iOS 13新特性

iOS 13新特性

1. view controller present

   iOS 13之后，present的modalPresentationStyle方式变成了automatic, 呈现的方式并不是全屏显示，而是会顶部留白，默认下拉可以dismiss。

   如果想要全屏显示可以如下:

    vc.modalPresentationStyle = .fullScreen
    self.present(vc, animated: true)
   

2. 禁用暗黑模式

   将info.plist的UserInterfaceStyle的value设置为light

3. iOS 13中禁用KVC调用私有属性

   比如:

    let searchField: UITextField = self.searchBar.value(forKey: "")
   	let placeHolderLabel: UILabel = searchField.value(forKey: "placeHolderLabel")
    placeHolderLabel.textColor = UIColor.red
   

   上面这个会引起crash，正确的做法：

    let textField = self.searchBar.searchTextField // in iOS 13
    let attr = NSMutableAttributedString(string: "aaaa")
    textField?.attributedPlaceholder = attr
   

4. keyWindow

   iOS 13为了适配多屛，如果是多屏的应用的话，那么:

    UIApplication.shared.keyWindow 
   

   就不应该再被使用

    @available(iOS, introduced: 2.0, deprecated: 13.0, message: "Should not be used for applications that support multiple scenes as it returns a key window across all connected scenes")
    open var keyWindow: UIWindow? { get }
   

   取而代之的应该是:

    UIApplication.shared.windows.filter { $0.isKeyWindow }.first