UICollectionLayoutListConfiguration 可以支持页脚视图（如 tableFooterView 而不是部分页脚视图）吗？

Question

我正在使用 UICollectionLayoutListConfiguration 来制作像 UITableView 一样的 UICollectionView 布局。

但 UICollectionLayoutListConfiguration 中唯一支持的页脚视图模式似乎是 section 页脚视图。当该部分在屏幕上滚动时，它将固定到视图。

@property (nonatomic) UICollectionLayoutListFooterMode footerMode;
    
typedef NS_ENUM(NSInteger, UICollectionLayoutListFooterMode) {
        /// No footers are shown
        UICollectionLayoutListFooterModeNone,
        
        /// Uses supplementary views of kind UICollectionElementKindSectionFooter to show footers
        UICollectionLayoutListFooterModeSupplementary,
    } API_AVAILABLE(ios(14.0), tvos(14.0), watchos(7.0));

但我希望页脚视图的行为类似于 UITableView 的 tableFooterView ，它与任何部分无关，也不会固定屏幕。

如果我使用 UICollectionViewCompositionalLayoutConfiguration 而不是 UICollectionLayoutListConfiguration ，将会有一个 borderSupplementaryItems 属性来执行此操作。但 UICollectionLayoutListConfiguration 似乎对此没有边界SupplementaryItems。

有什么方法可以使用 UICollectionLayoutListConfiguration 制作 tableFooterView 布局吗？

Answer 1

我找到了一种方法来做到这一点：

使用sectionWithListConfiguration创建NSCollectionLayoutSection
现在您可以在该行部分使用boundarySuplementaryItems

演示代码已发布：

@interface ListFooterViewController:UIViewController
@end

@interface ListFooterViewController () <UICollectionViewDelegate, UICollectionViewDataSource>

@property (nonatomic, strong) UICollectionView *collectionView;

@end

@implementation ListFooterViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self setupCollectionView];
}

- (void)setupCollectionView {
    // 创建列表布局配置
    UICollectionLayoutListConfiguration *listConfig = [[UICollectionLayoutListConfiguration alloc] initWithAppearance:UICollectionLayoutListAppearancePlain];
    listConfig.footerMode = UICollectionLayoutListFooterModeSupplementary;

    // 创建并配置 UICollectionViewCompositionalLayout
    UICollectionViewCompositionalLayout *layout = [[UICollectionViewCompositionalLayout alloc] initWithSectionProvider:^NSCollectionLayoutSection * _Nullable(NSInteger section, id<NSCollectionLayoutEnvironment> _Nonnull layoutEnvironment) {
        // 创建列表布局
        NSCollectionLayoutSection *listSection = [NSCollectionLayoutSection sectionWithListConfiguration:listConfig layoutEnvironment:layoutEnvironment];
        
        // 添加页脚
        NSCollectionLayoutBoundarySupplementaryItem *footerItem = [NSCollectionLayoutBoundarySupplementaryItem boundarySupplementaryItemWithLayoutSize:[NSCollectionLayoutSize sizeWithWidthDimension:[NSCollectionLayoutDimension fractionalWidthDimension:1] heightDimension:[NSCollectionLayoutDimension absoluteDimension:50]] elementKind:UICollectionElementKindSectionFooter alignment:NSRectAlignmentBottom];
        listSection.boundarySupplementaryItems = @[footerItem];

        return listSection;
    }];

    // 创建并配置 UICollectionView
    self.collectionView = [[UICollectionView alloc] initWithFrame:self.view.bounds collectionViewLayout:layout];
    self.collectionView.backgroundColor = [UIColor systemBackgroundColor];
    self.collectionView.delegate = self;
    self.collectionView.dataSource = self;
    [self.view addSubview:self.collectionView];
    
    // 注册单元格和页脚视图
    [self.collectionView registerClass:[UICollectionViewListCell class] forCellWithReuseIdentifier:@"cell"];
    [self.collectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"footer"];
}

#pragma mark - UICollectionViewDataSource

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    return 1;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return 20;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
    cell.contentView.backgroundColor = [UIColor whiteColor];
    return cell;
}

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {
    UICollectionReusableView *footer = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"footer" forIndexPath:indexPath];
    footer.backgroundColor = [UIColor redColor];
    return footer;
}

#pragma mark - UICollectionViewDelegate

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"Selected item at indexPath: %@", indexPath);
}

@end

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    ListFooterViewController* vc = [ListFooterViewController new];
    [self.navigationController pushViewController:vc animated:YES];
}