请随意使用这个类(gist @ github)

代码已删除并重新定位到 https://gist.github.com/1323251

更新(01/14/11)

显然，这段代码现在有点过时了，但它肯定可以使用Brian Robbins提供的这个线程上的代码进行更新，其中包括更新模型的类似代码。谢谢你在这个帖子上的支持。

我知道答案已经被勾选了，但为了将来的参考，你可以总是使用设备屏幕大小来找出它是哪台设备:

if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {

    CGSize result = [[UIScreen mainScreen] bounds].size;

    if (result.height == 480) {
        // 3.5 inch display - iPhone 4S and below
        NSLog(@"Device is an iPhone 4S or below");
    }

    else if (result.height == 568) {
        // 4 inch display - iPhone 5
        NSLog(@"Device is an iPhone 5/S/C");
    }

    else if (result.height == 667) {
        // 4.7 inch display - iPhone 6
        NSLog(@"Device is an iPhone 6");
    }

    else if (result.height == 736) {
        // 5.5 inch display - iPhone 6 Plus
        NSLog(@"Device is an iPhone 6 Plus");
    }
} 

else if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
       // iPad 9.7 or 7.9 inch display.
       NSLog(@"Device is an iPad.");
}

你可以像这样使用UIDevice类:

NSString *deviceType = [UIDevice currentDevice].model;

if([deviceType isEqualToString:@"iPhone"])
    // it's an iPhone

我已经创建了一个扩展，让你有3个级别的识别:

设备类型 按英寸划分iPhone/iPad的类型 设备型号

它会随着最新的iOS设备进行更新

UIDeviceDetector

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];
}

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