使用3.5和4英寸外形尺寸的自动布局调整视图大小

我有一个原型tableview单元格，在tableview单元格的自定义视图。包含tableview的视图控制器将只以横向模式显示。目标是在tableview单元格内的UIView基于形状因子调整其宽度。因此，例如左右可能有20pt的间距，然后uiview调整其宽度以填充剩余的空间。我希望这样做与storyboard和autolayout。

I have a prototype tableview cell, with a custom view inside of the tableview cell. The view controller that contains the tableview will only be displayed in landscape mode. The goal is for the UIView that is inside of the tableview cell to resize it's width based on the form factor. So for example there might be a 20pt spacing on the left and right and then the uiview resizes it's width to fill the rest of the space. I'm hoping to do this with storyboard and autolayout.

在3.5英寸的外形中，它看起来像这样（这也是在4英寸模式下应该看起来像）

In 3.5 inch form factor it looks like this (this is what it should look like in 4 inch mode as well)

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4英寸形状因子看起来像这样（宽度没有自动调整大小）

In 4 inch form factor it looks like this (width didn't auto resize)

我知道这里的'auto layout'是合法的，因为水平空间在4英寸外形上大于20。问题的核心是...如何获得一个子视图自动调整宽度当屏幕的宽度改变使用storyboard / autolayout / constraints？

I understand that the 'auto layout' here is legal, since the horizontal space is >20 on the 4 inch form factor as well. The heart of the question though is... how do I get a subview to autoresize it's width when the width of the screen changes using storyboard/autolayout/constraints?