UICollectionview 为空

Question

您好，我创建了一个UIViewController，其中我添加了一个带有CustomCell 的UICollectionView。然后，我为单元格创建了一个uicollectionviewcell 类。最后在 storybord 本身中设置委托和数据源。但它显示空白页面。如下图所示

代码：

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.collectionview = _collectionview;
    self.collectionview.dataSource = self;
    self.collectionview.delegate = self;

    speakersImages=[[NSMutableArray alloc]init];
    // Do any additional setup after loading the view, typically from a nib.
    imageLabels=[[NSMutableArray alloc]initWithObjects:@"RB Forum 2013",@"Agenda",@"Speakers",@"Contact",@"Map",@"Websites",@"@Responsible Biz",@"Partners",@"Sustainability",nil];


    imagePaths=[[NSMutableArray alloc]initWithObjects:[UIImage imageNamed:@"RBform.png"],[UIImage imageNamed:@"agenda.png"],[UIImage imageNamed:@"speakers.png"],[UIImage imageNamed:@"contact.png"],[UIImage imageNamed:@"map.png"],[UIImage imageNamed:@"website.png"],[UIImage imageNamed:@"twitter.png"],[UIImage imageNamed:@"partners.png"],[UIImage imageNamed:@"sustainability.png"], nil];
    [self.collectionview registerClass:[NewCell class] forCellWithReuseIdentifier:@"Cell"];



}

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

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

//THE BELOW DELEGATE METHOD DOES NOT GET CALLED!


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    // we're going to use a custom UICollectionViewCell, which will hold an image and its label
    //
    static NSString *CellIdentifier = @"Cell";
    NewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];

    // make the cell's title the actual NSIndexPath value

    cell.labels.text = [NSString stringWithFormat:@"%@",[imageLabels objectAtIndex:indexPath.row]];
    // load the image for this cell
    NSLog(@"%@",imageLabels);
    //NSString *imageToLoad = [NSString stringWithFormat:@"%d.JPG", indexPath.row];
    //    cell.image.image = [UIImage imageNamed:imageToLoad];
    cell.images.image = [imagePaths objectAtIndex:indexPath.row];

    return cell;

}

Answer 1

解决方案是删除 [self.collectionview registerClass:[NewCell 类] forCellWithReuseIdentifier:@"Cell"];

在storybord中我们不需要这个

Answer 2

代码没问题，但顺序不同。在填充数组之前分配数据源和委托会使单元格的数量返回为 0，因为尚未填充数组

这样试试

    speakersImages=[[NSMutableArray alloc]init];
    // Do any additional setup after loading the view, typically from a nib.
    imageLabels=[[NSMutableArray alloc]initWithObjects:@"RB Forum 2013",@"Agenda",@"Speakers",@"Contact",@"Map",@"Websites",@"@Responsible Biz",@"Partners",@"Sustainability",nil];


    imagePaths=[[NSMutableArray alloc]initWithObjects:[UIImage imageNamed:@"RBform.png"],[UIImage imageNamed:@"agenda.png"],[UIImage imageNamed:@"speakers.png"],[UIImage imageNamed:@"contact.png"],[UIImage imageNamed:@"map.png"],[UIImage imageNamed:@"website.png"],[UIImage imageNamed:@"twitter.png"],[UIImage imageNamed:@"partners.png"],[UIImage imageNamed:@"sustainability.png"], nil];
    [self.collectionview registerClass:[NewCell class] forCellWithReuseIdentifier:@"Cell"];
   [self.collectionview reloadData];

这行不需要

self.collectionview = _collectionview;
self.collectionview.dataSource = self;
    self.collectionview.delegate = self;

还要确保您的收藏视图通过插座连接

确保<UICollectioniewDatasource,UICollectionviewDelegate> 在类头中

Answer 3

1. 在你的故事板中给你的imageview 一个tag 例如1，以及您的label 另一个tag，例如2

2. 提供您已经提供的 cell 重用标识符，例如。 "Cell"

3. 现在在您的故事板中右键单击collection view 并为您的视图控制器或文件所有者创建datasource 和delegate。或者，您可以在 viewController 中使用 <UICollectionViewDataSource,UICollectionViewDelegate> 并将委托和数据源设置为 self。

4. 现在在你的 viewDidLoad 中

-(void)viewDidLoad{

            self.collectionview.dataSource = self;
            self.collectionview.delegate = self;
        
            speakersImages=[[NSMutableArray alloc]init];
            // Do any additional setup after loading the view, typically from a nib.
            imageLabels=[[NSMutableArray alloc]initWithObjects:@"RB Forum   2013",@"Agenda",@"Speakers",@"Contact",@"Map",@"Websites",@"@Responsible     Biz",@"Partners",@"Sustainability",nil];
        
        
            imagePaths=[[NSMutableArray alloc]initWithObjects:[UIImage imageNamed:@"RBform.png"],[UIImage imageNamed:@"agenda.png"],[UIImage imageNamed:@"speakers.png"],[UIImage imageNamed:@"contact.png"],[UIImage imageNamed:@"map.png"],[UIImage imageNamed:@"website.png"],[UIImage imageNamed:@"twitter.png"],[UIImage imageNamed:@"partners.png"],[UIImage imageNamed:@"sustainability.png"], nil];
        
        }

6. 集合视图中的项目数

   • (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection：（NSInteger）部分 {

           return [imageLabels count];
       }
     

7. 创建单元并重用

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

                   UICollectionView *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell"];
     
                   // make the cell's title the actual NSIndexPath value
     
                   UIlabel *label = (UIlabel *) [cell viewWithTag:2]
                   label.text = [NSString stringWithFormat:@"%@",[imageLabels   objectAtIndex:indexPath.row]];
     
                   // load the image for this cell
                   UIImageView *imageView = (UIImageView *) [cell viewWithTag:1]
                   imageView.image = [imagePaths objectAtIndex:indexPath.row];
     
                   return cell;
     
               }
     

Answer 4

- (void)viewDidLoad
{
    [super viewDidLoad];

 [self.collectionView registerNib:[UINib nibWithNibName:@"NewCell" bundle:nil] forCellWithReuseIdentifier:@"CELL"];

    self.collectionview.dataSource = self;
    self.collectionview.delegate = self;


self.imageLabels = [NSArray arrayWithObjects:@"RB Forum 2013",@"Agenda",@"Speakers",@"Contact",@"Map",@"Websites",@"@Responsible Biz",@"Partners",@"Sustainability",nil];

self.imagePaths=[NSArray arrayWithObjects::@"RBform.png",@"agenda.png",@"speakers.png",@"contact.png",@"map.png",@"website.png",@"twitter.png",@"partners.png",@"sustainability.png", nil];



}

- (NSInteger)collectionView:(UICollectionView *)collectionView
     numberOfItemsInSection:(NSInteger)section
{
    return [self.imageLabels count];
}

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

    NewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CELL" forIndexPath:indexPath];

    cell.labels.text = [self.imageLabels objectAtIndex:indexPath.row]];
    cell.images.image = [UIImage imageNamed:[self.imagePaths objectAtIndex:index path.row]];

    return cell;

}