Question

我创建了一个自定义UICollectionViewCell，你可以看到每个单元格的创建没有任何问题，可以找到xib，但屏幕上没有显示任何内容。

我已连接了ProgrammaCell的xib中委托的数据源。这是我的代码......

我的CollectionView被称为“griglia”，并在xib中连接

@interface GrigliaProgrammiViewController : UIViewController <UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout>
{    XMLParser *xmlParser;
}

....

@end

- (void)viewDidLoad
{
[super viewDidLoad];
   .....
[self.griglia registerClass:[ProgrammaCell class] forCellWithReuseIdentifier:@"prg"];
self.griglia.dataSource = self;
self.griglia.delegate = self;
xmlParser = [[XMLParser alloc]
loadXMLByURL:@"..."];
[self.griglia reloadInputViews];

}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:    (NSInteger)section {
return [[xmlParser programmi] count];}

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


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


ProgrammaCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"prg" forIndexPath:indexPath];
if (cell == nil) {
    NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"Programma" owner:self options:nil];
    cell = [nib objectAtIndex:0];
}

Programmi *programma = [[xmlParser programmi] objectAtIndex:indexPath.row];

cell.titolo.text= programma.titolo;
cell.giorno.text = programma.programma_giorno;
cell.orario.text = programma.programma_orario;


UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
activityIndicator.frame = cell.immagine.bounds;
[cell.immagine addSubview:activityIndicator];
[cell.immagine setImageWithURL:[NSURL URLWithString:programma.programma_copertina]
               placeholderImage:[UIImage imageNamed:@"placeholder.png"]
                      completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {
                      [activityIndicator removeFromSuperview];
                      }];
return cell;
}

Answer 1

您是如何初始化UICollectionView的？你使用什么类型的布局？我发现如果布局的itemsize太大，有时候不会调用cellForItemAtIndexPath。

请参阅问题UICollectionView's cellForItemAtIndexPath is not being called

Answer 2

您是否可以尝试在（void）viewDidLoad

中使用此代码段

NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"Programma" owner:self options:nil];
[self.griglia registerNib:nib forCellWithReuseIdentifier:@"prg"];

而不是原始代码：

[self.griglia registerClass:[ProgrammaCell class] forCellWithReuseIdentifier:@"prg"];

和

ProgrammaCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"prg" forIndexPath:indexPath];
//if (cell == nil) {
//    NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"Programma" owner:self options:nil];
//    cell = [nib objectAtIndex:0];
//}

我的猜测是registerClass：forCellWithReuseIdentifier：方法将您的类注册为可重用单元格，但您的单元类仅描述了单元格应该执行的操作（单元格的行为）。只有Nib文件描述了应该如何呈现单元格（单元格的UI）。

只是我的猜测，试一试。：）

Answer 3

来自笔尖的加载单元应该这样做：

[tableView registerNib:[UINib nibWithNibName:@"YourCellNibName" bundle:nil] forCellReuseIdentifier:JXVideoLikeMsgCellID];

不应从NSBundle加载

[[NSBundle mainBundle] loadNibNamed:@"YourCellNibName" owner:nil options:nil];

与UICollectionView相同。

UICollectionViewCell不显示单元格

3 个答案: