iOS：UICollectionView实现的viewForSupplementaryElementOfKind轰炸

Question

我有这个方法为UICollectionView部分提供一个简单的哑页头：

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
    UICollectionReusableView *header = nil;

    NSString *sectionTitle;
    switch (indexPath.section) {
        case 0:
            sectionTitle = @"One";
            break;
        case 1:
            sectionTitle = @"Two";
            break;
        case 2:
            sectionTitle = @"Thre";
            break;
        case 3:
            sectionTitle = @"Four";
            break;
    }

    if (kind == UICollectionElementKindSectionHeader) {
        header = [collectionView dequeueReusableSupplementaryViewOfKind:kind
                                                    withReuseIdentifier:@"headerView"
                                                           forIndexPath:indexPath];

        UILabel *sectionLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
        sectionLabel.text = sectionTitle;
        [self.rosterCollectionView addSubview:sectionLabel];
    }


    return header;
}

它在dequeueReusableSupplementaryViewOfKind电话上炸弹：

*** Assertion failure in -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:], /SourceCache/UIKit/UIKit-2903.23/UICollectionView.m:3117

这里出了什么问题？

Answer 1

在使用dequeue方法之前，您应该使用registerNib:forSupplementaryViewOfKind:withReuseIdentifier:或registerClass:forSupplementaryViewOfKind:withReuseIdentifier:注册您的班级/笔尖