本文转载至 http://stackoverflow.com/questions/26460706/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];
    }
}

dupuis2387 · Accepted Answer · 2014-10-23 14:34:51Z

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"];

It's working. attributedTitle for title and attributedMessage for message. Not sure if it's best solution but for now it's good enough for me. – Libor Zapletal Oct 24 '14 at 9:18 — Libor Zapletal, Oct 24 '14 at 9:18

Oleg Gordiichuk · Answer 2 · 2014-10-20 09:02:20Z

This works fine and help to fix you're problem:

- (void)willPresentActionSheet:(UIActionSheet *)actionSheet {
 for (UIView *_currentView in actionSheet.subviews) {
        if ([_currentView isKindOfClass:[UILabel class]]) {
            UILabel *l = [[UILabel alloc] initWithFrame:_currentView.frame];
            l.text = [(UILabel *)_currentView text];
            [l setFont:[UIFont fontWithName:@"Arial-BoldMT" size:20]];
            l.textColor = [UIColor darkGrayColor];
            l.backgroundColor = [UIColor clearColor];
            [l sizeToFit];
            [l setCenter:CGPointMake(actionSheet.center.x, 25)];
            [l setFrame:CGRectIntegral(l.frame)];
            [actionSheet addSubview:l];
            _currentView.hidden = YES;
            break;
        }
    }
}

Also consider this tutorial about customization of the Alerts.

I get the idea that I should iterate through subviews. But - (void)willPresentActionSheet:(UIActionSheet *)actionSheet will not help me, will it? It uses UIActionSheetDelegate and UIAlertController not, right? – Libor Zapletal Oct 20 '14 at 8:01 — Libor Zapletal, Oct 20 '14 at 8:01
Implement UIActionSheetDelegate and than use this method to override parameters you want – Oleg Gordiichuk Oct 20 '14 at 8:05 — Oleg Gordiichuk, Oct 20 '14 at 8:05
But how can I set delegate on UIAlertController? – Libor Zapletal Oct 20 '14 at 8:57 — Libor Zapletal, Oct 20 '14 at 8:57
I edit my answer please take a look at tutorial it will help you – Oleg Gordiichuk Oct 20 '14 at 9:02 — Oleg Gordiichuk, Oct 20 '14 at 9:02
I guess I am stupid but I read the article but didn't find out anything about changing style for message and for title. – Libor Zapletal Oct 20 '14 at 11:25 — Libor Zapletal, Oct 20 '14 at 11:25

Ivan · Answer 3 · 2014-10-20 11:58:04Z

Use UIAppearance protocol. Example for setting a font - create a category to extend UILabel:

@interface UILabel (FontAppearance)
@property (nonatomic, copy) UIFont * appearanceFont UI_APPEARANCE_SELECTOR;
@end


@implementation UILabel (FontAppearance)

-(void)setAppearanceFont:(UIFont *)font {
    if (font)
        [self setFont:font];
}

-(UIFont *)appearanceFont {
    return self.font;
}

@end

And its usage:

UILabel * appearanceLabel = [UILabel appearanceWhenContainedIn:UIAlertController.class, nil];
[appearanceLabel setAppearanceFont:[UIFont boldSystemFontOfSize:10]]; //for example

Tested and working with style UIAlertControllerStyleActionSheet, but I guess it will work with UIAlertControllerStyleAlert too.

P.S. Better check for class availability instead of iOS version:

if ([UIAlertController class]) {
    // UIAlertController code (iOS 8)
} else {
    // UIAlertView code (pre iOS 8)
}

It's working but this way I can't have different size for message and for title. – Libor Zapletal Oct 20 '14 at 11:20 — Libor Zapletal, Oct 20 '14 at 11:20

score 0down vote · Answer 4

I know how to change button colour. but didn't know how to change font. you can change color of all button using below code.

alertC.view.tintColor = your color;

Maybe this will help you.

UIAlertController custom font, size, color

本文转载至 http://stackoverflow.com/questions/26460706/uialertcontroller-custom-font-size-color

4 Answers