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

扩展的方法

使用扩展设置图像右侧自定义偏移

   extension UIButton {
    func addRightImage(image: UIImage, offset: CGFloat) {
        self.setImage(image, for: .normal)
        self.imageView?.translatesAutoresizingMaskIntoConstraints = false
        self.imageView?.centerYAnchor.constraint(equalTo: self.centerYAnchor, constant: 0.0).isActive = true
        self.imageView?.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -offset).isActive = true
    }
}

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
        }

这里提到的解决方案停止工作，一旦我启用自动布局。我不得不提出我自己的想法:

子类UIButton和覆盖layoutSubviews方法:

//
//  MIThemeButtonImageAtRight.m
//  Created by Lukasz Margielewski on 7/9/13.
//

#import "MIThemeButtonImageAtRight.h"

static CGRect CGRectByApplyingUIEdgeInsets(CGRect frame, UIEdgeInsets insets);

@implementation MIThemeButtonImageAtRight

- (void)layoutSubviews
{
    [super layoutSubviews];

    CGRect contentFrame = CGRectByApplyingUIEdgeInsets(self.bounds, self.contentEdgeInsets);

    CGRect frameIcon = self.imageView.frame;
    CGRect frameText = self.titleLabel.frame;

    frameText.origin.x = CGRectGetMinX(contentFrame) + self.titleEdgeInsets.left;
    frameIcon.origin.x = CGRectGetMaxX(contentFrame) - CGRectGetWidth(frameIcon);

    self.imageView.frame = frameIcon;
    self.titleLabel.frame = frameText;
}

@end

static CGRect CGRectByApplyingUIEdgeInsets(CGRect frame, UIEdgeInsets insets){

    CGRect f = frame;

    f.origin.x += insets.left;
    f.size.width -= (insets.left + insets.right);
    f.origin.y += (insets.top);
    f.size.height -= (insets.top + insets.bottom);

    return f;

}

结果:

要在UIButton内右对齐图像，请尝试下面的代码

btn.contentHorizontalAlignment = .right