iPhoneX

1.在有底部tab时，界面自动布局

[_subView mas_makeConstraints:^(MASConstraintMaker *make) {
            make.edges.equalTo(_subView.superview).with.insets(UIEdgeInsetsMake(0, 0, 0, 0));
        }];
        self.edgesForExtendedLayout = UIRectEdgeNone;//关键在于这一句