Question

The code below is supposed to display the model/device name of the device running the app. For example, if the app was running on a 1st gen iPod, I want it to display “iPod1,1”. When I run the application, the label is empty. What am I doing wrong?

#import "ViewController.h"
#include <sys/types.h>
#include <sys/sysctl.h>

@interface ViewController ()

@end

@implementation ViewController
@synthesize label;

- (void)viewDidLoad
{
    label.text = [self platformString];
    [self platformCapabilities];

    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

- (NSString *) platform
{
size_t size;
sysctlbyname("hw.machine", NULL, &size, NULL, 0);
char *machine = malloc(size);
sysctlbyname("hw.machine", machine, &size, NULL, 0);
NSString *platform = [NSString stringWithCString:machine encoding: NSUTF8StringEncoding];
free(machine);
return platform;
}

- (int) platformType
{
NSString *platform = [self platform];
if ([platform isEqualToString:@"iPhone1,1"]) return UIDevice1GiPhone;
if ([platform isEqualToString:@"iPhone1,2"]) return UIDevice3GiPhone;
if ([platform isEqualToString:@"iPod1,1"])   return UIDevice1GiPod;
if ([platform isEqualToString:@"iPod2,1"])   return UIDevice2GiPod;
if ([platform hasPrefix:@"iPhone"]) return UIDeviceUnknowniPhone;
if ([platform hasPrefix:@"iPod"]) return UIDeviceUnknowniPod;
return UIDeviceUnknown;
}

- (NSString *) platformString
{
switch ([self platformType])
{
    case UIDevice1GiPhone: return IPHONE_1G_NAMESTRING;
    case UIDevice3GiPhone: return IPHONE_3G_NAMESTRING;
    case UIDeviceUnknowniPhone: return IPHONE_UNKNOWN_NAMESTRING;

    case UIDevice1GiPod: return IPOD_1G_NAMESTRING;
    case UIDevice2GiPod: return IPOD_2G_NAMESTRING;
    case UIDeviceUnknowniPod: return IPOD_UNKNOWN_NAMESTRING;

    default: return nil;
}
}

- (int) platformCapabilities
{
switch ([self platformType])
{
    case UIDevice1GiPhone: return UIDeviceBuiltInSpeaker | UIDeviceBuiltInCamera | UIDeviceBuiltInMicrophone | UIDeviceSupportsExternalMicrophone | UIDeviceSupportsTelephony | UIDeviceSupportsVibration;
    case UIDevice3GiPhone: return UIDeviceSupportsGPS | UIDeviceBuiltInSpeaker | UIDeviceBuiltInCamera | UIDeviceBuiltInMicrophone | UIDeviceSupportsExternalMicrophone | UIDeviceSupportsTelephony | UIDeviceSupportsVibration;
    case UIDeviceUnknowniPhone: return UIDeviceBuiltInSpeaker | UIDeviceBuiltInCamera | UIDeviceBuiltInMicrophone | UIDeviceSupportsExternalMicrophone | UIDeviceSupportsTelephony | UIDeviceSupportsVibration;

    case UIDevice1GiPod: return 0;
    case UIDevice2GiPod: return UIDeviceBuiltInSpeaker | UIDeviceBuiltInMicrophone | UIDeviceSupportsExternalMicrophone;
    case UIDeviceUnknowniPod: return 0;

    default: return 0;
}
}
@end

Also, how could I extend this code to recognize 3rd gen iPods, 4th gen iPods, etc?

Answer 1

You must be hitting your nil case. Did you try stepping into the platform method to see what it returns and if that matches any of your cases?