iOS app调用系统通讯录或者相册会出现导航条遮挡下面内容问题

1.在调用弹出之前加上以下代码：

if (@available(iOS 11.0, *)) {

        [[UIScrollView appearance] setContentInsetAdjustmentBehavior:UIScrollViewContentInsetAdjustmentAutomatic];

    }

2.在退出通讯录或相册时再设置还原

    if (@available(iOS 11.0, *)) {

        [[UIScrollView appearance] setContentInsetAdjustmentBehavior:UIScrollViewContentInsetAdjustmentNever];

    }