在看完所有的答案后，我最后是这么做的:

解决方案(兼容Swift 4.1)

extension UIDevice {
    static var isIphoneX: Bool {
        var modelIdentifier = ""
        if isSimulator {
            modelIdentifier = ProcessInfo.processInfo.environment["SIMULATOR_MODEL_IDENTIFIER"] ?? ""
        } else {
            var size = 0
            sysctlbyname("hw.machine", nil, &size, nil, 0)
            var machine = [CChar](repeating: 0, count: size)
            sysctlbyname("hw.machine", &machine, &size, nil, 0)
            modelIdentifier = String(cString: machine)
        }

        return modelIdentifier == "iPhone10,3" || modelIdentifier == "iPhone10,6"
    }

    static var isSimulator: Bool {
        return TARGET_OS_SIMULATOR != 0
    }
}

Use

if UIDevice.isIphoneX {
    // is iPhoneX
} else {
    // is not iPhoneX
}

Note

Pre Swift 4.1你可以检查应用程序是否在模拟器上运行，就像这样:

TARGET_OS_SIMULATOR != 0

从Swift 4.1开始，你可以使用目标环境平台条件检查应用程序是否在模拟器上运行:

#if targetEnvironment(simulator)
    return true
#else
    return false
#endif

(旧的方法仍然有效，但这个新方法更经得起未来的考验)

您需要根据实际需要对iPhone X进行不同的检测。

用于处理顶级(状态栏，导航栏)等。

class var hasTopNotch: Bool {
    if #available(iOS 11.0, tvOS 11.0, *) {
        // with notch: 44.0 on iPhone X, XS, XS Max, XR.
        // without notch: 24.0 on iPad Pro 12.9" 3rd generation, 20.0 on iPhone 8 on iOS 12+.
        return UIApplication.shared.delegate?.window??.safeAreaInsets.top ?? 0 > 24
    }
    return false
}

用于处理底部home指示器(标签栏)等。

class var hasBottomSafeAreaInsets: Bool {
    if #available(iOS 11.0, tvOS 11.0, *) {
        // with home indicator: 34.0 on iPhone X, XS, XS Max, XR.
        // with home indicator: 20.0 on iPad Pro 12.9" 3rd generation.
        return UIApplication.shared.delegate?.window??.safeAreaInsets.bottom ?? 0 > 0
    }
    return false
}

背景大小，全屏功能等。

class var isIphoneXOrBigger: Bool {
    // 812.0 on iPhone X, XS.
    // 896.0 on iPhone XS Max, XR.
    return UIScreen.main.bounds.height >= 812
}

注意:最终将其与UIDevice.current.userInterfaceIdiom == .phone混合 注意:此方法需要有一个LaunchScreen故事板或适当的launchimage

背景比例，滚动功能等。

class var isIphoneXOrLonger: Bool {
    // 812.0 / 375.0 on iPhone X, XS.
    // 896.0 / 414.0 on iPhone XS Max, XR.
    return UIScreen.main.bounds.height / UIScreen.main.bounds.width >= 896.0 / 414.0
}

注意:此方法需要有一个LaunchScreen故事板或适当的launchimage

用于分析，统计，跟踪等。

获取机器标识符并将其与文档值进行比较:

class var isIphoneX: Bool {
    var size = 0
    sysctlbyname("hw.machine", nil, &size, nil, 0)
    var machine = [CChar](repeating: 0, count: size)
    sysctlbyname("hw.machine", &machine, &size, nil, 0)
    let model = String(cString: machine)
    return model == "iPhone10,3" || model == "iPhone10,6"
}

要将模拟器作为有效的iPhone X包含在分析中:

class var isIphoneX: Bool {
    let model: String
    if TARGET_OS_SIMULATOR != 0 {
        model = ProcessInfo.processInfo.environment["SIMULATOR_MODEL_IDENTIFIER"] ?? ""
    } else {
        var size = 0
        sysctlbyname("hw.machine", nil, &size, nil, 0)
        var machine = [CChar](repeating: 0, count: size)
        sysctlbyname("hw.machine", &machine, &size, nil, 0)
        model = String(cString: machine)
    }
    return model == "iPhone10,3" || model == "iPhone10,6"
}

