ios - 防止 Interface Builder 自动创建约束？

Question

我创建了一个演示项目 here .我有一个 View ，我在 .xib 文件中创建了一个 ScrollView。在界面生成器中，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.

似乎 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发生冲突。我还设置了 setTranslatesAutoresizingMasks(false)。

如何防止 Interface Builder 自动生成约束？

Answer 1

如果您对该列表中的 NSAutoresizingMaskLayoutConstraints 感到困惑，可能是因为您尚未对该 View 调用 setTranslatesAutoresizingMasksIntoContraints(false)。 (不过，我的印象是 SnapKit 会为您做到这一点)。

如果您对 NSIBPrototypingLayoutConstraint 感到困惑，那是 Interface Builder 自动生成的约束。要摆脱它，请在 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。有关更多详细信息，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/