Deactive NSLayoutConstraint iOS7 [英] Deactive NSLayoutConstraint iOS7

问题描述

我正在开发一款目标为iOS7的应用，当我将应用部署到iPhone 4时出现以下错误。

I'm developing an app with a target of iOS7, and I get the following error when I deploy the app to an iPhone 4.

[NSLayoutConstraint setActive:]: unrecognized selector sent to instance

我调查了这个和事实证明，iOS8中引入了 setActive 。问题是，对于约束，大约iOS7， setActive 的替代方法是什么？我需要以编程方式操作约束，似乎无法在任何地方找到答案。

I looked into this and it turns out that setActive was introduced in iOS8. Question is, what is the alternative to setActive for constraints, circa iOS7? I need to manipulate the constraints programmatically and can't seem to find the answer anywhere.

推荐答案

另一种方法是从视图中添加/删除约束：

Another way to do this would be to add/remove the constraint from the view:

[myView addConstraint：constraint];

[myView removeConstraint：constraint];

这是自从iOS 6.0。 https：// developer .apple.com / library / ios / documentation / UIKit / Reference / UIView_Class / index.html＃// apple_ref / occ / instm / UIView / addConstraint：

This has been available since iOS 6.0. https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/index.html#//apple_ref/occ/instm/UIView/addConstraint:

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