设置UISearchBar的title和颜色

#pragma mark - UISearchBarDelegate
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar{
    searchBar.showsCancelButton = YES;
    for (UIView *view in self.searchController.searchBar.subviews[0].subviews) {
        if ([view isKindOfClass:[UIButton class]]) {
            UIButton *cancelBtn = (UIButton *)view;
            [cancelBtn setTitle:@"取消" forState:UIControlStateNormal];
            [cancelBtn setTitleColor:setRGBColor(41, 124, 240) forState:UIControlStateNormal];
            [cancelBtn setTitleColor:setRGBColor(41, 124, 240) forState:UIControlStateHighlighted];
        }
    }
}

或者使用KVC的方式：

    searchBar.showsCancelButton = YES;
    UIButton *cancelBtn = [searchBar valueForKey:@"_cancelButton"];
    [cancelBtn setTitle:@"取消" forState:UIControlStateNormal];
    [cancelBtn setTitleColor:setRGBColor(41, 124, 240) forState:UIControlStateNormal];
    [cancelBtn setTitleColor:setRGBColor(41, 124, 240) forState:UIControlStateHighlighted];

必须在UISearchBar代理方法中设置才生效，可能是因为此时searchBar的opaque属性才被设置为NO。