ios为view添加一个圆角边框

 _monthBtnView.layer.cornerRadius = 2;

    _monthBtnView.layer.masksToBounds = YES;

    //给图层添加一个有色边框

    _monthBtnView.layer.borderWidth = 1;

    _monthBtnView.layer.borderColor = [[UIColor colorWithRed:199.0/255.0 green:199.0/255.0 blue:199.0/255.0 alpha:1] CGColor];