Question

I am working with a UITableView and for each of the objects in the array that is the datasource for the UITableView, I am deleting them if they meet a certain if statement. My problem is that it only deletes every-other object from the array.

Code:

UIImage *isCkDone = [UIImage imageNamed:@"UITableViewCellCheckmarkDone"];
int c = (tasks.count);
for (int i=0;i<c;++i) {
    NSIndexPath *tmpPath = [NSIndexPath indexPathForItem:i inSection:0];
    UITableViewCell * cell = [taskManager cellForRowAtIndexPath:tmpPath];
    if (cell.imageView.image == isCkDone) {
        [tasks removeObjectAtIndex:i];
        [taskManager deleteRowsAtIndexPaths:@[tmpPath]
                withRowAnimation:UITableViewRowAnimationLeft];
    }
}

What is wrong with this?

Answer 1

You must run your loop backwards, i.e.

for (int i=c-1;i>=0;--i)

If you are running it the other way round, removing an object at index position i moves the objects in the array that are behind i one position forward. In the end you will even run over the bounds of your array.