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)

针对SDK和OS的任何组合进行测试和设计:

斯威夫特

增加了iPad类型。iPad 2和iPad mini是非视网膜iPad。而iPad Mini 2及以上，iPad 3,4, iPad Air, Air 2, Air 3和iPad Pro 9.7具有相同的1024逻辑分辨率。iPad Pro的maxLength为1366。参考

import UIKit

public enum DisplayType {
    case unknown
    case iphone4
    case iphone5
    case iphone6
    case iphone6plus
    case iPadNonRetina
    case iPad
    case iPadProBig
    static let iphone7 = iphone6
    static let iphone7plus = iphone6plus
}

public final class Display {
    class var width:CGFloat { return UIScreen.main.bounds.size.width }
    class var height:CGFloat { return UIScreen.main.bounds.size.height }
    class var maxLength:CGFloat { return max(width, height) }
    class var minLength:CGFloat { return min(width, height) }
    class var zoomed:Bool { return UIScreen.main.nativeScale >= UIScreen.main.scale }
    class var retina:Bool { return UIScreen.main.scale >= 2.0 }
    class var phone:Bool { return UIDevice.current.userInterfaceIdiom == .phone }
    class var pad:Bool { return UIDevice.current.userInterfaceIdiom == .pad }
    class var carplay:Bool { return UIDevice.current.userInterfaceIdiom == .carPlay }
    class var tv:Bool { return UIDevice.current.userInterfaceIdiom == .tv }
    class var typeIsLike:DisplayType {
        if phone && maxLength < 568 {
            return .iphone4
        }
        else if phone && maxLength == 568 {
                return .iphone5
        }
        else if phone && maxLength == 667 {
            return .iphone6
        }
        else if phone && maxLength == 736 {
            return .iphone6plus
        }
        else if pad && !retina {
            return .iPadNonRetina
        }
        else if pad && retina && maxLength == 1024 {
            return .iPad
        }
        else if pad && maxLength == 1366 {
            return .iPadProBig
        }
        return .unknown
    }
}

看看它的实际应用 https://gist.github.com/hfossli/bc93d924649de881ee2882457f14e346

注意:例如，如果iPhone 6处于放大模式，UI就是放大版的iPhone 5。这些功能不是决定设备类型，而是决定显示模式，因此iPhone 5是本例中的理想结果。

objective - c

#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
#define IS_RETINA ([[UIScreen mainScreen] scale] >= 2.0)

#define SCREEN_WIDTH ([[UIScreen mainScreen] bounds].size.width)
#define SCREEN_HEIGHT ([[UIScreen mainScreen] bounds].size.height)
#define SCREEN_MAX_LENGTH (MAX(SCREEN_WIDTH, SCREEN_HEIGHT))
#define SCREEN_MIN_LENGTH (MIN(SCREEN_WIDTH, SCREEN_HEIGHT))
#define IS_ZOOMED (IS_IPHONE && SCREEN_MAX_LENGTH == 736.0)

#define IS_IPHONE_4_OR_LESS (IS_IPHONE && SCREEN_MAX_LENGTH < 568.0)
#define IS_IPHONE_5 (IS_IPHONE && SCREEN_MAX_LENGTH == 568.0)
#define IS_IPHONE_6 (IS_IPHONE && SCREEN_MAX_LENGTH == 667.0)
#define IS_IPHONE_6P (IS_IPHONE && SCREEN_MAX_LENGTH == 736.0)

用法:http://pastie.org/9687735

注意:例如，如果iPhone 6处于放大模式，UI就是放大版的iPhone 5。这些功能不是决定设备类型，而是决定显示模式，因此iPhone 5是本例中的理想结果。

这是我的cocos2d项目的宏。对于其他应用程序应该是一样的。

#define WIDTH_IPAD 1024
#define WIDTH_IPHONE_5 568
#define WIDTH_IPHONE_4 480
#define HEIGHT_IPAD 768
#define HEIGHT_IPHONE 320

#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)

//width is height!
#define IS_IPHONE_5 ( [ [ UIScreen mainScreen ] bounds ].size.height == WIDTH_IPHONE_5 )
#define IS_IPHONE_4 ( [ [ UIScreen mainScreen ] bounds ].size.height == WIDTH_IPHONE_4 )

#define cp_ph4(__X__, __Y__) ccp(cx_ph4(__X__), cy_ph4(__Y__))
#define cx_ph4(__X__) (IS_IPAD ? (__X__ * WIDTH_IPAD / WIDTH_IPHONE_4) : (IS_IPHONE_5 ? (__X__ * WIDTH_IPHONE_5 / WIDTH_IPHONE_4) : (__X__)))
#define cy_ph4(__Y__) (IS_IPAD ? (__Y__ * HEIGHT_IPAD / HEIGHT_IPHONE) : (__Y__))

#define cp_pad(__X__, __Y__) ccp(cx_pad(__X__), cy_pad(__Y__))
#define cx_pad(__X__) (IS_IPAD ? (__X__) : (IS_IPHONE_5 ? (__X__ * WIDTH_IPHONE_5 / WIDTH_IPAD) : (__X__ * WIDTH_IPHONE_4 / WIDTH_IPAD)))
#define cy_pad(__Y__) (IS_IPAD ? (__Y__) : (__Y__ * HEIGHT_IPHONE / HEIGHT_IPAD))

借用Samrat Mazumdar的回答，这里有一个估算设备屏幕大小的简单方法。它适用于最新的设备，但在未来的设备上可能会失败(正如所有猜测的方法一样)。如果设备正在镜像，它也会混淆(返回设备的屏幕大小，而不是镜像的屏幕大小)

#define SCREEN_SIZE_IPHONE_CLASSIC 3.5
#define SCREEN_SIZE_IPHONE_TALL 4.0
#define SCREEN_SIZE_IPAD_CLASSIC 9.7

+ (CGFloat)screenPhysicalSize
{
    if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
    {
        CGSize result = [[UIScreen mainScreen] bounds].size;
        if (result.height < 500)
            return SCREEN_SIZE_IPHONE_CLASSIC;  // iPhone 4S / 4th Gen iPod Touch or earlier
        else
            return SCREEN_SIZE_IPHONE_TALL;  // iPhone 5
    }
    else
    {
        return SCREEN_SIZE_IPAD_CLASSIC; // iPad
    }
} 

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。

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