When using UISearchDisplayController with a UISearchBar in iPad it is displayed in a UIPopoverController. I would like to override the clear button as shown on the image to make
i did that once .. i replace the clear button with a custom button to make a custom action .. please check this
UISearchBar *searchBar = yourSearchController.searchBar;
UITextField *searchtextfield = [searchBar.subviews objectAtIndex:1];
UIButton *cButton = [UIButton buttonWithType:UIButtonTypeCustom];
cButton.frame = CGRectMake(0, 0, 20 , 20);
cButton.backgroundColor = [UIColor clearColor];
[cButton setImage:[UIImage newImageFromResource:@"yourButtonImage"] forState:UIControlStateNormal];//your button image.
cButton.contentMode = UIViewContentModeScaleToFill;
[cButton addTarget:self action:@selector(customButtonPressed) forControlEvents:UIControlEventTouchUpInside];//This is the custom event
[searchtextfield setRightView:cButton];
[searchtextfield setRightViewMode:UITextFieldViewModeAlways];
Good luck.