Ios UICollectionView每行显示3个项目

我有一个从故事板创建的UICollectionView

我希望视图中每行有3个项目。我通过以下方法做到了这一点：

    - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(collectionView.frame.size.width/3.6 , (collectionView.frame.size.height-100)/2);
}

但是，如果我有6个项目，那么我有2行，每个行有3个项目。 但当我有4个项目时，它将显示2行，每个行有2个项目

---

是否可以将它们显示为两行，第一行包含3个项目，第二行仅包含1个项目？

在这里我做到了，我在UICollectionView上实现了UICollectionViewDelegateFlowLayout添加以下方法。 它工作，使用它

- (CGSize)collectionView:(UICollectionView *)collectionView
                  layout:(UICollectionViewLayout *)collectionViewLayout
  sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    CGFloat screenWidth = screenRect.size.width;
    float cellWidth = screenWidth / 3.0; //Replace the divisor with the column count requirement. Make sure to have it in float.
    CGSize size = CGSizeMake(cellWidth, cellWidth);

    return size;
}

此方法的工作原理是屏幕大小宽度除以3

(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
  CGRect screenRect = [[UIScreen mainScreen] bounds];
  CGFloat screenWidth = screenRect.size.width;
  float cellWidth = screenWidth / 3.2; //Replace the divisor with the column count requirement. Make sure to have it in float.
  CGFloat screenHeight = screenRect.size.height;
  float cellHeight = screenHeight/3.0;


  CGSize size = CGSizeMake(cellWidth, cellHeight);


  return size;
}

也应用以下代码-（ViewWillTransitionOnToSize）

（void）视图将传递大小：（CGSize）带有传递协调器的大小：（id）协调器{
[self.collectionView/*（这是我的集合视图名称）*/reloadData]；
}

此代码将有助于在纵向模式和横向模式下获得相同数量的单元格。 我已经应用了上面的代码，在纵向模式下获得了3个单元格，在横向模式下获得了3个单元格。

试试这个

 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(self.view.frame.size.width/3 -10 , (collectionView.frame.size.height-100)/2);
}

---

我知道已经很晚了，但我目前使用的解决方案是使用KRLCollectionViewGridLayout，如下所示

        KRLCollectionViewGridLayout* aFlowLayout = [[KRLCollectionViewGridLayout alloc]init];
        aFlowLayout.aspectRatio = 1;
        aFlowLayout.sectionInset = UIEdgeInsetsMake(2, 2, 2, 2);
        aFlowLayout.interitemSpacing = 2;
        aFlowLayout.lineSpacing = 2;
        aFlowLayout.numberOfItemsPerLine = 3;
        aFlowLayout.scrollDirection = UICollectionViewScrollDirectionVertical;

        _collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width,self.view.frame.size.heigh) collectionViewLayout:aFlowLayout];

您可以使用以下命令找到KRLCollectionViewGridLayout库类

---

最重要的一点是，在collectionView的size inspector中，将单元格和行的最小间距设置为0。您需要首先计算内容的可用空间，然后将其除以每行要显示的项目数

下面是一个示例，假设

UICollectionView

占据了整个屏幕的宽度

private let numberOfItemPerRow = 2

private let screenWidth = UIScreen.main.bounds.width
private let sectionInset = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
private let minimumInteritemSpacing = CGFloat(10)
private let minimumLineSpacing = CGFloat(10)

// Calculate the item size based on the configuration above  
private var itemSize: CGSize {
    let interitemSpacesCount = numberOfItemPerRow - 1
    let interitemSpacingPerRow = minimumInteritemSpacing * CGFloat(interitemSpacesCount)
    let rowContentWidth = screenWidth - sectionInset.right - sectionInset.left - interitemSpacingPerRow

    let width = rowContentWidth / CGFloat(numberOfItemPerRow)
    let height = width // feel free to change the height to whatever you want 

    return CGSize(width: width, height: height)
}

最简单的方法

---

Swift 5

flowLayout.aspectRatio = 1
flowLayout.sectionInset = UIEdgeInsets(top: 2, left: 2, bottom: 2, right: 2)
flowLayout.interitemSpacing = 10
flowLayout.lineSpacing = 10
flowLayout.numberOfItemsPerLine = 4
flowLayout.scrollDirection = .vertical
self.collectionView.collectionViewLayout = flowLayout```

You can find KRLCollectionViewGridLayout library here -(https://github.com/klundberg/KRLCollectionViewGridLayout)

---

试试这个链接@PrashantTukadiya没有什么我可以用的，它仍然显示2行，每行2个项目，右边有一个空白（第一行有一个单元格）试试这个，你在故事板中为集合视图的单元格和行之间的间距设置了什么值？@AdeelMiraj 10每个项目只有4个项目，它将它们显示为2行，每行有2个单元格，我已经在这里尝试过了，CGSize size=CGSizeMake（100100）在give deault value中并尝试过。。（如果你可以在iphone 6或更高版本中试用，然后给出分辨率和设置大小的条件）这与手机无关，当我有6件物品时，一切都是完美的，但当我有4件物品时，收藏会将每一行的物品排列成相同的号码，我不知道这是否正常，或者我可以通过某种方式进行更改查看此链接：试试看

private let numberOfItemPerRow = 2

private let screenWidth = UIScreen.main.bounds.width
private let sectionInset = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
private let minimumInteritemSpacing = CGFloat(10)
private let minimumLineSpacing = CGFloat(10)

// Calculate the item size based on the configuration above  
private var itemSize: CGSize {
    let interitemSpacesCount = numberOfItemPerRow - 1
    let interitemSpacingPerRow = minimumInteritemSpacing * CGFloat(interitemSpacesCount)
    let rowContentWidth = screenWidth - sectionInset.right - sectionInset.left - interitemSpacingPerRow

    let width = rowContentWidth / CGFloat(numberOfItemPerRow)
    let height = width // feel free to change the height to whatever you want 

    return CGSize(width: width, height: height)
}

UICollectionViewFlowLayout *flowLayout = (UICollectionViewFlowLayout*)collectionView.collectionViewLayout;
flowLayout.sectionInset = UIEdgeInsetsMake(15, 15, 15, 15);

NSInteger itemRowCount = 3;
CGFloat rowWidth = collectionView.contentSize.width -  flowLayout.sectionInset.left - flowLayout.sectionInset.right;
CGFloat itemWidth = (rowWidth - flowLayout.minimumInteritemSpacing * (itemRowCount - 1) ) / itemRowCount;
CGFloat itemHeight = itemWidth / 3;
flowLayout.itemSize = CGSizeMake(itemWidth, itemHeight);

flowLayout.aspectRatio = 1
flowLayout.sectionInset = UIEdgeInsets(top: 2, left: 2, bottom: 2, right: 2)
flowLayout.interitemSpacing = 10
flowLayout.lineSpacing = 10
flowLayout.numberOfItemsPerLine = 4
flowLayout.scrollDirection = .vertical
self.collectionView.collectionViewLayout = flowLayout```

You can find KRLCollectionViewGridLayout library here -(https://github.com/klundberg/KRLCollectionViewGridLayout)