NSString *deviceType = [UIDevice currentDevice].model;

基于以上非常好的答案，以下是我想到的。这与@Rodrigo的回答非常相似，但解决了@Oliver对该回答的评论所关注的问题。这还提供了在输出字符串中包含模型字符串的选项。

+ (NSString *) deviceModel {
    size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *model = malloc(size);
    sysctlbyname("hw.machine", model, &size, NULL, 0);
    NSString *deviceModel = [NSString stringWithCString:model encoding:NSUTF8StringEncoding];
    free(model);      

    return deviceModel;
}

+ (NSString *) deviceName {
    NSString *deviceModel = [DeviceGateway deviceModel];                    

    if ([deviceModel isEqual:@"i386"])      return @"Simulator";  //iPhone Simulator
    if ([deviceModel isEqual:@"iPhone1,1"]) return @"iPhone1G";   //iPhone 1G
    if ([deviceModel isEqual:@"iPhone1,2"]) return @"iPhone3G";   //iPhone 3G
    if ([deviceModel isEqual:@"iPhone2,1"]) return @"iPhone3GS";  //iPhone 3GS
    if ([deviceModel isEqual:@"iPhone3,1"]) return @"iPhone4";    //iPhone 4 - AT&T
    if ([deviceModel isEqual:@"iPhone3,2"]) return @"iPhone4";    //iPhone 4 - Other carrier
    if ([deviceModel isEqual:@"iPhone3,3"]) return @"iPhone4";    //iPhone 4 - Other carrier
    if ([deviceModel isEqual:@"iPhone4,1"]) return @"iPhone4S";   //iPhone 4S
    if ([deviceModel isEqual:@"iPod1,1"])   return @"iPod1stGen"; //iPod Touch 1G
    if ([deviceModel isEqual:@"iPod2,1"])   return @"iPod2ndGen"; //iPod Touch 2G
    if ([deviceModel isEqual:@"iPod3,1"])   return @"iPod3rdGen"; //iPod Touch 3G
    if ([deviceModel isEqual:@"iPod4,1"])   return @"iPod4thGen"; //iPod Touch 4G
    if ([deviceModel isEqual:@"iPad1,1"])   return @"iPadWiFi";   //iPad Wifi
    if ([deviceModel isEqual:@"iPad1,2"])   return @"iPad3G";     //iPad 3G
    if ([deviceModel isEqual:@"iPad2,1"])   return @"iPad2";      //iPad 2 (WiFi)
    if ([deviceModel isEqual:@"iPad2,2"])   return @"iPad2";      //iPad 2 (GSM)
    if ([deviceModel isEqual:@"iPad2,3"])   return @"iPad2";      //iPad 2 (CDMA)

    NSString *aux = [[deviceModel componentsSeparatedByString:@","] objectAtIndex:0];

    //If a newer version exists
    if ([aux rangeOfString:@"iPhone"].location != NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPhone" withString:@""] intValue];
        if (version == 3) return @"iPhone4";
        if (version == 4) return @"iPhone4s";
        return @"Newer iPhone";
    }
    if ([aux rangeOfString:@"iPod"].location != NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPod" withString:@""] intValue];
        if (version == 4) return @"iPod4thGen";
        return @"Newer iPod";
    }
    if ([aux rangeOfString:@"iPad"].location != NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPad" withString:@""] intValue];
        if (version == 1) return @"iPad3G";
        if (version == 2) return @"iPad2";
        return @"Newer iPad";
    }

    //If none was found, send the original string
    return deviceModel;
}

+ (NSString *) deviceNameWithDeviceModel:(BOOL)shouldIncludeDeviceModel {
    if (shouldIncludeDeviceModel) {
        return [NSString stringWithFormat:@"%@ (%@)", [DeviceGateway deviceName], [DeviceGateway deviceModel]];
    }

    return [DeviceGateway deviceName];
}

这个代码怎么样，如果新版本发布，你将标识与最后知道的设备

- (NSString *)getModel {
    size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *model = malloc(size);
    sysctlbyname("hw.machine", model, &size, NULL, 0);
    NSString *sDeviceModel = [NSString stringWithCString:model encoding:NSUTF8StringEncoding];
    free(model);                              
    if ([sDeviceModel isEqual:@"i386"])      return @"Simulator";  //iPhone Simulator
    if ([sDeviceModel isEqual:@"iPhone1,1"]) return @"iPhone1G";   //iPhone 1G
    if ([sDeviceModel isEqual:@"iPhone1,2"]) return @"iPhone3G";   //iPhone 3G
    if ([sDeviceModel isEqual:@"iPhone2,1"]) return @"iPhone3GS";  //iPhone 3GS
    if ([sDeviceModel isEqual:@"iPhone3,1"]) return @"iPhone3GS";  //iPhone 4 - AT&T
    if ([sDeviceModel isEqual:@"iPhone3,2"]) return @"iPhone3GS";  //iPhone 4 - Other carrier
    if ([sDeviceModel isEqual:@"iPhone3,3"]) return @"iPhone4";    //iPhone 4 - Other carrier
    if ([sDeviceModel isEqual:@"iPhone4,1"]) return @"iPhone4S";   //iPhone 4S
    if ([sDeviceModel isEqual:@"iPod1,1"])   return @"iPod1stGen"; //iPod Touch 1G
    if ([sDeviceModel isEqual:@"iPod2,1"])   return @"iPod2ndGen"; //iPod Touch 2G
    if ([sDeviceModel isEqual:@"iPod3,1"])   return @"iPod3rdGen"; //iPod Touch 3G
    if ([sDeviceModel isEqual:@"iPod4,1"])   return @"iPod4thGen"; //iPod Touch 4G
    if ([sDeviceModel isEqual:@"iPad1,1"])   return @"iPadWiFi";   //iPad Wifi
    if ([sDeviceModel isEqual:@"iPad1,2"])   return @"iPad3G";     //iPad 3G
    if ([sDeviceModel isEqual:@"iPad2,1"])   return @"iPad2";      //iPad 2 (WiFi)
    if ([sDeviceModel isEqual:@"iPad2,2"])   return @"iPad2";      //iPad 2 (GSM)
    if ([sDeviceModel isEqual:@"iPad2,3"])   return @"iPad2";      //iPad 2 (CDMA)

    NSString *aux = [[sDeviceModel componentsSeparatedByString:@","] objectAtIndex:0];

//If a newer version exist
    if ([aux rangeOfString:@"iPhone"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPhone" withString:@""] intValue];
        if (version == 3) return @"iPhone4"
        if (version >= 4) return @"iPhone4s";

    }
    if ([aux rangeOfString:@"iPod"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPod" withString:@""] intValue];
        if (version >=4) return @"iPod4thGen";
    }
    if ([aux rangeOfString:@"iPad"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPad" withString:@""] intValue];
        if (version ==1) return @"iPad3G";
        if (version >=2) return @"iPad2";
    }
    //If none was found, send the original string
    return sDeviceModel;
}

为了简单的比较，我总是喜欢宏观:

#define IS_IPOD [[UIDevice currentDevice].model containsString:@"iPod"]
#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)

它简单易用。

下面提到的代码片段应该有帮助:

 if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
   // iPhone device
 }
 else if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
   // iPad device
 }
 else {
  // Other device i.e. iPod
 }

- (BOOL)deviceiPhoneOriPod
  {
    NSString *deviceType = [UIDevice currentDevice].model;
    if([deviceType rangeOfString:@"iPhone"].location!=NSNotFound)
      return YES;
    else
      return NO;
  }