ios - 自定义 UICollectionViewCell 自动布局 NSInternalInconsistencyException 错误

Question

我正在对 UICollectionViewCell 进行子类化，并使用自动布局在代码中完成所有布局。这是我的初始化方法:

- (id)initWithFrame:(CGRect)frame{
    frame = CGRectMake(0, 0, 403, 533);
    if (self = [super initWithFrame:frame]) {
        self.translatesAutoresizingMaskIntoConstraints = NO;

        PBCardPricesViewController *pricesView = [[PBCardPricesViewController alloc] init];
        [self addSubview:pricesView.view];

        UIImageView *background = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"CardBackground"]];
        [self addSubview:background];

        [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|-(20)-[background]|" options:0 metrics:nil views:@{@"background":background}]];
        [self addConstraint:[NSLayoutConstraint constraintWithItem:pricesView.view attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:background attribute:NSLayoutAttributeLeft multiplier:1 constant:0]];

        [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[background]|" options:0 metrics:nil views:@{@"background":background}]];
        [self addConstraint:[NSLayoutConstraint constraintWithItem:pricesView.view attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:background attribute:NSLayoutAttributeTop multiplier:1 constant:0]];
    }

    return self;
}

当我注释掉 translateAutoresizingMask 行时，我得到:

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:0x1d83f540 H:[UIImageView:0x1d83f950]-(0)-|   (Names: '|':PBCardViewCollectionCell:0x1d83b970 )>",

    "<NSAutoresizingMaskLayoutConstraint:0x1c55ad20 h=--& v=--& H:[PBCardViewCollectionCell:0x1d83b970(393)]>",

    "<NSAutoresizingMaskLayoutConstraint:0x1c559410 h=--& v=--& UIImageView:0x1d83f950.midX == + 191.5>",

    "<NSAutoresizingMaskLayoutConstraint:0x1c559450 h=--& v=--& H:[UIImageView:0x1d83f950(383)]>"

)



Will attempt to recover by breaking constraint 

<NSLayoutConstraint:0x1d83f540 H:[UIImageView:0x1d83f950]-(0)-|   (Names: '|':PBCardViewCollectionCell:0x1d83b970 )>



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.

如果我没有得到这个错误:由于未捕获的异常“NSInternalInconsistencyException”而终止应用程序，原因:“执行 -layoutSubviews 后仍需要自动布局。” UICollectionView 的 -layoutSubviews 实现需要调用 super.'我如何让它以我想要的方式显示？我错过了什么？

Answer 1

发表我的评论作为答案:

根据我的经验，collectionViewCells(和 tableViewCells)需要它们的 autoresizingmask 否则它们会抛出您看到的异常。但是由于您添加的 subview ，您会遇到约束冲突，因此只需从其 subview 中删除 mask 即可:

backgroundView.translatesAutoresizingMaskIntoConstraints = NO;  
pricesView.view.translatesAutoresizingMaskIntoConstraints = NO; // you might get it to work without doing this line

我也试着记住移除我使用 alloc 创建的 View 的掩码(即不是来自 xib)，因为大多数时候它们会产生冲突。