刚刚开始学习 iOS AutoLayout,界面构建器非常简单,但是当我尝试在代码上存档相同的内容时
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-(==2)-[_nextKeyboardButton]-(==2)-[_numPadButton]-(==2)-[_spaceButton]-(==2)-[_returnButton]-(==2)-|" options:0 metrics:0 views:NSDictionaryOfVariableBindings(_nextKeyboardButton,_numPadButton,_spaceButton,_returnButton)]];
它引发了一个异常,
无法同时满足约束条件。
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)
(
"<NSLayoutConstraint:0x6000000966c0 H:|-(2)-[UIButton:0x7fe4f1d1c760'Next'] (Names: '|':UIInputView:0x7fe4f1f04d00 )>",
"<NSLayoutConstraint:0x600000096710 H:[UIButton:0x7fe4f1d1c760'Next']-(2)-[UIButton:0x7fe4f1d1d1d0'123']>",
"<NSLayoutConstraint:0x600000096760 H:[UIButton:0x7fe4f1d1d1d0'123']-(2)-[UIButton:0x7fe4f1d1d6f0'Space']>",
"<NSLayoutConstraint:0x6000000967b0 H:[UIButton:0x7fe4f1d1d6f0'Space']-(2)-[UIButton:0x7fe4f1d1d8d0'Return']>",
"<NSLayoutConstraint:0x600000096800 H:[UIButton:0x7fe4f1d1d8d0'Return']-(2)-| (Names: '|':UIInputView:0x7fe4f1f04d00 )>",
"<NSLayoutConstraint:0x600000096e40 'UIView-Encapsulated-Layout-Width' H:[UIInputView:0x7fe4f1f04d00(0)]>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x6000000967b0 H:[UIButton:0x7fe4f1d1d6f0'Space']-(2)-[UIButton:0x7fe4f1d1d8d0'Return']>
所有 4 个按钮 .translatesAutoresizingMaskIntoConstraints = NO;
我想知道怎么了?非常感谢帮助:)
仅供参考:我从事 iOS8 SDK 工作
如何找到不可满足的约束的最简单方法:
- 创建简单的扩展
NSLayoutConstraint
:
SWIFT:
extension NSLayoutConstraint {
override public var description: String {
let id = identifier ?? ""
return "id: \(id), constant: \(constant)" //you may print whatever you want here
}
}
目标C
@interface NSLayoutConstraint (Description)
@end
@implementation NSLayoutConstraint (Description)
-(NSString *)description {
return [NSString stringWithFormat:@"id: %@, constant: %f", self.identifier, self.constant];
}
@end
如何简单地解决这种情况?
- 尝试改变priority to
999
对于打破的约束。
请参阅此处的相关答案:无法同时满足约束,将尝试通过打破约束来恢复 https://stackoverflow.com/a/30096600/2725435
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