Usage of iOS Alert Dialogs

Alert dialogs are used to provide important information to users.

Further use of the application can only be initiated after selecting an option in the alert dialog view.

Important Properties

• alertViewStyle
• cancelButtonIndex
• delegate
• message
• numberOfButtons
• title

Important Methods

- (NSInteger)addButtonWithTitle:(NSString *)title

- (NSString *)buttonTitleAtIndex:(NSInteger)buttonIndex

- (void)dismissWithClickedButtonIndex:(NSInteger)buttonIndex animated:(BOOL)animated

- (id)initWithTitle:(NSString *)title message:(NSString *)message delegate:(id)delegate cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSString *)otherButtonTitles, ...

- (void)show

Update ViewController.h as follows

Make the class conform to the alert dialog view's delegate protocol by adding <UIAlertViewDelegate> in ViewController.h.

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UIAlertViewDelegate> {

}
@end

Add Custom Method addAlertView

-(void)addAlertView {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Title" message:@"This is a test alert" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Ok", nil];
    [alertView show];
}

Implement Alert Dialog View's Delegate Methods

#pragma mark - Alert view delegate
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
    switch (buttonIndex) {
        case 0:
            NSLog(@"Cancel button clicked");
            break;
        case 1:
            NSLog(@"OK button clicked");
            break;

        default:
            break;
    }
}

Modify viewDidLoad in ViewController.m as follows

(void)viewDidLoad {
   [super viewDidLoad];
   [self addAlertView];
}

Output

Now when we run the application, we will see the following output: