How to increment an NSIndexPath

Question

I have a data situation where I want to use an index path. As I'm traversing the data I want to increment the last node of an NSIndexPath. The code I have so far is:

int nbrIndex = [indexPath length];
NSUInteger *indexArray = (NSUInteger *)calloc(sizeof(NSUInteger),nbrIndex);
[indexPath getIndexes:indexArray];
indexArray[nbrIndex - 1]++;
[indexPath release];
indexPath = [[NSIndexPath alloc] initWithIndexes:indexArray length:nbrIndex];
free(indexArray);

This feels a bit, well, clunky - Is there a better way to do it?

score 6 · Accepted Answer · answered Mar 09 '12 at 15:01

6

You can try this - perhaps equally clunky, but at least a bit shorter:

NSInteger newLast = [indexPath indexAtPosition:indexPath.length-1]+1;
indexPath = [[indexPath indexPathByRemovingLastIndex] indexPathByAddingIndex:newLast];

answered Mar 09 '12 at 15:01

Sergey Kalinichenko

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Nice. I like it better because it avoid all the fluffing around with c arrays. THanks for that. – drekka Mar 10 '12 at 02:28

score 5 · Answer 2 · answered Aug 09 '12 at 02:25

5

One line less this way:

indexPath = [NSIndexPath indexPathForRow:indexPath.row+1 inSection:actualIndexPath.section];

answered Aug 09 '12 at 02:25

Rob Caraway

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This will work for table view index paths, but if I remember correctly I was considering a situation where the index path was for something else and longer than two nodes. – drekka Aug 10 '12 at 01:55

score 3 · Answer 3 · answered Oct 30 '15 at 08:19

Check my solution on Swift:

func incrementIndexPath(indexPath: NSIndexPath) -> NSIndexPath? {
    var nextIndexPath: NSIndexPath?
    let rowCount = numberOfRowsInSection(indexPath.section)
    let nextRow = indexPath.row + 1
    let currentSection = indexPath.section

    if nextRow < rowCount {
        nextIndexPath = NSIndexPath(forRow: nextRow, inSection: currentSection)
    }
    else {
        let nextSection = currentSection + 1
        if nextSection < numberOfSections {
            nextIndexPath = NSIndexPath(forRow: 0, inSection: nextSection)
        }
    }

    return nextIndexPath
}

score 1 · Answer 4 · answered Aug 31 '18 at 17:18

A for loop in Swift 4 achieving similar results with an embedded UITableView, iterating through the for loop, filling the detail text of a cell with "Row Updated"

for i in 0 ..< 9 {
     let nextRow = (indexPath?.row)! + i
     let currentSection = indexPath?.section
     let nextIndexPath = NSIndexPath(row: nextRow, section: currentSection!)

     embeddedViewController.tableView.cellForRow(at: nextIndexPath as IndexPath)?.detailTextLabel?.text = "Row Updated"

     let myTV = embeddedViewController.tableView
     myTV?.cellForRow(at: nextIndexPath as IndexPath)?.backgroundColor = UIColor.red
     myTV?.deselectRow(at: nextIndexPath as IndexPath, animated: true)                            
}

How to increment an NSIndexPath

4 Answers4