Why do my UIAlertActions become nil on iPad Air - ios

Question

I'm working on an old iOS app originally written for iOS 6, and it had some UIActionSheets that needed to be changed, so I've been working to move them over to UIAlertControllers, using UIAlertActions. This has worked perfectly fine on a iPad2 Simulator, however when testing on an iPad Air (the only iPad I have access to) my UIAlertAction, and UIAlertController become nil directly after being created (looked at in the debugger, it receives a pointer on creation, however as soon as it executes the next line it becomes null). Here's a code sample:
//When hovering over the next line, alert has a pointer
UIAlertController* alert = [UIAlertController
alertControllerWithTitle:#"info"
message:#"testmessage"
preferredStyle:UIAlertControllerStyleActionSheet];
//alert pointer is now nil
//test pointer shows up
UIAlertAction* test= [UIAlertAction
actionWithTitle:#"I'm a Button"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action){
[alert dismissViewControllerAnimated: YES completion:nil];
}
];
//test pointer is nil, test2 pointer exists
UIAlertAction* test2 = [UIAlertAction
actionWithTitle:#"I'm a Button"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action){
[alert dismissViewControllerAnimated: YES completion:nil];
}
];
//test2 pointer is nil
[alert addAction:test];
[self presentViewController:alert animated:YES completion:nil]; //app crashes, because I'm trying to present a nil modal.
Any thoughts or help would be much appreaciated!

Answer 1

UIAlertController is for iOS8 upwards. Use UIAlertView and UIActionSheet for prior to iOS8
You are best to check wether your device responds to the class,
if ([UIAlertController class]) {
// use UIAlertController for the action sheets as you have already posted
// For all operating systems (like iOS8 upwards) will land in here.
} else {
// use UIActionSheet - like you already used for iOS6
}
It's not wise to check the operating system deployment number, like if 8.0 etc, checking the if it responds to the class is the proper way to do it.
It prevents a crash means you're not relying on float numbers which are not guaranteed to be reliable, as if they change the way the operating systems is named in future, your code would crash.