问题

I have a UICollectionView created from storyboard,

I want to have 3 items per row in the view. I managed to do that using the following:

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

However, if i have 6 items, i got 2 rows with 3 items each. But when i have 4 items, it will display 2 rows with 2 items each.

Is it possible to display them in 2 rows, the first with 3 items and the second contains only 1?

回答1:

here i did it , i implemented UICollectionViewDelegateFlowLayout on UICollectionView add following method . it work , use it .

- (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;
}

this method work as screen size width divided by 3 .

回答2:

(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;
}

Apply the below code too-(viewWillTransitionToSize)

(void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
  [self.collectionView/*(that's my collection view name)*/ reloadData];
}

This Code will help to get the same no. of cells in portrait as well as in landscape mode also. I have applied above code to get 3 cells in portrait as well as 3 cells in landscape mode.

回答3:

try this

 - (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);
}

回答4:

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
    return CGSizeMake(self.collectionView.bounds.size.width/3, self.collectionView.bounds.size.width/3);
}

Most important thing need to do as well is in size inspector of collectionView set up the minimum spacing for cell & line to 0

回答5:

You need to calculate first the available space for the content and then divide that by the number of items you want to present per row.

Here is an example assuming that the UICollectionView is taking all the width of the screen

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)
}

回答6:

Easiest way

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);

回答7:

I know it is so late, but the solution that i am currently using and handled this case was by using KRLCollectionViewGridLayout as below

        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];

You can find KRLCollectionViewGridLayout library class using this link

来源：https://stackoverflow.com/questions/34116251/uicollectionview-display-3-items-per-row

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ios