Declare an object of a class inside a condition - ios

Question

My requirement is that I want to declare an object of a class depending upon a condition that deviceFamily is iPad or iPhone.
I have developed an application for iPhone. Now I want to develop same application for iPad. Now I want to have two different .h , .m and .xib for iPhone and iPad with different names. But I want to use the same name object of two different classes in AppDelegate class of universal application.
Something like in .h file:
if(IS_iPad)
{
ViewController_iPad * obj;
}
else
{
ViewController_iPhone * obj;
}
So the I can use the same name of the object throughout the application.
How can I achieve this. Help!

Answer 1

This is probably the not best approach for creating a 'Universal' app (both iPad and iPhone) but for all of the instances I've seen adopting this model they seem to take the logic you have down a chain in regards to controllers...
UIViewController *sharedController = [[UIViewController alloc]init]; // things that are shared between both devices go in here (write once no duplication)
if([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) // PAD
{
ViewController_iPad * obj;
}
else if([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) // PHONE
{
ViewController_iPhone * obj;
}
Both of the view controller above should either include sharedController as a property to make use of the code in there OR better...
Make sharedController the 'base class'. Then make both ViewController_iPad and ViewController_iPhone sub classes of this class (shared).
To do this, in both ViewController_iPhone and ViewController_iPad's .h header files, set them as subclasses of sharedController like this.
#interface ViewController_iPad : sharedController
Its one approach if you really have to do it this way.

Answer 2

I would look into class clusters as explained at the iOS7 Tech Talks. Look at the end of the session "Architecting Modern Apps, Part 2", in the slides it starts at page 120.
Essentially, you can hide the exact implementation of a class from other classes that use it. In the image below, the app uses a class "Download Controller" but does not need to know if the OS is capable of NSURLSession or needs to default to NSURLConnection. I think this kind of pattern would work well with your problem.
The code for two such implementations would look something like this:
#interface MyViewController_iPhone : MyViewController #end
#interface MyViewController_iPad : MyViewController #end
#implementation MyViewController
+ (instancetype)newViewController {
if (IS_iPad) {
return [[MyViewController_iPad alloc] init];
} else {
return [[MyViewController_iPhone alloc] init];
}
}
...
#end

Answer 3

Maybe I understand now what you want to achieve: You want to define alternatively different objects, but access them outside the declaration scope by the same name. If so, what about:
#property (strong) UIViewController *obj;
...
if(IS_iPad)
{
obj = [[ViewController_iPad alloc] initWithNibName:nibName bundle:nil];
}
else
{
obj = [[ViewController_iPhone alloc] initWithNibName:nibName bundle:nil];
}
I assume both classes are subclasses of UIViewController, so the assignment would be OK. Of course one had to use the proper initialization for the view controllers.