UIAlertController custom font, size, color

Question

I am using new UIAlertController for showing alerts. I have this code:

// nil titles break alert interface on iOS 8.0, so we'll be using empty strings
UIAlertController *alert = [UIAlertController alertControllerWithTitle: title == nil ? @"": title message: message preferredStyle: UIAlertControllerStyleAlert];


UIAlertAction *defaultAction = [UIAlertAction actionWithTitle: cancelButtonTitle style: UIAlertActionStyleCancel handler: nil];

[alert addAction: defaultAction];

UIViewController *rootViewController = [UIApplication sharedApplication].keyWindow.rootViewController;
[rootViewController presentViewController:alert animated:YES completion:nil];

Now I want to change title and message font, color, size and so. What's best way to do this?

Edit: I should insert whole code. I created category for UIView that I could show right alert for iOS version.

@implementation UIView (AlertCompatibility)

+( void )showSimpleAlertWithTitle:( NSString * )title
                          message:( NSString * )message
                cancelButtonTitle:( NSString * )cancelButtonTitle
{
    float iOSVersion = [[UIDevice currentDevice].systemVersion floatValue];
    if (iOSVersion < 8.0f)
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle: title
                                                        message: message
                                                       delegate: nil
                                              cancelButtonTitle: cancelButtonTitle
                                              otherButtonTitles: nil];
        [alert show];
    }
    else
    {
        // nil titles break alert interface on iOS 8.0, so we'll be using empty strings
        UIAlertController *alert = [UIAlertController alertControllerWithTitle: title == nil ? @"": title
                                                                       message: message
                                                                preferredStyle: UIAlertControllerStyleAlert];


        UIAlertAction *defaultAction = [UIAlertAction actionWithTitle: cancelButtonTitle
                                                                style: UIAlertActionStyleCancel
                                                              handler: nil];

        [alert addAction: defaultAction];

        UIViewController *rootViewController = [UIApplication sharedApplication].keyWindow.rootViewController;
        [rootViewController presentViewController:alert animated:YES completion:nil];
    }
}

Answer 1

Not sure if this is against private APIs/properties but using KVC works for me on ios8

UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:@"Dont care what goes here, since we're about to change below" message:@"" preferredStyle:UIAlertControllerStyleActionSheet];
NSMutableAttributedString *hogan = [[NSMutableAttributedString alloc] initWithString:@"Presenting the great... Hulk Hogan!"];
[hogan addAttribute:NSFontAttributeName
              value:[UIFont systemFontOfSize:50.0]
              range:NSMakeRange(24, 11)];
[alertVC setValue:hogan forKey:@"attributedTitle"];



UIAlertAction *button = [UIAlertAction actionWithTitle:@"Label text" 
                                        style:UIAlertActionStyleDefault
                                        handler:^(UIAlertAction *action){
                                                    //add code to make something happen once tapped
}];
UIImage *accessoryImage = [UIImage imageNamed:@"someImage"];
[button setValue:accessoryImage forKey:@"image"];

For the record, it is possible to change alert action's font as well, using those private APIs. Again, it may get you app rejected, I have not yet tried to submit such code.

let alert = UIAlertController(title: nil, message: nil, preferredStyle: .ActionSheet)

let action = UIAlertAction(title: "Some title", style: .Default, handler: nil)
let attributedText = NSMutableAttributedString(string: "Some title")

let range = NSRange(location: 0, length: attributedText.length)
attributedText.addAttribute(NSKernAttributeName, value: 1.5, range: range)
attributedText.addAttribute(NSFontAttributeName, value: UIFont(name: "ProximaNova-Semibold", size: 20.0)!, range: range)

alert.addAction(action)

presentViewController(alert, animated: true, completion: nil)

// this has to be set after presenting the alert, otherwise the internal property __representer is nil
guard let label = action.valueForKey("__representer")?.valueForKey("label") as? UILabel else { return }
label.attributedText = attributedText

For Swift 4.2 in XCode 10 and up the last 2 lines are now:

guard let label = (action!.value(forKey: "__representer")as? NSObject)?.value(forKey: "label") as? UILabel else { return }
        label.attributedText = attributedText