http://stackoverflow.com/questions/28642807/uisearchcontroller-change-cancel-button-title

swift version:

for view:UIView in (searchView?.subviews)!
{
for subView:UIView in (view.subviews)
{
if ( subView is UIButton )
{
let cancelBut = subView as! UIButton

            //do stuff with cancelButton here
        }
    }
}

You can change the "Cancel" Button in search bar using this-

for (UIView *view in searchBar.subviews)
{
for (id subview in view.subviews)
{
if ( [subview isKindOfClass:[UIButton class]] )
{
[subview setEnabled:YES];
UIButton cancelButton = (UIButton)subview;
[cancelButton setTitle:@"hi" forState:UIControlStateNormal];

        NSLog(@"enableCancelButton");
        return;
    }
}

}