从 UICollectionView 宽度设置 Ancor 约束中的宽度

Question

我需要使用 UICollectionView 的锚约束来构建 UIView。我插入的锚点都是正确的，但我的 widthAncor 有问题……我解释一下：

这是我的 CollectionView

_monthCollection = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:monthCollectionLayout];
    [self addSubview:_monthCollection];

    [_monthCollection.topAnchor constraintEqualToAnchor:self.topAnchor constant:65].active = YES;
    [_monthCollection.leftAnchor constraintEqualToAnchor:self.leftAnchor constant:2].active = YES;
    [_monthCollection.rightAnchor constraintEqualToAnchor:self.rightAnchor constant:0].active = YES;
    [_monthCollection.bottomAnchor constraintEqualToAnchor:self.bottomAnchor constant:0].active = YES;

这是我添加的 UIView

UIView *cursor = [[UIView alloc] init];
    cursor.backgroundColor = [UIColor colorWithHexString:@"#E66163" setAlpha:.4];
    cursor.layer.borderColor = [UIColor colorWithHexString:@"#E66163" setAlpha:1].CGColor;
    cursor.layer.borderWidth = 1;
    cursor.layer.cornerRadius = 15;
    cursor.translatesAutoresizingMaskIntoConstraints = NO;
    [_monthCollection addSubview:cursor];

    [cursor.topAnchor constraintEqualToAnchor:_monthCollection.topAnchor constant:0].active = YES;
    [cursor.leftAnchor constraintEqualToAnchor:_monthCollection.leftAnchor constant:0].active = YES;
    [cursor.widthAnchor constraintEqualToConstant:_monthCollection.frame.size.width].active = YES;
    [cursor.bottomAnchor constraintEqualToAnchor:_monthCollection.bottomAnchor constant:0].active = YES;

我需要 UIVIEW 的宽度等于 _monthCollection.frame.size.width / 3

我尝试了所有方法，但似乎约束我什么都不在乎..我无法得到任何结果...

所以我想知道......当我使用锚约束时如何插入我的宽度？

Answer 1

您使用了错误的方法来创建约束。您不想将其设置为常量，而是希望将视图的宽度限制为集合的宽度。我不会“说”ObjC，但我相信你可以轻松地将我的 Swift 代码重写为 objC：

cursor.widthAnchor.constraint(equalTo: _monthCollection.widthAnchor, multiplier: 0.33).isActive = true