Usage of iOS Alert Dialogs

Alert dialogs are used to provide important information to the user.

Only after selecting an option in the alert dialog view can the user continue using the application.

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, as shown below, add <UIAlertViewDelegate> in ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UIAlertViewDelegate>{
    
}
@end

Add a 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 the delegate method of the alert dialog view

#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:

Other Extensions