要识别iPhone 4S，只需检查以下内容:

var isIphone4S: Bool {

    let width = UIScreen.main.bounds.size.width
    let height = UIScreen.main.bounds.size.height
    let proportions = width > height ? width / height : height / width

    return proportions == 1.5 && UIDevice.current.model == "iPhone"
}

Dutchie432和Brian Robbins提供了很好的解决方案。但还有一款型号没有推出，那就是Verizon的iPhone 4。这是缺失的一行。

if ([platform isEqualToString:@"iPhone3,2"])    return @"iPhone 4"; //Verizon

回答在Swift 3，

struct DeviceInformation {
    // UIDevice.current.model's value is "iPhone" or "iPad"，which does not include details; the following "model" is detailed, such as, iPhone7,1 is actually iPhone 6 plus
    static let model: String = {
        var size = 0
        sysctlbyname("hw.machine", nil, &size, nil, 0)
        var machine = [CChar](repeating: 0,  count: Int(size))
        sysctlbyname("hw.machine", &machine, &size, nil, 0)
        return String(cString: machine)
    }()

    static let uuid = UIDevice.current.identifierForVendor?.uuidString ?? ""
    static let idForAdService = ASIdentifierManager.shared().advertisingIdentifier.uuidString

    static func diviceTypeReadableName() -> String {
        switch model {
        case "iPhone1,1":   return "iPhone 1G"
        case "iPhone1,2":   return "iPhone 3G"
        case "iPhone2,1":   return "iPhone 3GS"
        case "iPhone3,1":   return "iPhone 4"
        case "iPhone3,3":   return "iPhone 4 (Verizon)"
        case "iPhone4,1":   return "iPhone 4S"
        case "iPhone5,1":   return "iPhone 5 (GSM)"
        case "iPhone5,2":   return "iPhone 5 (GSM+CDMA)"
        case "iPhone5,3":   return "iPhone 5c (GSM)"
        case "iPhone5,4":   return "iPhone 5c (GSM+CDMA)"
        case "iPhone6,1":   return "iPhone 5s (GSM)"
        case "iPhone6,2":   return "iPhone 5s (GSM+CDMA)"
        case "iPhone7,2":   return "iPhone 6"
        case "iPhone7,1":   return "iPhone 6 Plus"
        case "iPhone8,1":   return "iPhone 6s"
        case "iPhone8,2":   return "iPhone 6s Plus"
        case "iPhone8,4":   return "iPhone SE"
        case "iPhone9,1":   return "iPhone 7"
        case "iPhone9,3":   return "iPhone 7"
        case "iPhone9,2":   return "iPhone 7 Plus"
        case "iPhone9,4":   return "iPhone 7 Plus"
        case "iPod1,1":     return "iPod Touch 1G"
        case "iPod2,1":     return "iPod Touch 2G"
        case "iPod3,1":     return "iPod Touch 3G"
        case "iPod4,1":     return "iPod Touch 4G"
        case "iPod5,1":     return "iPod Touch 5G"
        case "iPod7,1":     return "iPod Touch 6G"
        case "iPad1,1":     return "iPad 1G"
        case "iPad2,1":     return "iPad 2 (Wi-Fi)"
        case "iPad2,2":     return "iPad 2 (GSM)"
        case "iPad2,3":     return "iPad 2 (CDMA)"
        case "iPad2,4":     return "iPad 2 (Wi-Fi)"
        case "iPad2,5":     return "iPad Mini (Wi-Fi)"
        case "iPad2,6":     return "iPad Mini (GSM)"
        case "iPad2,7":     return "iPad Mini (GSM+CDMA)"
        case "iPad3,1":     return "iPad 3 (Wi-Fi)"
        case "iPad3,2":     return "iPad 3 (GSM+CDMA)"
        case "iPad3,3":     return "iPad 3 (GSM)"
        case "iPad3,4":     return "iPad 4 (Wi-Fi)"
        case "iPad3,5":     return "iPad 4 (GSM)"
        case "iPad3,6":     return "iPad 4 (GSM+CDMA)"
        case "iPad4,1":     return "iPad Air (Wi-Fi)"
        case "iPad4,2":     return "iPad Air (Cellular)"
        case "iPad4,3":     return "iPad Air (China)"
        case "iPad4,4":     return "iPad Mini 2G (Wi-Fi)"
        case "iPad4,5":     return "iPad Mini 2G (Cellular)"
        case "iPad4,6":     return "iPad Mini 2G (China)"
        case "iPad4,7":     return "iPad Mini 3 (Wi-Fi)"
        case "iPad4,8":     return "iPad Mini 3 (Cellular)"
        case "iPad4,9":     return "iPad Mini 3 (China)"
        case "iPad5,1":     return "iPad Mini 4 (Wi-Fi)"
        case "iPad5,2":     return "iPad Mini 4 (Cellular)"
        case "iPad5,3":     return "iPad Air 2 (Wi-Fi)"
        case "iPad5,4":     return "iPad Air 2 (Cellular)"
        case "iPad6,3":     return "iPad Pro 9.7' (Wi-Fi)"
        case "iPad6,4":     return "iPad Pro 9.7' (Cellular)"
        case "iPad6,7":     return "iPad Pro 12.9' (Wi-Fi)"
        case "iPad6,8":     return "iPad Pro 12.9' (Cellular)"
        case "AppleTV2,1":  return "Apple TV 2G"
        case "AppleTV3,1":  return "Apple TV 3"
        case "AppleTV3,2":  return "Apple TV 3 (2013)"
        case "AppleTV5,3":  return "Apple TV 4"
        case "Watch1,1":    return "Apple Watch Series 1 (38mm, S1)"
        case "Watch1,2":    return "Apple Watch Series 1 (42mm, S1)"
        case "Watch2,6":    return "Apple Watch Series 1 (38mm, S1P)"
        case "Watch2,7":    return "Apple Watch Series 1 (42mm, S1P)"
        case "Watch2,3":    return "Apple Watch Series 2 (38mm, S2)"
        case "Watch2,4":    return "Apple Watch Series 2 (42mm, S2)"
        case "i386":        return "Simulator"
        case "x86_64":      return "Simulator"

