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
        }
    }
}

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)
    }
}

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)

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);

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+

在Piotr Tomasik的优雅解决方案的基础上:如果你想在按钮标签和图像之间有一点间距，那么包括在你的边缘嵌入如下(复制我的代码在这里完美地为我工作):

    CGFloat spacing          = 3;
    CGFloat insetAmount      = 0.5 * spacing;

    // First set overall size of the button:
    button.contentEdgeInsets = UIEdgeInsetsMake(0, insetAmount, 0, insetAmount);
    [button sizeToFit];

    // Then adjust title and image insets so image is flipped to the right and there is spacing between title and image:
    button.titleEdgeInsets   = UIEdgeInsetsMake(0, -button.imageView.frame.size.width - insetAmount, 0,  button.imageView.frame.size.width  + insetAmount);
    button.imageEdgeInsets   = UIEdgeInsetsMake(0, button.titleLabel.frame.size.width + insetAmount, 0, -button.titleLabel.frame.size.width - insetAmount);

感谢Piotr的解决方案!

Erik