ios – 防止Interface Builder自动创建约束？

我创建了一个演示项目 here.我有一个视图,我在.xib文件中创建了一个ScrollView.在界面构建器中,我没有设置任何约束.在我的viewDidLoad方法中,我使用 SnapKit设置约束：

scrollView.snp_makeConstraints { (make) -> Void in
  make.edges.equalTo(self.view)
}

当我运行代码时,我得到以下控制台输出：

Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand,refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSIBPrototypingLayoutConstraint:0x7b74e280 'IB auto generated at build time for view with fixed frame' V:|-(1)-[UIScrollView:0x7b74c430]   (Names: '|':UIView:0x7b74dd10 )>","<<DeviceImagesTest.LayoutConstraint:0x7baa2760> <UIScrollView:0x7b6608d0>.top == <UIView:0x7b64d800>.top>"
)

Will attempt to recover by breaking constraint 
<NSIBPrototypingLayoutConstraint:0x7b74e280 'IB auto generated at build time for view with fixed frame' V:|-(1)-[UIScrollView:0x7b74c430]   (Names: '|':UIView:0x7b74dd10 )>

Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2015-05-29 18:37:14.368 DeviceImagesTest[36462:607] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand,refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSIBPrototypingLayoutConstraint:0x7b74e080 'IB auto generated at build time for view with fixed frame' H:|-(0)-[UIScrollView:0x7b74c430](LTR)   (Names: '|':UIView:0x7b74dd10 )>","<NSIBPrototypingLayoutConstraint:0x7b74e330 'IB auto generated at build time for view with fixed frame' H:[UIScrollView:0x7b74c430(600)]>","<<DeviceImagesTest.LayoutConstraint:0x7baa7170> <UIScrollView:0x7baa7b30>.right == <UIView:0x7baa79a0>.right>","<NSAutoresizingMaskLayoutConstraint:0x7baa4800 h=-&- v=-&- UIView:0x7b74dd10.width == UIViewControllerWrapperView:0x7ba9f060.width>","<NSAutoresizingMaskLayoutConstraint:0x7baa5180 h=-&- v=-&- UIViewControllerWrapperView:0x7ba9f060.width == UINavigationTransitionView:0x7bc769b0.width>","<NSAutoresizingMaskLayoutConstraint:0x7baa58e0 h=-&- v=-&- UINavigationTransitionView:0x7bc769b0.width == UILayoutContainerView:0x7bc75140.width>","<NSAutoresizingMaskLayoutConstraint:0x7baa61a0 h=-&- v=-&- UILayoutContainerView:0x7bc75140.width == UIWindow:0x7bc71870.width>","<NSAutoresizingMaskLayoutConstraint:0x7baa69a0 h=--- v=--- H:[UIWindow:0x7bc71870(320)]>"
)

Will attempt to recover by breaking constraint 
<<DeviceImagesTest.LayoutConstraint:0x7baa95b0> <UIScrollView:0x7baa9610>.right == <UIView:0x7baa96b0>.right>

Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2015-05-29 18:37:14.496 DeviceImagesTest[36462:607] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand,refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
    "<NSIBPrototypingLayoutConstraint:0x7b74e360 'IB auto generated at build time for view with fixed frame' V:[UIScrollView:0x7b74c430(600)]>","<<DeviceImagesTest.LayoutConstraint:0x7bc77e40> <UIScrollView:0x7bc7f6a0>.top == <UIView:0x7bc52180>.top>","<<DeviceImagesTest.LayoutConstraint:0x7bc49420> <UIScrollView:0x7bc74b00>.bottom == <UIView:0x7bc7b970>.bottom>","<NSAutoresizingMaskLayoutConstraint:0x7baa4960 h=-&- v=-&- UIView:0x7b74dd10.height == UIViewControllerWrapperView:0x7ba9f060.height>","<NSAutoresizingMaskLayoutConstraint:0x7baa51e0 h=-&- v=-&- UIViewControllerWrapperView:0x7ba9f060.height == UINavigationTransitionView:0x7bc769b0.height>","<NSAutoresizingMaskLayoutConstraint:0x7baa5940 h=-&- v=-&- UINavigationTransitionView:0x7bc769b0.height == UILayoutContainerView:0x7bc75140.height>","<NSAutoresizingMaskLayoutConstraint:0x7baa6200 h=-&- v=-&- UILayoutContainerView:0x7bc75140.height == UIWindow:0x7bc71870.height>","<NSAutoresizingMaskLayoutConstraint:0x7baa69d0 h=--- v=--- V:[UIWindow:0x7bc71870(568)]>"
)

Will attempt to recover by breaking constraint 
<<DeviceImagesTest.LayoutConstraint:0x7bc84790> <UIScrollView:0x7bc848b0>.bottom == <UIView:0x7bc84860>.bottom>

Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

看来Interface Builder正在为我生成约束,即使我没有设置任何约束.这导致与我在代码中设置的约束冲突.我还设置了setTranslatesAutoresizingMasks(false).

如何防止Interface Builder自动生成约束？

解决方法

如果您对该列表中的NSAutoresizingMaskLayoutConstraints感到困惑,可能是因为您没有在该视图上调用setTranslatesAutoresizingMasksIntoContraints(false). (虽然,我的印象是SnapKit会为你做这件事).

如果您对NSIBPrototypingLayoutConstraint感到困惑,那么Interface Builder会自动生成约束.要摆脱它,在Interface Builder中添加一些Top,Bottom,Leading和Trailing约束,并将它们设置为在构建时删除.有关详细信息,请查看http://travisjeffery.com/b/2013/11/preventing-ib-auto-generated-at-build-time-for-view-with-fixed-frame/

更新：网址已更改为http://travisjeffery.com/b/2013/11/preventing-ib-auto-generated-at-build-time-for-view-with-fixed-frame-when-using-auto-layout/