Get row number of UITableview with multiple sections

Question

I have a UITableView, with multiple sections in it, and each section has multiple rows. I want to get the row number of selected cell with respect to the entire table and not the section only.

example:

1. I have two sections in the UITableView, section 1 has 3 rows and section 2 has 5 rows.
2. When I select sections 2's 2nd row, I should get the 5 as the row number in didSelectRowAtIndexPath method, rather than getting 2 as the row number (which is with respect to the section).

I tried to get the row number myself by doing the following, but it does not seem to work:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *selectedCell = [tableView cellForRowAtIndexPath:indexPath];

NSLog(@"%d",indexPath.row);

int theRow =  indexPath.row;

NSLog(@"%d",theRow);
}

I was thinking of storing the row number in an intvariable, and then add row numbers to it myself, but the code crashes when trying to store indexpath.row in theRow .

Please help. Thank you

Answer 1

NSInteger rowNumber = 0;

for (NSInteger i = 0; i < indexPath.section; i++) {
    rowNumber += [self tableView:tableView numberOfRowsInSection:i];
}

rowNumber += indexPath.row;

Answer 2

Here is a Swift adaption of the above answer by Wain

class func returnPositionForThisIndexPath(indexPath:NSIndexPath, insideThisTable theTable:UITableView)->Int{

    var i = 0
    var rowCount = 0

    while i < indexPath.section {

        rowCount += theTable.numberOfRowsInSection(i)

        i++
    }

    rowCount += indexPath.row

    return rowCount
}

Answer 3

Here's a cleaner implementation of this concept in Swift:

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) ->
    var rowNumber = indexPath.row
    for i in 0..<indexPath.section {
        rowNumber += self.tableView.numberOfRowsInSection(i)
    }

    // Do whatever here...
}

Answer 4

I had a big data set and the previous answers using for loops was causing performance issues for me in the lower sections. I ended up doing the calculating beforehand and sped things up a bit.

private var sectionCounts = [Int:Int]()

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    let number = fetchedResultsController.sections?[section].numberOfObjects ?? 0
    if section == 0 {
        sectionCounts[section] = number
    } else {
        sectionCounts[section] = number + (sectionCounts[section-1] ?? 0)
    }
    return number
}

func totalRowIndex(forIndexPath indexPath: NSIndexPath) -> Int {
    if indexPath.section == 0 {
        return indexPath.row
    } else {
        return (sectionCounts[indexPath.section-1] ?? 0) + indexPath.row
    }
}

Answer 5

The following is a Swiftier version of @Wain solution:

let rowNumber = Array(0..<indexPath.section).reduce(0) { $0 + tableView.numberOfRows(inSection: $1) } + indexPath.row

Answer 6

Let say I implement the code below in didSelectRowAt / didSelectItemAt callbacks ...

UITableView

var index: Int = indexPath.row
for i in 0..<indexPath.section {
    index += tableView.numberOfRows(inSection: i)
}

UICollectionView

var index: Int = indexPath.item
for i in 0..<indexPath.section {
    index += collectionView.numberOfItems(inSection: i)
}

Example: 2 sections, 3 rows(items) each. Selected row(item) 1 in the section 1, index = 4

Answer 7

i dont know about the multiple sections but i can give you for the one section...

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger index=indexPath.row;
NSString *string=[[NSString alloc]initWithFormat:@"%ld",(long)index];
}

from this you can get the row number and you can save it to the string....