- (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;
    }
}

#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
#define IS_IPHONE_X (IS_IPHONE && [[UIScreen mainScreen] bounds].size.height == 812.0f)

另一种可能是，在iOS 11和iOS 12上都能运行，因为iPhone X是唯一一款顶部有凹槽、嵌框为44的手机。这就是我在这里真正发现的:

objective - c:

    BOOL iPhoneX = NO;
    if (@available(iOS 11.0, *)) {
        UIWindow *mainWindow = [[[UIApplication sharedApplication] delegate] window];
        if (mainWindow.safeAreaInsets.top > 24.0) {
            iPhoneX = YES;
        }
    }

斯威夫特4:

/// Has safe area
///
/// with notch: 44.0 on iPhone X, XS, XS Max, XR.
///
/// without notch: 20.0 on iPhone 8 on iOS 12+.
///
static var hasSafeArea: Bool {
    guard #available(iOS 11.0, *), let topPadding = UIApplication.shared.keyWindow?.safeAreaInsets.top, topPadding > 24 else {
        return false
    }
    return true
}

当然，如果你是在横向，你可能需要检查左右安全区域的嵌入。

Edit: _window是AppDelegate的UIWindow，这个检查在应用didFinishLaunchingWithOptions中完成。

iOS 12的答案更新，以检查顶部>是否为24，而不是顶部> 0。

编辑:在模拟器中，您可以选择硬件，切换通话状态栏。这样做表明，在通话时，iOS 11的iPhone X或iOS 12的iPhone XS上的状态栏高度没有变化。在这两种情况下，改变的只是时间图标，它的背景都是绿色的。这是一张快照:

SWIFT 4+回答

iPhone X, XR, XS, XSMAX, 11 Pro, 11 Pro Max:

注:需实物设备进行测试

参考

 let deviceType = UIDevice.current.modelName
        switch deviceType {
        case "iPhone10,3", "iPhone10,6":
            print("iPhoneX")
        case "iPhone11,2":
            print("iPhone XS")
        case "iPhone11,4":
            print("iPhone XS Max")
        case "iPhone11,6":
            print("iPhone XS Max China")
        case "iPhone11,8":
            print("iPhone XR")
        case "iPhone12,3":
            print("iPhone 11 Pro")
        case "iPhone12,5":
            print("iPhone 11 Pro Max")
        default:
            break
}

extension UIDevice {
    var modelName: String {
        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)))
        }
        return identifier
    }
}

检查设备型号/机器名称，不要在你的代码中直接使用点/像素计数，这是硬代码，对设备硬件没有意义，设备型号是设备类型匹配的唯一标识符。

#import <sys/utsname.h>

NSString* deviceName()
{
    struct utsname systemInfo;
    uname(&systemInfo);

    return [NSString stringWithCString:systemInfo.machine
                          encoding:NSUTF8StringEncoding];
}

结果:

@"iPhone10,3" on iPhone X (CDMA)
@"iPhone10,6" on iPhone X (GSM)

参考这个答案。

完整的代码实现:

#import <sys/utsname.h>

NSString * GetDeviceModel(void)
{
    static dispatch_once_t onceToken;
    static NSString *strModelID = nil;

    dispatch_once(&onceToken, ^{
#if TARGET_IPHONE_SIMULATOR
        strModelID = NSProcessInfo.processInfo.environment[@"SIMULATOR_MODEL_IDENTIFIER"];
#else
        struct utsname systemInfo;

        uname(&systemInfo);
        strModelID = [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding];
#endif
    });

    return strModelID;
}

// See the `Hardware strings` in https://en.wikipedia.org/wiki/List_of_iOS_devices
BOOL IsiPhoneX(void)
{
    NSString *strModelID = GetDeviceModel();

    return [strModelID isEqualToString:@"iPhone10,3"] || [strModelID isEqualToString:@"iPhone10,6"];
}

BOOL IsNotchiPhone(void)
{
    NSArray<NSString *> *notchiModels = @[
        @"iPhone10,3", @"iPhone10,6", // iPhone X
        @"iPhone11,2", @"iPhone11,4", @"iPhone11,6", // iPhone XS (Max)
        @"iPhone11,8", // iPhone XR
        @"iPhone12,1", @"iPhone12,3", @"iPhone12,5", // iPhone 11 (Pro (Max))
        @"iPhone13,1", @"iPhone13,2", @"iPhone13,3", @"iPhone13,4", // iPhone 12 ([mini]|[Pro (Max)])
    ];

    return [notchiModels containsObject:GetDeviceModel()];
}

根据@saswanb的回复，这是Swift 4的版本:

var iphoneX = false
if #available(iOS 11.0, *) {
    if ((UIApplication.shared.keyWindow?.safeAreaInsets.top)! > CGFloat(0.0)) {
        iphoneX = true
    }
}