UIActionSheet in iphone sdk

-(IBAction)btnChooseClicked:(id)sender{
    UIActionSheet *popupQuery = [[UIActionSheet alloc] initWithTitle:@"Title" delegate:self cancelButtonTitle:@"Cancel Button" destructiveButtonTitle:nil otherButtonTitles:@"Gallary", @"Camera", nil];
    popupQuery.actionSheetStyle = UIActionSheetStyleBlackOpaque;
    [popupQuery showInView:self.view];
    [popupQuery release];
}
-(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
    if (buttonIndex == 0) {
        if([UIImagePickerController isSourceTypeAvailable:
            UIImagePickerControllerSourceTypePhotoLibrary])
        {
            UIImagePickerController *picker= [[UIImagePickerController alloc]init];
            picker.delegate = self;
            picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
            [self presentModalViewController:picker animated:YES];
            [picker release];
        }
    }
    else if (buttonIndex == 1) {
       
    }
    else if (buttonIndex == 2) {
       
    }
    else if (buttonIndex == 3) {
       
    }
}