NSTimer fire specific code, not selector

Question

I am trying to make a UIAlertView auto-dismiss after three seconds. I know how to make an NSTimer, and how to dismiss the UIAlertView separately, but I can't figure out how to make the dismiss-alert code run directly from the NSTimer, and NOT from a method.

Here is my code (the UIAlertView is named alert):

The timer:

[NSTimer scheduledTimerWithTimeInterval:3 target:self selector:@selector(method) userInfo:nil repeats:NO];

Dismiss the UIAlertView:

[alert dismissWithClickedButtonIndex:-1 animated:YES];

I can't dismiss the UIAlertView from a different method than the one that creates it (unless anyone knows of a way to that), so I need the above code to be called from within the first method, when the NSTimer fires.

Thanks in advance for any help / advice.

Answer 1

NSTimer only works with a selector, there is no way to directly call a method.

Use dispatch_after instead of a timer.

UIAlertView *alert = ... // create the alert view
[alert show];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
    [alert dismissWithClickedButtonIndex:alert.cancelButtonIndex animated:YES];
});

If you really want to use a timer you can do:

UIAlertView *alert = ... // create the alert view
[alert show];

[NSTimer scheduledTimerWithTimeInterval:3 target:self selector:@selector(dismissAlert:) userInfo:alert repeats:NO];

Then your timer method would be:

- (void)dismissAlert:(NSTimer *)timer {
    UIAlertView *alert = timer.userInfo;

    [alert dismissWithClickedButtonIndex:alert.cancelButtonIndex animated:YES];
}