如何在iOS中为uicollection视图单元设置动态大小？

Question

I am using uicollection view to display the images in grid view format.I am able to display the cells but the height & width is not increased for iPad it only display as the small blocks.Please tell me how can i make it dynamic.

[![enter image description here][1]][1]

I have used following code for make it dynamic.

pragma mark Collection view layout things

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
    if (collectionView==self.album_collection_view) {
        return 2.0;
    }
    else
        return 2.0;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
    if (collectionView==self.album_collection_view) {
        return 2.0;
    }
    else
        return 2.0;
}
// Layout: Set Edges
- (UIEdgeInsets)collectionView:
(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
    // return UIEdgeInsetsMake(0,8,0,8);  // top, left, bottom, right
    if (collectionView==self.album_collection_view) {
        return UIEdgeInsetsMake(5,0,0,0);
    }// top, left, bottom, right
    else
        return  UIEdgeInsetsMake(5,0,0,0);

}

Please tell me how can i resolve this issue?

Answer 1

here is the solution

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

YourCollectionCell * cell = (YourCollectionCell *) [YourCollectionViewObj cellForItemAtIndexPath:indexPath];

        if (cell == nil) {

            NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"YourCollectionCell" owner:self options:nil];
            cell = [topLevelObjects objectAtIndex:0];
            cell.frame = CGRectMake(0, 0, CGRectGetWidth(self.view.frame), 20);
            // SET YOUR CONTENT
            [cell layoutIfNeeded];

        }

        CGSize CellSize = [cell systemLayoutSizeFittingSize:UILayoutFittingCompressedSize withHorizontalFittingPriority:UILayoutPriorityDefaultHigh verticalFittingPriority:UILayoutPriorityDefaultLow];


        return CellSize;}

In case above solution not meet your needs,To obtain what you want, you should create your own UICollectionViewLayout (or maybe UICollectionViewFlowLayout) subclass, where you perform all the computations needed for placing every item in the right frame.

Take a look here for a great tutorial and here for something similar to what you want .

Answer 2

If you want to increase cell height and width you have to use sizeForItemAtIndexPath method. for that you have to add UICollectionViewDelegateFlowLayout delegate.

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(100, 100);
}