Question

我正在为UICollectionViewCell创建子类，并使用自动布局在代码中进行所有布局。这是我的init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.

当我不这样做时，我收到此错误： Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Auto Layout still required after executing -layoutSubviews. UICollectionView's implementation of -layoutSubviews needs to call super.' 如何让它显示我想要的方式？我错过了什么？

Answer 1

发表评论作为答案：

根据我的经验，collectionViewCells（和tableViewCells）需要他们的autoresizingmask或者他们抛出你看到的异常。但是由于您添加的子视图，您将遇到约束冲突，因此只需从其子视图中删除掩码：

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

我还试着记住在我使用alloc创建的视图上删除掩码（即不是从xib中删除），因为大多数时候它们会产生冲突。

自定义UICollectionViewCell自动布局NSInternalInconsistencyException错误

1 个答案: