title: Access NSMutableArray from other existing class
body: <p>I'm trying to access a NSMutableArray from a different already existing class than it was created in. But if i NSLog it, i get null. My program starts up in class2, then I segue to class1, create my NSMutableArray by pressing one or more rows, and then I want my class2 to get the updated NSMutableArray instance, but all it get is null. Code below:</p>
  
  <pre><code>//class1.m
  
  #import "FocusTagTableViewController.h"
  #import "STATableViewController.h"
  
  @implementation FocusTagTableViewController
  
  @synthesize focusArray = _focusArray;
  @synthesize allSelectedFocus = _allSelectedFocus;
  
  - (void)viewDidLoad
  {
  _focusArray = [[NSArray alloc]initWithObjects:@"Balance",@"Bevægelse",@"Elementskift",@"Vejrtrækning",@"Alle",nil];
  
  [super viewDidLoad];
  
  }
  
  - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
  {
  NSString *selectedFocus = [[_focusArray objectAtIndex:indexPath.row] stringByAppendingString:@","];
  if(_allSelectedFocus == nil)
  {
      _allSelectedFocus = [[NSMutableArray alloc]init];
      [_allSelectedFocus addObject:selectedFocus]; 
  }
  else if(![_allSelectedFocus containsObject:selectedFocus])
  {
      [_allSelectedFocus addObject:selectedFocus];
  }
  }
  
  //class2.m
  
  #import "STATableViewController.h"
  #import "FocusTagTableViewController.h"
  
  @implementation STATableViewController
  - (void)viewDidLoad
  {
  [super viewDidLoad];
  
   FocusTagTableViewController *focusTag = [[FocusTagTableViewController alloc]init];
  
  [focustag addObserver:self forKeyPath:@"allSelectedFocus" options:NSKeyValueObservingOptionNew context:NULL];
  }
  
  -(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
  {
  if([keyPath isEqualToString:@"allSelectedFocus"])
  {
      NSLog(@"%@", [object valueForKeyPath:keyPath]);
  }
  }
  </code></pre>