UIToolbar强制左到右语义无效，RTL语言下按钮错乱求助

以下是几个可行的解决方案，按优先级排序：

1. 单独设置每个UIBarButtonItem的语义属性 #

UIToolbar的语义设置不会自动传递给内部的UIBarButtonItem，因此需要给每个按钮单独指定强制从左到右的语义：

// 假设你已创建好三个按钮和弹性间隔项
prevButton.semanticContentAttribute = .forceLeftToRight
todayButton.semanticContentAttribute = .forceLeftToRight
nextButton.semanticContentAttribute = .forceLeftToRight

// 保持原顺序设置toolbar items
toolbar.items = [prevButton, flexibleSpace, todayButton, flexibleSpace, nextButton]
toolbar.semanticContentAttribute = .forceLeftToRight

如果是在Storyboard中创建的按钮，可选中每个UIBarButtonItem，在Attributes Inspector里找到Semantic选项，设置为Force Left-to-Right。

2. 使用自定义UIButton作为BarButtonItem的自定义视图 #

如果系统默认的UIBarButtonItem语义设置不生效，改用自定义UIButton来精确控制行为：

// 创建"上一天"按钮
let prevBtn = UIButton(type: .system)
prevBtn.setTitle("上一天", for: .normal)
prevBtn.addTarget(self, action: #selector(prevDay), for: .touchUpInside)
prevBtn.semanticContentAttribute = .forceLeftToRight
let prevBarItem = UIBarButtonItem(customView: prevBtn)

// 创建"下一天"按钮
let nextBtn = UIButton(type: .system)
nextBtn.setTitle("下一天", for: .normal)
nextBtn.addTarget(self, action: #selector(nextDay), for: .touchUpInside)
nextBtn.semanticContentAttribute = .forceLeftToRight
let nextBarItem = UIBarButtonItem(customView: nextBtn)

// 创建"今天"按钮
let todayBtn = UIButton(type: .system)
todayBtn.setTitle("今天", for: .normal)
todayBtn.addTarget(self, action: #selector(goToToday), for: .touchUpInside)
todayBtn.semanticContentAttribute = .forceLeftToRight
let todayBarItem = UIBarButtonItem(customView: todayBtn)

// 设置间隔项
let flexibleSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)

// 组装toolbar items
toolbar.items = [prevBarItem, flexibleSpace, todayBarItem, flexibleSpace, nextBarItem]
toolbar.semanticContentAttribute = .forceLeftToRight

3. 手动适配RTL环境下的items顺序 #

如果上述方法都无效，可直接根据布局方向手动调整items的排列顺序，同时处理方向变化的情况：

// 定义基础items数组
let baseItems = [prevButton, flexibleSpace, todayButton, flexibleSpace, nextButton]
// 定义RTL下反转后的items数组
let rtlItems = [nextButton, flexibleSpace, todayButton, flexibleSpace, prevButton]

// 设置初始items
toolbar.items = UIApplication.shared.userInterfaceLayoutDirection == .rightToLeft ? rtlItems : baseItems
toolbar.semanticContentAttribute = .forceLeftToRight

// 注册布局方向变化通知，实时更新items
NotificationCenter.default.addObserver(self, selector: #selector(updateToolbarItems), name: UIApplication.userInterfaceLayoutDirectionDidChangeNotification, object: nil)

// 通知回调方法
@objc private func updateToolbarItems() {
    let isRTL = UIApplication.shared.userInterfaceLayoutDirection == .rightToLeft
    toolbar.items = isRTL ? rtlItems : baseItems
}

注意：记得在视图销毁时移除通知观察者，避免内存泄漏。

内容的提问来源于stack exchange，提问作者Ely Jacobi