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gregdodd
8,124 PointsObjectAtIndex:indexPath.row Confusion
I'm not sure if I missed it somewhere, but I'm having trouble understanding this one line: cell.textLabel.text = [self.titles objectAtIndex:indexPath.row]; How does the indexPath.row work to apply each title to a row? Specifically, what is row doing?
4 Answers
Stone Preston
42,016 PointsNSIndexPath has 2 properties, row and section. Row tells you the row number, and section tells you the section number. (although a lot of the time you only use row if you only have 1 section in your tableView, which is the case for many tableViews)
the tableView delegate method includes indexPath as a parameter of the method. you use that parameter here:
cell.textLabel.text = [self.titles objectAtIndex:indexPath.row]
so the tableView uses the row of the table to index your array, giving each cell a title based on the data in array.
the first row's indexPath.row is 0, so it uses the first element in the array as the title, the second row's indexPath.row is 1, so it uses the 2nd element in the array as the title, the third row's indexPath.row is 2, so it uses the 3rd element in the array as the title etc etc.
gregdodd
8,124 PointsOk I think I got it. So it's getting the value for its row number from the previous method, and then counting through them while applying the titles?
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return [self.titles count];
}
Stone Preston
42,016 Pointseh sort of. That numberOfRows method lets the tableView know how many rows there need to be, but I wouldnt say that it gets its indexPath.row number from that numberOfRows method since that numberOfRows method just returns then length of the array.
gregdodd
8,124 PointsHmm, I guess I'm just still stuck on how each title gets assigned to a cell and where that happens in the table view controller. In Java I was used to running a for loop to work through arrays and assign data.
Stone Preston
42,016 Pointswell the cellForRowAtIndexPath tableView delegate method is what does that. It gets called for each row in the table. and inside that method you have code for specifying what goes in the cell, and it uses the indexPath.row to index your array to get data.
gregdodd
8,124 PointsAh I see now. Thanks!