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I am trying to create a collectionview with 3 items on every row in objective c. Here is my code:


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

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return items.count;
}

-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    
    collectionView.backgroundColor = [UIColor clearColor];
    
    NSString* buf = items[indexPath.row];
    
    CollectionCell *cell = (CollectionCell*)[collectionView dequeueReusableCellWithReuseIdentifier:@"CollectionCell" forIndexPath:indexPath];
    
    [cell loadCell:buf];
    
    CGRect screenBounds = [[UIScreen mainScreen] bounds];
    UIColor *leftColor = [UIColor colorWithRed:255.0/255.0 green:255.0/255.0 blue:255.0/255.0 alpha:0.5];
    cell.layer.cornerRadius = ((screenBounds.size.width)*0.25)/2;
    cell.layer.borderColor = leftColor.CGColor;
    cell.layer.borderWidth = 2;
    
    return cell;
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    CGRect screenBounds = [[UIScreen mainScreen] bounds];
    CGFloat boxWidth;
        boxWidth =  ((screenBounds.size.width)*0.25);
        bottomSpacing = 17;
    
    return CGSizeMake(boxWidth, boxWidth);
}

It look like the left but I want it to look like the right image.
enter image description here

What am I doing wrong and is it possible to fix it?

2

Answers


  1. To represent 3 columns with collectionview, each cell has to be width of 1/3 of the display. (Since 1/3 + 1/3 + 1/3 = 1)

    So try the code below, I have changed the width of the cell:

    - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
        CGRect screenBounds = [[UIScreen mainScreen] bounds];
        CGFloat boxWidth;
            boxWidth =  ((screenBounds.size.width)/3.0); //Change made here
            bottomSpacing = 17;
        
        return CGSizeMake(boxWidth, boxWidth);
    }
    
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  2. You can try this –

    CGSize itemSize = CGSizeMake(100, 100); // or whatever the size you want
    CGFloat minimumHorizontalSpacing = 10;
    CGFloat minimumVerticalSpacing = 10;
    CGFloat numberOfColumns = 3;
    
    - (UIEdgeInsets)collectionView:(UICollectionView *)collectionView 
                            layout:(UICollectionViewLayout *)collectionViewLayout 
            insetForSectionAtIndex:(NSInteger)section {
        
        CGFloat fullWidth = collectionView.bounds.size.width;
        CGFloat itemsWidth = (numberOfColumns * itemSize.width);
        CGFloat horizontalSpacing = ((numberOfColumns - 1) * minimumHorizontalSpacing);
        CGFloat itemsTotalWidth = (itemsWidth + horizontalSpacing);
        
        CGFloat horizontalInset = ((fullWidth - itemsTotalWidth) / 2);
        CGFloat verticalInset = 20;
        return UIEdgeInsetsMake(verticalInset, horizontalInset, verticalInset, horizontalInset)
    }
    
    - (CGSize)collectionView:(UICollectionView *)collectionView 
                      layout:(UICollectionViewLayout*)collectionViewLayout 
      sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
        return itemSize; 
    }
    
    - (CGFloat)collectionView:(UICollectionView *)collectionView 
                       layout:(UICollectionViewLayout *)collectionViewLayout 
    minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
        return minimumHorizontalSpacing;
    }
    
    - (CGFloat)collectionView:(UICollectionView *)collectionView 
                       layout:(UICollectionViewLayout *)collectionViewLayout 
    minimumLineSpacingForSectionAtIndex:(NSInteger)section {
        return minimumVerticalSpacing;
    }
    
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