How to get number of rows in a section in ios

Question

I am working on collection view and I want number of rows in previous section. Is there any method which return number of row in section. Please help me.

Answer 1

The delegate method of the UICollectionView dataSource that you will need to implement in order to display the cells can be invoked manually.

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section

Therefore you can call it using:

NSInteger numberOfRows = [self collectionView:self.collectionView numberOfItemsInSection:MAX(0, currentSection - 1)];

You do not want to get an out of bounds exception so I have capped it at 0*

EDIT

@holex raises a very good point - I was assuming you only had one column.

If you know the size of your items width you can do the following:

//Assuming a fixed width cell

NSInteger section = 0;
NSInteger totalItemsInSection = [self.feedCollectionView numberOfItemsInSection:section];

UIEdgeInsets collectionViewInset = self.feedCollectionView.collectionViewLayout.sectionInset;
CGFloat collectionViewWidth = CGRectGetWidth(self.feedCollectionView.frame) - collectionViewInset.left - collectionViewInset.right;
CGFloat cellWidth = [self.feedCollectionView.collectionViewLayout itemSize].width;
CGFloat cellSpacing = [self.feedCollectionView.collectionViewLayout minimumInteritemSpacing];

NSInteger totalItemsInRow = floor((CGFloat)collectionViewWidth / (cellWidth + cellSpacing));
NSInteger numberOfRows = ceil((CGFloat)totalItemsInSection / totalItemsInRow);

NSLog(@"%@", @(numberOfRows));

We determine how many items will appear in a row, to be a able to determine the amount of rows in the section.

Answer 2

There are two method in collectionview, notice that the method are not in the delegate of collectionview.

- (NSInteger)numberOfSections;
- (NSInteger)numberOfItemsInSection:(NSInteger)section;

You can call [self.collectionView numberOfSections]; to find the sectionCount.

You can call [self.collectionView numberOfItemsInSection:somesection]; to find the rows in some section.