自动布局= ViewWillAppear有错误的视图宽度。

I am using autolayout for parts of my UI. When I check the width of my view in viewWillAppear, the width has not yet updated. It gets updated after the second callback to - (void)updateViewConstraints. The issue is I set up my parts of my UI (using spring and struts for legacy reasons) based on this width in viewWillAppear. When is the good time to set up this legacy UI which takes in a width parameter ?I am using autolayout for parts of my UI. When