Create popup animation

How to create a pop up animation on iPhone? I want show my uivi开发者_开发问答ew as a popup view, like uialertview design.

- (void) killHUD
{

    [alertView dismissWithClickedButtonIndex:0 animated:YES];
    [alertView release];
    alertView = nil;
}
- (void)presentSheet:(NSString *)message withFrame:(CGRect)frame
{
    if(!alertView)
    {

        alertView = [[CustomAlertView alloc] initWithFrame:frame onView:self.window];
        alertView.autoresizingMask = UIViewAutoresizingFlexibleBottomMargin;
        [alertView setNeedsDisplay];
        [alertView setText:message];
        [alertView show];
    }
}

You can use these functions creaed by me to show an hide the loading animation popup..

Happy Coding..