ios11:自定义tabbar图标出现重影

解决方法：在自定义tabbar这个类的-(void)viewWillAppear:(BOOL)animated；

-(void)viewWillAppear:(BOOL)animated

{

    [super viewWillAppear:animated];

    for(UIView* view in self.tabBar.subviews)

        {

                if(![viewisKindOfClass:[TabBar class]]) {

                [viewremoveFromSuperview];

                }

        }

}

可能不会成功，在主要的视图layoutSubView中再删除一次,以防出现的时候不能删除,在viewWillAppear中删除只是保证删除一次

所以要进行多次删除

-(void)viewWillLayoutSubviews

{

    [super viewWillLayoutSubviews];

    for(UIView * viewin self.tabBar.subviews)

    {

        if(![view isKindOfClass:[TabBar class]]) {

            [view removeFromSuperview];

        }

    }

}