        default:
            return ""
        }
    }
}

以下是新模型的小更新:

- (NSString *) platformString{
    NSString *platform = [self platform];
    if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 1G";
    if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";
    if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";
    if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";
    if ([platform isEqualToString:@"iPod1,1"])   return @"iPod Touch 1G";
    if ([platform isEqualToString:@"iPod2,1"])   return @"iPod Touch 2G";
    if ([platform isEqualToString:@"iPod3,1"])   return @"iPod Touch 3G";
    if ([platform isEqualToString:@"i386"])   return @"iPhone Simulator";
    return platform;
}

的可能值

[[UIDevice currentDevice] model];

是iPod touch, iPhone, iPhone模拟器，iPad, iPad模拟器

如果你想知道iOS正在破坏哪些硬件，比如iPhone3, iPhone4, iPhone5等，下面是代码

注意:下面的代码可能不包含所有设备的字符串，我和其他人在GitHub上维护相同的代码，所以请从那里获取最新的代码

Objective-C: GitHub/DeviceUtil

吉hub /恶魔大师

#include <sys/types.h>
#include <sys/sysctl.h>

- (NSString*)hardwareDescription {
    NSString *hardware = [self hardwareString];
    if ([hardware isEqualToString:@"iPhone1,1"]) return @"iPhone 2G";
    if ([hardware isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";
    if ([hardware isEqualToString:@"iPhone3,1"]) return @"iPhone 4";
    if ([hardware isEqualToString:@"iPhone4,1"]) return @"iPhone 4S";
    if ([hardware isEqualToString:@"iPhone5,1"]) return @"iPhone 5";
    if ([hardware isEqualToString:@"iPod1,1"]) return @"iPodTouch 1G";
    if ([hardware isEqualToString:@"iPod2,1"]) return @"iPodTouch 2G";
    if ([hardware isEqualToString:@"iPad1,1"]) return @"iPad";
    if ([hardware isEqualToString:@"iPad2,6"]) return @"iPad Mini";
    if ([hardware isEqualToString:@"iPad4,1"]) return @"iPad Air WIFI";
    //there are lots of other strings too, checkout the github repo
    //link is given at the top of this answer

    if ([hardware isEqualToString:@"i386"]) return @"Simulator";
    if ([hardware isEqualToString:@"x86_64"]) return @"Simulator";

    return nil;
}

- (NSString*)hardwareString {
    size_t size = 100;
    char *hw_machine = malloc(size);
    int name[] = {CTL_HW,HW_MACHINE};
    sysctl(name, 2, hw_machine, &size, NULL, 0);
    NSString *hardware = [NSString stringWithUTF8String:hw_machine];
    free(hw_machine);
    return hardware;
}

我想添加一个私有API来检索设备的正面和外壳颜色:

UIDevice *device = [UIDevice currentDevice];
SEL selector = NSSelectorFromString([device.systemVersion hasPrefix:@"7"] ? @"_deviceInfoForKey:" :  @"deviceInfoForKey:");
if ([device respondsToSelector:selector]) {
    NSLog(@"DeviceColor: %@ DeviceEnclosureColor: %@", [device performSelector:selector withObject:@"DeviceColor"], [device performSelector:selector withObject:@"DeviceEnclosureColor"]);
}

我在博客上写过这方面的文章，并提供了一个示例应用程序:

http://www.futuretap.com/blog/device-colors/