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

I have created very simple wrapper in Objective-C, that supports both - old iOS UIAlertView and new one UIAlertViewController

https://github.com/MartinPerry/UIAlert/

It also brings the new action blocks usage to old UIAlertView

Sample:

MyAlertMessage * a = [[MyAlertMessage alloc] initWithTitle:@"Hello" WithMessage:@"World"];

[a addButton:BUTTON_OK WithTitle:@"OK" WithAction:^(void *action) { 
  NSLog(@"Button OK at index 0 click"); 
}];

[a addButton:BUTTON_CANCEL WithTitle:@"Cancel" WithAction:^(void *action) {
  NSLog(@"Button Cancel at index 1 click"); 
}];

[a show];

Answer 2

Method one

by ios system version check

#define iOSVersionLessThan(v) ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)
// below ios8 ,create UIAlertView
if(iOSVersionLessThan(@"7.0")){
     // todo

// ios8 and above ,UIActionController avaliable
}else{
    // todo
}

Method two

by system feature detect

// create UIActionController 
if([UIActionController class]){
    // todo
// create UIAlertView
}else{
    // todo
}

But,there's a third lib named PSTAlertController that deal with backwards compatible to iOS 7 of UIActionSheet and UIAlertView.

ref to

• Supporting Multiple Versions of iOS
• Supporting iOS 6
• Supporting Multiple iOS Versions and Devices

Answer 3

As others have already mentioned - always check whether a feature exists. I believe the safest approach is following:

if (NSClassFromString(@"UIAlertController")) {
    // use UIAlertController
} else {
    // use UIAlertView
}

With the obvious risk of entering a class name with a typo. :)

From documentation of NClassFromString:

[Returns] The class object named by aClassName, or nil if no class by that name is currently loaded. If aClassName is nil, returns nil.

Availability iOS (2.0 and later)

Answer 4

// Above ios 8.0
float os_version = [[[UIDevice currentDevice] systemVersion] floatValue];
if (os_version >= 8.000000)
{
   　　　//Use UIAlertController    
}
else
{
     //UIAlertView
}

Answer 5

Please see the answer of Erwan (below my answer) as I see it is the best.

--

You can check the iOS version to use appropriate control like this:

if (([[[UIDevice currentDevice] systemVersion] compare:@"8.0" options:NSNumericSearch] == NSOrderedAscending)) {
    // use UIAlertView
}
else {
    // use UIAlertController
}