ios - constraintsWithVisualFormat 可以与动态生成的 View 一起使用吗？

Question

我的模型中有一个标签列表。我想将它们作为标签添加到 tagView UIView 中作为 subview 。

NSMutableArray *list = [NSMutableArray new];
    for (long i=0; i<_tagView.subviews.count; i++) {
        UILabel *tagLabel = _tagView.subviews[i];
        [tagLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
        [list addObject:tagLabel];
    }

    // Create the views and metrics dictionaries
    NSDictionary *metrics = @{@"height":@25.0};
    NSDictionary *views = NSDictionaryOfVariableBindings(list[0], list[1], list[2]); 

// This is experimental as I assume there are three subviews in that.

    [_tagView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|-[list[0]]-[list[1]]-[list[2]]-|" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:metrics views:views]];

这是可行的还是我必须采取不同的方向？

我忘记添加我收到的错误消息:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unable to parse constraint format: 
list is not a key in the views dictionary. 
|-[list[0]]-[list[1]]-[list[2]]-| 
       ^'

更新:

键似乎没问题。

Answer 1

您应该创建自己的字典，这样就可以添加没有您现在得到的额外括号的名称。像“list[0]”这样的名称似乎会使解析器感到困惑。

 NSMutableDictionary *views = [NSMutableDictionary new];
 NSMutableArray *list = [NSMutableArray new];
        for (long i=0; i<_tagView.subviews.count; i++) {
            UILabel *tagLabel = _tagView.subviews[i];
            [tagLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
            [list addObject:tagLabel];
            [views setObject:tagLabel forKey:[NSString stringWithFormat:@"label%ld", i]];
        }

        NSDictionary *metrics = @{@"height":@25.0};

        [_tagView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|-[label1]-[label2]-[label3]-|" options:NSLayoutFormatAlignAllTop | NSLayoutFormatAlignAllBottom metrics:metrics views:views]];