如何修复 - safeAreaLayoutGuide' 仅适用于 iOS 11.0 或更高版本

Question

在我的应用程序中出现此错误 -

safeAreaLayoutGuide' is only available on iOS 11.0 or newer

在此代码中，错误出现了 3 次。基本上在我使用 safeArea 的每一行中。

NSLayoutConstraint.activate([
        stackViewBottomConstrols.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
        stackViewBottomConstrols.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
        stackViewBottomConstrols.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
        stackViewBottomConstrols.heightAnchor.constraint(equalToConstant: 50)
        ])

我可以检查IOS 11 是否可用并运行此代码并在else 语句中添加另一个代码，使用相同的代码但没有safeArea。这是否会显示与if 语句中相同的视图。如果没有，还有其他解决方案吗？

此代码可以在没有 IOS 11 的设备上运行吗？ -

        if #available(iOS 11.0, *) {
        NSLayoutConstraint.activate([
            stackViewBottomConstrols.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
            stackViewBottomConstrols.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
            stackViewBottomConstrols.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
            stackViewBottomConstrols.heightAnchor.constraint(equalToConstant: 50)
            ])
    } else {
        NSLayoutConstraint.activate([
            stackViewBottomConstrols.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            stackViewBottomConstrols.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            stackViewBottomConstrols.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            stackViewBottomConstrols.heightAnchor.constraint(equalToConstant: 50)
            ])
    }

Answer 1

safeAreaLayoutGuide 只是顶部、底部布局指南的替代品，并添加了前导、尾随 - 当然你的代码很好，这是在代码中创建约束以支持的唯一方法IOS 11 及更低版本，但仅用于切换无关紧要的约束

stackViewBottomConstrols.heightAnchor.constraint(equalToConstant: 50)

变成这样

if #available(iOS 11.0, *) {
    NSLayoutConstraint.activate([
        stackViewBottomConstrols.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
        stackViewBottomConstrols.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
        stackViewBottomConstrols.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor)
     ])
} else {
    NSLayoutConstraint.activate([
        stackViewBottomConstrols.bottomAnchor.constraint(equalTo: self.bottomLayoutGuide.topAnchor),
        stackViewBottomConstrols.leadingAnchor.constraint(equalTo: view.leadingAnchor),
        stackViewBottomConstrols.trailingAnchor.constraint(equalTo: view.trailingAnchor)
     ])
      
}

Answer 2

如果您希望尽可能保持一致，请在 pre-iOS-11 块中，将 view.bottomAnchor 替换为 bottomLayoutGuide.topAnchor。在 iOS 11 之前，仍然有 topLayoutGuide 和 bottomLayoutGuide 帮助程序员考虑导航栏、标签栏等。否则，我觉得很好！

编辑：结果代码：

if #available(iOS 11.0, *) {
    NSLayoutConstraint.activate([
        stackViewBottomConstrols.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
        stackViewBottomConstrols.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
        stackViewBottomConstrols.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
        ])
} else {
    NSLayoutConstraint.activate([
        stackViewBottomConstrols.bottomAnchor.constraint(equalTo: bottomLayoutGuide.topAnchor),
        stackViewBottomConstrols.leadingAnchor.constraint(equalTo: view.leadingAnchor),
        stackViewBottomConstrols.trailingAnchor.constraint(equalTo: view.trailingAnchor),
        ])
}
// This one doesn't care which iOS version it is
stackViewBottomConstrols.heightAnchor.constraint(equalToConstant: 50)