Written by Der Teilweise
on August 06, 2012

UIAlertView+DHUserData

UserData for UIAlertView

Wouldn’t it be nice if one could add a custom object to every UIAlertView instance? With this tiny category, you can! Simply clone my repository at github.

Usage

Import the UIAlertView+DHUserData-Headerfile:

#import "UIAlertView+DHUserData.h"

In your code, simply use the dhUserData property to assign your custom data:

UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Customized"
                                                    message:@"This alert has custom data"
                                                   delegate:self
                                          cancelButtonTitle:@"Cancel"
                                          otherButtonTitles:@"Wow", @"Shocking" nil];
alertView.dhUserData = @{
   @"believable" : @NO,
   @"funfactor" : @"high"
};

In UIAlertView’s callback, your data is still there:

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
   NSLog(@"Believable: %@", [alertView.dhUserData objectForKey:@"believabe"]);
}

Implementation

UIAlertView+DHUserData uses associated data provided by the Objective-C runtime to store the user data. The getter/setter simply forward the calls to the matching Objective-C runtime calls:

- (void)setDhUserData:(id)dhUserData
{
    objc_setAssociatedObject(self,
                             DHUIAlertViewDHUserDataObjectKey,
                             dhUserData,
                             OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (id)dhUserData
{
    return objc_getAssociatedObject(self,
                                    DHUIAlertViewDHUserDataObjectKey);
}

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