Short answer: Yes.
Provided you follow the model/view/controller style, you can re-use the same View and Viewcontroller (.h and .m) files in both an iPad nib and an iPhone nib (or storyboard). There will be occasions when you need to use the following type of code, though:
BOOL iPad = (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad);
if (iPad) {
.... iPad specific code like SplitViewController
} else {
.... iPhone / iPod Touch specific code
}
You may also need to check if the view controller you are in is on-screen (as on the iPad more than one ViewController can be onscreen), in which case use:
if (self.view.window) {
.... ViewController onscreen so do something otherwise do nothing
}
Also don't hardcode the bounds of the device's screen. Use the following to find your screen size (in points):
CGRect screenBounds = [[UIScreen mainScreen] bounds];
Hope this helps.