如何为导航控制器添加右侧导航栏按钮并调整其大小与位置

如何为导航控制器内的视图控制器添加带图片的右侧导航栏按钮？我尝试了以下代码：

let image = UIImage(named: "save") // Use your custom image or SF Symbols
let button = UIBarButtonItem(image: image, style: .plain, target: self, action: #selector(addToLibraryTapped))
navigationItem.rightBarButtonItem = button

但实现效果中按钮尺寸偏大，且未靠最右侧显示，需要调整这两个问题。

1. 缩小导航栏按钮尺寸 #

UIBarButtonItem默认会放大图片，可通过两种方式调整：

• 自定义图片内边距：

  let image = UIImage(named: "save")?.withRenderingMode(.alwaysOriginal)
  let button = UIBarButtonItem(image: image, style: .plain, target: self, action: #selector(addToLibraryTapped))
  // 设置内边距压缩显示大小，数值可按需调整
  button.imageInsets = UIEdgeInsets(top: 8, left: 8, bottom: 8, right: 8)
  navigationItem.rightBarButtonItem = button
  

• 若使用SF Symbols，直接指定符号配置：

  let symbolConfig = UIImage.SymbolConfiguration(pointSize: 16, weight: .medium)
  let image = UIImage(systemName: "square.and.arrow.down", withConfiguration: symbolConfig)
  let button = UIBarButtonItem(image: image, style: .plain, target: self, action: #selector(addToLibraryTapped))
  navigationItem.rightBarButtonItem = button
  

2. 让按钮紧贴导航栏右侧 #

导航栏默认会给右侧按钮预留边距，通过自定义UIButton作为UIBarButtonItem的自定义视图，可消除边距：

let customButton = UIButton(type: .system)
customButton.setImage(UIImage(named: "save")?.withRenderingMode(.alwaysOriginal), for: .normal)
customButton.addTarget(self, action: #selector(addToLibraryTapped), for: .touchUpInside)
// 自定义按钮尺寸，控制显示大小
customButton.frame = CGRect(x: 0, y: 0, width: 24, height: 24)
let barButton = UIBarButtonItem(customView: customButton)
navigationItem.rightBarButtonItem = barButton

这种方式能完全控制按钮位置，使其紧贴导航栏右侧边缘。

内容的提问来源于stack exchange，提问作者Chris Hansen