将 UILabel 固定到 UICollectionViewCell contentView 按钮的自动布局约束
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【中文标题】将 UILabel 固定到 UICollectionViewCell contentView 按钮的自动布局约束【英文标题】:Autolayout Constraint to Pin UILabel to button of UICollectionViewCell contentView 【发布时间】:2013-06-26 18:47:39 【问题描述】:我正在尝试使用可视化格式化语言向 UICollectionViewCell 子类添加一个简单的约束。我只想将 UILabel 固定到 contentView 的底部。这是我的初始化代码:
- (id)initWithFrame:(CGRect)frame
self = [super initWithFrame:frame];
if(self)
_label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 128, 50)];
_label.font = [[UIFont preferredFontForTextStyle:UIFontTextStyleSubheadline1] fontWithSize:20.0];
_label.lineBreakMode = NSLineBreakByWordWrapping;
_label.numberOfLines = 2;
_label.contentMode = UIViewContentModeBottom;
_label.backgroundColor = [UIColor blackColor];
[self.contentView addSubview:_label];
[self.contentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[_label]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_label)]];
return self;
这是我在运行应用程序时收到的示例日志消息。
Unable to simultaneously satisfy constraints.
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)
(
"<NSLayoutConstraint:0xa3aa620 V:[UILabel:0xa3aa270]-(0)-| (Names: '|':UIView:0xa3aa010 )>",
"<NSAutoresizingMaskLayoutConstraint:0x8b9b2d0 h=--& v=--& UILabel:0xa3aa270.midY == + 25>",
"<NSAutoresizingMaskLayoutConstraint:0x8b9bba0 h=--& v=--& V:[UILabel:0xa3aa270(50)]>",
"<NSAutoresizingMaskLayoutConstraint:0x8bd1290 h=-&- v=-&- UIView:0xa3aa010.height == STStationGroupCollectionViewCell:0xa3a9f40.height>",
"<NSAutoresizingMaskLayoutConstraint:0x8bb7ee0 h=--& v=--& V:[STStationGroupCollectionViewCell:0xa3a9f40(128)]>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0xa3aa620 V:[UILabel:0xa3aa270]-(0)-| (Names: '|':UIView:0xa3aa010 )>
非常感谢任何帮助。谢谢!
【问题讨论】:
【参考方案1】:尝试添加:
_label.translatesAutoresizingMaskIntoConstraints = NO;
似乎有一个自动调整大小约束试图修复标签的 midY。
【讨论】:
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