如何在 objective c 中的每一行创建一个包含 3 个单元格的集合视图

Question

我正在尝试在 objective c 中的每一行创建一个包含 3 个项目的集合视图。这是我的代码：


-(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);
}

它看起来像左图，但我希望它看起来像右图。

我做错了什么，是否可以解决？

Answer 1

要用 collectionview 表示 3 列，每个单元格的宽度必须是显示的 1/3。（因为 1/3 + 1/3 + 1/3 = 1）

所以试试下面的代码，我改变了单元格的宽度：

- (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);
}

Answer 2

你可以试试这个-

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;
}

如何在 objective c 中的每一行创建一个包含 3 个单元格的集合视图

How to create a collectionview with 3 cells on every row in objective c

xcode

objective-c

ios