我认为它应该很好，如果这个宏将在设备和模拟器中工作，下面是解决方案。

#define IS_WIDESCREEN (fabs((double)[[UIScreen mainScreen]bounds].size.height - (double)568) < DBL_EPSILON)
#define IS_IPHONE (([[[UIDevice currentDevice] model] isEqualToString:@"iPhone"]) || ([[[UIDevice currentDevice] model] isEqualToString: @"iPhone Simulator"]))
#define IS_IPOD   ([[[UIDevice currentDevice]model] isEqualToString:@"iPod touch"])
#define IS_IPHONE_5 ((IS_IPHONE || IS_IPOD) && IS_WIDESCREEN)

在Swift, iOS 8+项目中，我喜欢在UIScreen上做一个扩展，比如:

extension UIScreen {

    var isPhone4: Bool {
        return self.nativeBounds.size.height == 960;
    }

    var isPhone5: Bool {
        return self.nativeBounds.size.height == 1136;
    }

    var isPhone6: Bool {
        return self.nativeBounds.size.height == 1334;
    }

    var isPhone6Plus: Bool {
        return self.nativeBounds.size.height == 2208;
    }

}

(注意:nativeBounds是以像素为单位)。

然后代码会是这样的:

if UIScreen.mainScreen().isPhone4 {
    // do smth on the smallest screen
}

因此，代码清楚地表明这是对主屏幕的检查，而不是对设备模型的检查。

if ((int)[[UIScreen mainScreen] bounds].size.height == 568)
{
    // This is iPhone 5 screen
} else {
    // This is iPhone 4 screen
}

依赖规模在很多层面上都是错误的。如果我们问系统呢?

- (NSString *) getDeviceModel
{
    struct utsname systemInfo;
    uname(&systemInfo);
    return [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding];
}

摘自《检测硬件类型的最佳方法，iPhone4还是iPhone5?》edzio27回答。

通过这种方式，您可以检测设备系列。

    #import <sys/utsname.h>
    NSString* deviceName()
    {
        struct utsname systemInformation;
        uname(&systemInformation);
        NSString *result = [NSString stringWithCString:systemInformation.machine
                                              encoding:NSUTF8StringEncoding];
        return result;
    }

    #define isIPhone5  [deviceName() rangeOfString:@"iPhone5,"].location != NSNotFound
    #define isIPhone5S [deviceName() rangeOfString:@"iPhone6,"].location != NSNotFound

用于检测所有版本的iPhone和iPad设备。

#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
#define IS_IPHONE_5 (IS_IPHONE && [[UIScreen mainScreen] bounds].size.height == 568.0)
#define IS_IPHONE_6 (IS_IPHONE && [[UIScreen mainScreen] bounds].size.height == 667.0)
#define IS_IPHONE_6_PLUS (IS_IPHONE && [[UIScreen mainScreen] bounds].size.height == 736.0)
#define IS_RETINA ([[UIScreen mainScreen] scale] == 2.0)