The document discusses the process of developing a universal iOS app that works on iPhone, iPod touch, and iPad devices, emphasizing the need for proper project setup and view controller management. It suggests defining separate view controllers and views for different devices while ensuring that shared classes support both platforms. Additionally, it outlines the use of runtime checks and different .xib files for effective optimization of the app across devices.

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