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

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))

+(BOOL)isDeviceiPhone5
{
    BOOL iPhone5 = FALSE;

    CGRect screenBounds = [[UIScreen mainScreen] bounds];
    if (screenBounds.size.height == 568)
    {
        // code for 4-inch screen
        iPhone5 = TRUE;
    }
    else
    {
        iPhone5 = FALSE;
        // code for 3.5-inch screen
    }
    return iPhone5;

}

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。

我发现答案并不包括模拟器的特殊情况。

#define IS_WIDESCREEN ( [ [ UIScreen mainScreen ] bounds ].size.height == 568  )
#define IS_IPHONE ([[ [ UIDevice currentDevice ] model ] rangeOfString:@"iPhone"].location != NSNotFound)
#define IS_IPAD ([[ [ UIDevice currentDevice ] model ] rangeOfString:@"iPad"].location != NSNotFound)
#define IS_IPHONE_5 ( IS_IPHONE && IS_WIDESCREEN )

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。