UICollectionView单元格显示不正确

Question

在我的CollectionView中，它是水平的，不能正确显示视图。为什么呢？

在下面显示的图片中，粉红色是CollectionView，橙色是为什么细胞显示奇怪的细胞。对于单元1，存在右侧空间，对于单元2，存在左侧空间，对于单元3，尺寸在左侧稍微增加。为什么这种奇怪的行为？

这是我的代码：

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
        return 3;
}

// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
        CollectionViewCell* cell = (CollectionViewCell*)[collectionView dequeueReusableCellWithReuseIdentifier:@"pagerCell" forIndexPath:indexPath];
        [cell.PagerViewCell addSubview:  [[[NSBundle mainBundle] loadNibNamed:@"AlbumsView" owner:self options:nil] objectAtIndex:0]];

    return cell;
}

- (CGSize)collectionView:(UICollectionView *)collectionView
                  layout:(UICollectionViewLayout*)collectionViewLayout
  sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
    return CGSizeMake(pagerView.frame.size.width    , pagerView.frame.size.height);
}

-(CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
    return 1;
}

- (void)viewWillLayoutSubviews
{
    [super viewWillLayoutSubviews];
    [pagerView.collectionViewLayout invalidateLayout];
}

并显示如下

单元格2

和Cell 3

Answer 1

在您的课程中添加此方法并进行更改直至您的需要。

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
    return UIEdgeInsetsMake(0, 0, 0, 0);
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
    return 10.0f;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{
    return 10.0f;
}

Answer 2

似乎没有设置要添加到集合视图单元格的子视图。问题出在这里：

// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
        CollectionViewCell* cell = (CollectionViewCell*)[collectionView dequeueReusableCellWithReuseIdentifier:@"pagerCell" forIndexPath:indexPath];
        [cell.PagerViewCell addSubview:  [[[NSBundle mainBundle] loadNibNamed:@"AlbumsView" owner:self options:nil] objectAtIndex:0]];

    return cell;
}

您只是在调用addSubview，但是您没有在要添加的子视图中添加任何类型的约束。它的外观如下：

// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
        CollectionViewCell* cell = (CollectionViewCell*)[collectionView dequeueReusableCellWithReuseIdentifier:@"pagerCell" forIndexPath:indexPath];
        UIView *albumsView = [[[NSBundle mainBundle] loadNibNamed:@"AlbumsView" owner:self options:nil] objectAtIndex:0]
        [cell.PagerViewCell addSubview: albumsView];

        // Adding constraints: 
        NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(albumsView);
        [cell.PagerViewCell addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[albumsView]|" options:0 metrics:nil views:viewsDictionary]];
        [cell.PagerViewCell addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[albumsView]|" options:0 metrics:nil views: viewsDictionary]];

    return cell;
}

约束使您的albumView填充单元格。据我所知，这是理想的效果。

如果您使用PureLayout之类的东西，那么约束部分看起来会更简单。

让我知道它是否适合你

Answer 3

你必须使用UICollectionView的委托方法， 你必须为每个Cell提及你的itemSize。

像这样创建一个UICollectionViewFlowLayout：

   UICollectionViewFlowLayout *layOut = [[UICollectionViewFlowLayout alloc] init]; 

   layOut.itemSize = CGSizeMake(cellWidth, cellHeight);

   layOut.scrollDirection = UICollectionViewScrollDirectionHorizontal;

   layOut.minimumInteritemSpacing = 0;

   layOut.minimumLineSpacing = 0;
   yourCollectionViewObject.collectionViewLayout = layOut;

并使用此委托方法：

-(CGSize)collectionView:(UICollectionView *)collectionView
              layout:(UICollectionViewLayout *)collectionViewLayout  sizeForItemAtIndexPath:(NSIndexPath *)indexPath

  {
     CGSize itemSize = CGSizeMake(cellWidth, cellHeight);

    return itemSize;
  }