Using Sections in TableView - ios

Question

How do you pass data from a tableview Controller with sections to a ViewController? I can do it when I'm not using sections, but the program crashes when I use sections? And I don't understand.
This is the error message I get and it cranes with a SIGABIT message on this line:
NSString *mytempName = [NSString stringWithString:[tempObject charName]];
Error message:
2014-07-24 06:38:05.465 Passing_Data_With_Two_Sections[469:60b] -[__NSArrayM charName]: unrecognized selector sent to instance 0x8f0d230
2014-07-24 06:38:05.501 Passing_Data_With_Two_Sections[469:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayM charName]: unrecognized selector sent to instance 0x8f0d230'
Here is the code from the TableView Controller
#import "myTableView.h"
#interface myTableView ()
#end
#implementation myTableView
NSMutableArray *myHeadersArray;
NSMutableArray *myFightersArray;
NSMutableArray *myLadiesArray;
NSMutableArray *myArray;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
myHeadersArray = [[NSMutableArray alloc]initWithObjects:#"Fighters", #"Ladies", nil];
myFightersArray = [[NSMutableArray alloc]init];
myLadiesArray = [[NSMutableArray alloc]init];
objectFile *myObject = [[objectFile alloc]init];
myObject.charName = #"Peter Pan";
[myFightersArray addObject:myObject];
myObject = [[objectFile alloc]init];
myObject.charName = #"Mikey Mouse";
[myFightersArray addObject:myObject];
myObject = [[objectFile alloc]init];
myObject.charName = #"Mrs Duck";
[myLadiesArray addObject:myObject];
myObject = [[objectFile alloc]init];
myObject.charName = #"Mini Mouse";
[myLadiesArray addObject:myObject];
myArray = [NSMutableArray arrayWithObjects:myFightersArray, myLadiesArray, nil];
[super viewDidLoad];
}
#pragma mark - Table view data source
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
return [myHeadersArray objectAtIndex:section];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return [myHeadersArray count];
//This seems to crash if you go above 2. Which I assume is somehow tied in with the sections.
//Adding additional names now no longer crash. But if I changed it to myArray then it crashes
//bitching it being greater 2.
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return [myArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"myCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"myCell" forIndexPath:indexPath];
if(cell == nil)
{
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
cell.textLabel.text = ((myTempObjectFile*)[[myArray objectAtIndex:indexPath.section] objectAtIndex:indexPath.row]).charName;
return cell;
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
ViewController *vc = [segue destinationViewController];
NSIndexPath *path = [self.tableView indexPathForSelectedRow];
int myrow = [path row];
myTempObjectFile *tv = [myArray objectAtIndex:myrow];
vc.tempObject = tv;
}
#end
And here is the code from my ViewController:
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize myLabelOutput;
#synthesize tempObject;
- (void)viewDidLoad
{
NSString *mytempName = [NSString stringWithString:[tempObject charName]];
[myLabelOutput setText:mytempName];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end

Answer 1

This happens because you try to invoke method charName for an array.
As I see you store arrays in array and you should change implementation to:
myTempObjectFile *tv = [[myArray objectAtIndex:indexPath.section] objectAtIndex:indexPath.row]
vc.tempObject = tv;
or just
myTempObjectFile *tv = myArray[indexPath.section][indexPath.row]
vc.tempObject = tv;
This answer to your question.
But I think that here we need to refactor: not very beautiful to store arrays in an array, it is better to make an abstract object for this data structure. And tempObject name does not bear any semantic meaning.