约束条件呢?与semanticContentAttribute不同，它们不会改变语义。也许是这样的:

 button.rightAnchorconstraint(equalTo: button.rightAnchor).isActive = true

或者在Objective-C中:

[button.imageView.rightAnchor constraintEqualToAnchor:button.rightAnchor].isActive = YES;

警告:未经测试，iOS 9+

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)
          }
        }
     }

子类化和覆盖layoutSubviews可能是你最好的方法。

引用自:iPhone UIButton -图像位置

swift 3.0迁移 jasongregori给出的解

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
        }

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)

从2016年1月开始，所有这些答案都是不必要的。在接口构建器中，将视图语义设置为强制从右向左，或者如果你更喜欢编程的方式，semanticContentAttribute = . forcerighttolefleft这将导致图像出现在文本的右侧。