Why does Section data reset each time? - ios

Question

I'm quite new to iOS development (as you'll see from my code below). I like to help myself learn new languages by manipulating existing code to do something different. I've hit a bit of a blank with this one though. At the end of each section in a table view, the data it is using resets and it starts again, instead of carrying on. Can anyone tell me where the fault lies here please?
#import "RootViewController.h"
#import "DataController.h"
#import "DetailViewController.h"
#import "Play.h"
#implementation RootViewController
#synthesize dataController;
#synthesize play;
#pragma mark -
#pragma mark View lifecycle
- (void)viewDidLoad {
[super viewDidLoad];
self.title = NSLocalizedString(#"Plays", #"Master view navigation title");
}
#pragma mark -
#pragma mark Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// Only one section.
return 3;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
/*
The number of rows varies by section.
*/
NSInteger rows = 0;
switch (section) {
case 0:
rows = 3;
break;
case 1:
rows = 1;
break;
case 2:
rows = 2;
break;
default:
break;
}
return rows;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath
*)indexPath {
static NSString *CellIdentifier = #"PlayCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
// Get the object to display and set the value in the cell.
Play *playAtIndex = [dataController objectInListAtIndex:indexPath.row];
cell.textLabel.text = playAtIndex.title;
return cell;
}
// Section header titles
#pragma mark -
#pragma mark Section header titles
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:
(NSInteger)section {
NSString *secttitle = nil;
switch (section) {
case 0:
secttitle = NSLocalizedString(#"Comedy", #"Comedy section title");
break;
case 1:
secttitle = NSLocalizedString(#"Action", #"Action section title");
break;
case 2:
secttitle = NSLocalizedString(#"Drama", #"Drama section title");
break;
default:
break;
}
return secttitle;
}
// End of section header titles
#pragma mark -
#pragma mark Table view selection
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
/*
When a row is selected, the segue creates the detail view controller as the destination.
Set the detail view controller's detail item to the item associated with the selected
row.
*/
if ([[segue identifier] isEqualToString:#"ShowSelectedPlay"]) {
NSIndexPath *selectedRowIndex = [self.tableView indexPathForSelectedRow];
DetailViewController *detailViewController = [segue destinationViewController];
detailViewController.play = [dataController objectInListAtIndex:selectedRowIndex.row];
}
}
#end
Thanks for your replies so far. The Detail view works fine, and judging by your feedback so far it appears it's because this code isn't being evaluated, but I can't seem to work out where to incorporate it in the master view.
NSString *cellText = nil;
switch (indexPath.section) {
case 0:
cellText = play.date;
break;
case 1:
cellText = play.genre;
break;
case 2:
cellText = [play.characters objectAtIndex:indexPath.row];
break;
default:
break;
}
cell.textLabel.text = cellText;
return cell;

Answer 1

Because you're only using the indexPath.row to get your cell content. Your data model should also consider the indexPath.section:
Play *playAtIndex = [dataController objectInListAtIndex:indexPath.row];
cell.textLabel.text = playAtIndex.title;
i.e. you have a one-dimensional data model...

Answer 2

This line:
Play *playAtIndex = [dataController objectInListAtIndex:indexPath.row];
only takes into account the current indexPath's row, which also resets to zero at the beginning of each section. You'll need to use an array of arrays or otherwise account for the rows in previous sections to get the correct index.