Question

在我的应用中，我有这个错误 -

safeAreaLayoutGuide' is only available on iOS 11.0 or newer

在此代码中，错误出现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)
        ])

我是否可以检查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，但代码相同但没有safeArea。这会显示与if语句中的视图相同的视图。如果没有，还有其他解决方案吗？

此代码是否适用于没有IOS 11的设备？ -

        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，增加了前导，尾随 - 当然你的代码很好用，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，但仅用于切换不重要的约束

  stackViewBottomConstrols.heightAnchor.constraint(equalToConstant: 50)

是这个

   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iOS-11之前的版块中，将view.bottomAnchor替换为bottomLayoutGuide.topAnchor。在iOS 11之前，仍有topLayoutGuide和bottomLayoutGuide来帮助程序员考虑导航栏，标签栏等。否则，对我来说看起来不错！

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)

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

2 个答案: