API to determine whether running on iPhone or iPad [duplicate]

Is there an API for checking at runtime whether you are running on an iPhone or an iPad?

One way I can think of would be to use:

[[UIDevice currentDevice] model];

And detect the existence of the string @"iPad" - which seems a bit fragile.

In the 3.2 SDK, I see that UIDevice also has a property which is really what I'm looking for, but doesn't work for pre-3.2 (obviously):

[[UIDevice currentDevice] userInterfaceIdiom]; 

Are there other ways than checking for the existence of @"iPad" for a universal app?

Checkout UI_USER_INTERFACE_IDIOM.

Returns the interface idiom supported by the current device.

Return Value
UIUserInterfaceIdiomPhone if the device is an iPhone or iPod touch or UIUserInterfaceIdiomPad if the device is an iPad.

UIUserInterfaceIdiom

The type of interface that should be used on the current device

typedef enum {
   UIUserInterfaceIdiomPhone,
   UIUserInterfaceIdiomPad,
} UIUserInterfaceIdiom;

Just for my reference:

@property (nonatomic, readonly) BOOL isPhone;

-(BOOL)isPhone {
    return (UI_USER_INTERFACE_IDIOM()==UIUserInterfaceIdiomPhone);
}

or use a #define

#define IS_PHONE  (UI_USER_INTERFACE_IDIOM()==UIUserInterfaceIdiomPhone)

However, if you're using isPhone all over your code, that's generally bad practice. Use the factory pattern and polymorphism to keep your if statements contained, so you get objects created for phone or for iPad and then work with those.

Added

I'm using this solution all over my code now. It adds a standard factory pattern into the alloc.

#define ALLOC_PER_DEVICE()  id retVal = nil; \
                        NSString *className = NSStringFromClass(self);\
                        if (IS_PHONE && ![className hasSuffix:@"Phone"]) {\
                            className = [NSString stringWithFormat:@"%@Phone", className];\
                            Class newClass = NSClassFromString(className);\
                            retVal = [newClass alloc];\
                        }\
                        if (!retVal)\
                            retVal = [super alloc];\
                        assert(retVal != nil);\
                        return retVal\

Then my allocs look like this:

+alloc { ALLOC_PER_DEVICE(); }

And I add a subclass called TheClassPhone for the phone version.

Note: Since there's no multiple inheritance in Objective-C, using inheritance to solve your problems is a bit overrated (i.e., it doesn't work if you have subclasses of subclasses). Nothing like a good if when you need it.

Use NSClassFromString and an iPad-specific class. Read more here:

http://developer.apple.com/iphone/library/documentation/General/Conceptual/iPadProgrammingGuide/StartingYourProject/StartingYourProject.html#//apple_ref/doc/uid/TP40009370-CH9-SW3

1. Check for the presence of the userInterfaceIdiom property, usings respondsToSelector:. If it doesn't exist, we are on a pre-3.2 device, thus not an iPad.
2. If userInterfaceIdiom exists, use it.

Edit: ... which is obviously exactly what the UI_USER_INTERFACE_IDIOM() macro does, so use that instead. :)