UICollectionview为空

Question

您好我创建了一个UIViewController，因为我在CustomCell中添加了一个UICollectionView。然后，我为单元格创建了一个uicollectionviewcell类。最后在storybord本身设置委托和数据源。但它显示空页。如下图所示

CODE：

- (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

删除解决方案 [self.collectionview registerClass：[NewCell class] 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使得单元格的数量返回到0，因为数组尚未填充

试试这个

    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];

不需要此行

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

确保课程标题中有<UICollectioniewDatasource,UICollectionviewDelegate>

Answer 3

1. 在您的故事板中，为您的imageview tag例如{1}} 1，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viewController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];
   
       }
   

5. 集合视图中的项目数

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

         return [imageLabels count];
     }
     

6. 创建单元格并重复使用

   • (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;

}