UISearchBar 设置背景色，去掉黑线

    self.searchBar = [[UISearchBar alloc]initWithFrame:CGRectMake(0, 5, self.view.bounds.size.width, 35)];

    self.searchBar.delegate = self;

    //设置背景色

    self.searchBar.barTintColor = [UIColor colorWithRed:239/255.0 green:240/255.0 blue:244/255.0 alpha:1.0];

    //设置右边的取消按钮

        for (id obj in [self.searchBar subviews]) {

            if ([obj isKindOfClass:[UIView class]]) {

                for (id obj2 in [obj subviews]) {

                    if ([obj2 isKindOfClass:[UIButton class]]) {

                        UIButton *btn = (UIButton *)obj2;

                        [btn setTitle:@"取消" forState:UIControlStateNormal];

                    }

                }

            }

        }

    [self.searchBar setBackgroundImage:[UIImage new]]; //去掉多余的黑线

    

    [self.view addSubview:self.searchBar];