要包括iPhone XS、XS Max和XR，只需查找以“iPhone11”开头的型号:

return model == "iPhone10,3" || model == "iPhone10,6" || model.starts(with: "iPhone11,")

支持faceID

import LocalAuthentication
/// will fail if user denies canEvaluatePolicy(_:error:)
class var canUseFaceID: Bool {
    if #available(iOS 11.0, *) {
        return LAContext().biometryType == .typeFaceID
    }
    return false
}

- (BOOL)isIphoneX {
    if (@available(iOS 11.0, *)) {
        UIWindow *window = UIApplication.sharedApplication.keyWindow;
        CGFloat topPadding = window.safeAreaInsets.top;
        if(topPadding>0) {
            return YES;
        }
        else {
            return NO;
        }
    }
    else {
        return NO;
    }
}

检测设备是否为iPhone X的最佳和最简单的方法是，

https://github.com/stephanheilner/UIDevice-DisplayName

var systemInfo = utsname()
uname(&systemInfo)
let machineMirror = Mirror(reflecting: systemInfo.machine)
let identifier = machineMirror.children.reduce("") { identifier, element in
guard let value = element.value as? Int8 , value != 0 else { return identifier}
            return identifier + String(UnicodeScalar(UInt8(value)))}

标识符是iPhone10,3或者iPhone10,6对于iPhone X。

使用简单的方法检测任何设备。像下面,

func isPhoneDevice() -> Bool {
    return UIDevice.current.userInterfaceIdiom == .phone
}

func isDeviceIPad() -> Bool {
    return UIDevice.current.userInterfaceIdiom == .pad
}

func isPadProDevice() -> Bool {
    let SCREEN_WIDTH: CGFloat = UIScreen.main.bounds.size.width
    let SCREEN_HEIGHT: CGFloat = UIScreen.main.bounds.size.height
    let SCREEN_MAX_LENGTH: CGFloat = fmax(SCREEN_WIDTH, SCREEN_HEIGHT)

    return UIDevice.current.userInterfaceIdiom == .pad && SCREEN_MAX_LENGTH == 1366.0
}

func isPhoneXandXSDevice() -> Bool {
    let SCREEN_WIDTH = CGFloat(UIScreen.main.bounds.size.width)
    let SCREEN_HEIGHT = CGFloat(UIScreen.main.bounds.size.height)
    let SCREEN_MAX_LENGTH: CGFloat = fmax(SCREEN_WIDTH, SCREEN_HEIGHT)

    return UIDevice.current.userInterfaceIdiom == .phone && SCREEN_MAX_LENGTH == 812.0
}

func isPhoneXSMaxandXRDevice() -> Bool {
    let SCREEN_WIDTH = CGFloat(UIScreen.main.bounds.size.width)
    let SCREEN_HEIGHT = CGFloat(UIScreen.main.bounds.size.height)
    let SCREEN_MAX_LENGTH: CGFloat = fmax(SCREEN_WIDTH, SCREEN_HEIGHT)

    return UIDevice.current.userInterfaceIdiom == .phone && SCREEN_MAX_LENGTH == 896.0
}

像这样叫，

if isPhoneDevice() {
     // Your code
}

我试图使工作之前的答复，他们都没有为我工作。所以我为SwiftUI找到了一个解决方案。创建名为UIDevice+Notch.swift的文件

其内容:

extension UIDevice {
    var hasNotch: Bool {
        let bottom = UIApplication.shared.keyWindow?.safeAreaInsets.bottom ?? 0
        return bottom > 0
    }
}

用法:

if UIDevice.current.hasNotch {
    //... consider notch 
} else {
    //... don't have to consider notch 
}