Question

我有UIViewController和UICollectionViewController。我使用以下内容将UICollectionViewController添加到UIViewController：

UICollectionViewFlowLayout* flowLayout = [[UICollectionViewFlowLayout alloc]init];
[flowLayout setScrollDirection:UICollectionViewScrollDirectionHorizontal];

self.toolsCollectionViewController = [[ToolsCollectionViewController alloc] initWithCollectionViewLayout:flowLayout];
self.toolsCollectionViewController.view.backgroundColor = [UIColor clearColor];

[self addChildViewController:self.toolsCollectionViewController];
[self.view addSubview:self.toolsCollectionViewController.view];
[self.toolsCollectionViewController didMoveToParentViewController:self];

问题在于，当我添加该集合时，我会看到一个黑色的纯黑屏幕，而且没有显示单元格

#import "ToolsCollectionViewController.h"

@interface ToolsCollectionViewController ()

@end

@implementation ToolsCollectionViewController

static NSString * const reuseIdentifier = @"Cell";

- (void)viewDidLoad {
    [super viewDidLoad];

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = NO;

    // Register cell classes
    [self.collectionView registerClass:[ToolsCollectionViewCell class] forCellWithReuseIdentifier:reuseIdentifier];

    // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

#pragma mark 

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
#warning Incomplete implementation, return the number of sections
    return 1;
}


- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
#warning Incomplete implementation, return the number of items
    return 10;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {

    ToolsCollectionViewCell *cell = (ToolsCollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];
    NSLog(@"Cell");
    // Configure the cell

    return cell;
}

#pragma mark 

/*
// Uncomment this method to specify if the specified item should be highlighted during tracking
- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath {
    return YES;
}
*/

/*
// Uncomment this method to specify if the specified item should be selected
- (BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    return YES;
}
*/

/*
// Uncomment these methods to specify if an action menu should be displayed for the specified item, and react to actions performed on the item
- (BOOL)collectionView:(UICollectionView *)collectionView shouldShowMenuForItemAtIndexPath:(NSIndexPath *)indexPath {
    return NO;
}

- (BOOL)collectionView:(UICollectionView *)collectionView canPerformAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(id)sender {
    return NO;
}

- (void)collectionView:(UICollectionView *)collectionView performAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(id)sender {

}
*/

@end

我为细胞循环创建了一个NSLog，这似乎工作正常。不确定我错过了什么。

Answer 1

您是否正确设置了collectionView的委托和dataSource？如果没有这两个，collectionView将显示为空，并且只显示一个用背景颜色着色的矩形。

您最需要的是将以下内容放在上面的- (void)viewDidLoad中： self.collectionView.delegate = self; self.collectionView.dataSource = self;

Answer 2

可能有3种不同的情景。

您实施的配色方案导致问题
没有正确调用Delegate和Datasource。
您的单元格不存在或重用标识符无效。

添加UICollectionViewController到UIViewController不工作

2 个答案: