UIAlertController if iOS 8, otherwise UIAlertView

Question

I want to conform to the UIAlertController used in iOS 8 since UIAlertView is now deprecated. Is there a way that I can use this without breaking support for iOS 7? Is there some kind of if condition I can do to check for iOS 8 otherwise do something else for iOS 7 support?

Answer 1

Create simple utility function to reduce code

CODE :

// pass minimum required iOS version
BOOL isOSSupported(NSString *minRequiredVersion)
{
    NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
    BOOL isOSSupported = ([currSysVer compare:minRequiredVersion options:NSNumericSearch] != NSOrderedAscending) && 
                                  ![currSysVer isEqualToString:@"Unknown"];
    return isOSSupported;
}

USE :

if(isOSSupported("8.0")
{
// Code for iOS8 and above
}
else
{
// Code for iOS7 and below
}

---

Or Use system constant NSFoundationVersionNumber_iOS_7_1 as below

if(floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_7_1)
{
   // Code for iOS8 and above
}
else
{
   // Code for iOS7 and below
}

for more options Link

Answer 2

Objective C (as mentioned above)

if ([UIAlertController class]) {
    // use UIAlertController

} else {
    // use UIAlertView

}

Swift

if objc_getClass("UIAlertController") == nil  {
       // use UIAlertView 

} else {
  // use UIAlertController

}

Don't use if NSClassFromString("UIAlertController") == nil It is not working because the signature for this method is func NSClassFromString(_ aClassName: String!) -> AnyClass!

Answer 3

I think a much better way to check if a class exists (since iOS 4.2) is:

if([ClassToBeChecked class]) {

   // use it

} else {

  // use alternative

}

In your case, that would be:

if ([UIAlertController class]) {
   // use UIAlertController

} else {
  // use UIAlertView

}

Answer 4

I have written one class that wrap the UIAlertView and use UIAlertController. For the programmer is transparently hence is sufficient import this classes in the project. The utility of this classes is when in a old project there are more UIAlertView to change. Link: https://github.com/kennymuse/UIAlertView

Answer 5

Try below code. It works fine for both iOS 8 and below version.

if (IS_OS_8_OR_LATER) {
UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:title message:msg preferredStyle:UIAlertControllerStyleAlert];

UIAlertAction *cancelAction = [UIAlertAction
                             actionWithTitle:@"OK"
                             style:UIAlertActionStyleCancel
                             handler:^(UIAlertAction *action)
                             {

                             }];
[alertVC addAction:cancelAction];

[[[[[UIApplication sharedApplication] windows] objectAtIndex:0] rootViewController] presentViewController:alertVC animated:YES completion:^{

}];
}
else{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title message:msg delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
    [alert show];
}

Answer 6

Solution for checking iOS version in Swift

switch (UIDevice.currentDevice().systemVersion.compare("8.0.0", options: NSStringCompareOptions.NumericSearch)) {
    case .OrderedAscending:
       println("iOS < 8.0")

    case .OrderedSame, .OrderedDescending:
       println("iOS >= 8.0")
}

Con of this solution: it is simply bad practice to check against OS version numbers, whichever way you do it. One should never hard code dependencies in this way, always check for features, capabilities or the existence of a class. Consider this; Apple may release a backwards compatible version of a class, if they did then the code you suggest would never use it as your logic looks for an OS version number and NOT the existence of the class.

(Source of this information)

Solution for checking the class' existence in Swift

if (objc_getClass("UIAlertController") == nil) {
   // iOS 7
} else {
   // iOS 8+
}

Do not use if (NSClassFromString("UIAlertController") == nil) because it works correctly on the iOS simulator using iOS 7.1 and 8.2, but if you test on a real device using iOS 7.1, you will unfortunately notice that you will never pass through the else part of the code snippet.