UISearchBar customize Keyboard Return button type (iOS 7)

gistfile1.m

for (UIView *subview in searchBar.subviews) {
    for (UIView *subSubview in subview.subviews) {
        if ([subSubview conformsToProtocol:@protocol(UITextInputTraits)]) {
            UIView<UITextInputTraits> *textInputField = (UIView<UITextInputTraits> *)subSubview;
            textInputField.returnKeyType = UIReturnKeyDone;
            break;
        }
    }
}