This presentation shows how to develop an universal iOS app or "convert" a existing one into universal. An universal app must work in iPad/iPod and iPhone.

1. Developing an
Universal iOS app
Or converting a existing one into universal...

2. –Apple Developer Documentation
“A universal app is a single app that is
optimized for iPhone, iPod touch, and iPad
devices.”

3. Universal app setup
• First you'll need to set project Devices as 'Universal'

4. –Morpheus
“You take the blue pill -- the story ends, you
wake up in your bed and believe whatever
you want to believe. You take the red pill --
you stay in Wonderland and I show you how
deep the rabbit-hole goes.”

5. ViewControllers
• Consider defining separate view controller
classes for iPhone and iPad devices.
• If you use a single view controller class for both
platforms, your code must support both iPhone
and iPad screen sizes.

6. Views
• Consider using separate sets of views for iPhone
and iPad devices. For custom views, this means
defining different versions of your class for each
device.
• If you choose to use the same custom view for
both devices, make sure your drawRect: and
layoutSubviews methods especially work
properly on both devices.

7. Using Runtime checks
if (UI_USER_INTERFACE_IDIOM() ==
UIUserInterfaceIdiomPad) {
// The device is an iPad running iOS 3.2
or later.
}
else {
// The device is an iPhone or iPod touch.
}

8. Drawing objects
self.wrapper.frame = CGRectMake(15,
10, self.frame.size.width - 30, 135);

9. Using different .XIB for the
same ViewController

10. if ([[UIDevice currentDevice] userInterfaceIdiom]
== UIUserInterfaceIdiomPhone) {
self = [super initWithNibName:nibNameOrNil
bundle:nibBundleOrNil];
} else {
self.view = [[[NSBundle mainBundle]
loadNibNamed:@"DDSigninFormViewController~ipad"
owner:self options:nil] objectAtIndex:0];
}

11. Live demo/coding

12. Thank you!
@wevtimoteo
weverton.ct@gmail.com