if(@available(iOS13, *)) {
// fix iOS13 tabbar 顶部有条线 line颜色和tabbar背景色相同
UIView *line = [[UIView alloc] initWithFrame:CGRectMake(0, -1, [UIScreen mainScreen].bounds.size.width, 1)];
line.backgroundColor = [UIColor whiteColor];
[_tabbar addSubview:line];
}
