()
            imageView.sizeToFit()
            imageView.contentMode = .ScaleAspectFit
            
            // Set the insets so that the title appears to the left and the image appears to the right. 
            // Make the image appear slightly off the top/bottom edges of the button.
            self.titleEdgeInsets = UIEdgeInsets(top: 0, left: -1 * imageView.frame.size.width,
                bottom: 0, right: imageView.frame.size.width)
            self.imageEdgeInsets = UIEdgeInsets(top: 4, left: titleLabel.frame.size.width,
                bottom: 4, right: -1 * titleLabel.frame.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;)

如果这需要在UIBarButtonItem中完成，则应该使用额外的视图包装 这是可行的

let view = UIView()
let button = UIButton()
button.setTitle("Skip", for: .normal)
button.setImage(#imageLiteral(resourceName:"forward_button"), for: .normal)
button.semanticContentAttribute = .forceRightToLeft
button.sizeToFit()
view.addSubview(button)
view.frame = button.bounds
navigationItem.rightBarButtonItem = UIBarButtonItem(customView: view)

这行不通

let button = UIButton()
button.setTitle("Skip", for: .normal)
button.setImage(#imageLiteral(resourceName:"forward_button"), for: .normal)
button.semanticContentAttribute = .forceRightToLeft
button.sizeToFit()
navigationItem.rightBarButtonItem = UIBarButtonItem(customView: button)