saving NSMutable Array Data - iphone

Question

I have a UITableView that is populated using a NSMutableArray . I am using xcode 4.2
the data in the NSMutable array stays in case I switch applications but it gets erased in these two cases :
1-the user switch view and come back .
2-the application is completley closed (i.e. the user double click on the Main button and remove it from the list of running application)
here is the code that I am using
-(NSString *)dataFilePath{
NSString *dataFilePath;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
NSString *documentDirectory = [paths objectAtIndex:0];
dataFilePath = [documentDirectory stringByAppendingPathComponent:#"Test App-Info.plist"];
return dataFilePath;
}
-(void)saveData{
[NSKeyedArchiver archiveRootObject:[data copy] toFile:[self dataFilePath]];
}
- (void)loadData
{
data = [NSKeyedUnarchiver unarchiveObjectWithFile:self.dataFilePath];
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
...
//saving the history
NSArray *archivedArray =[NSKeyedUnarchiver unarchiveObjectWithFile:[self dataFilePath]];
if (archivedArray == nil) {
data = [[NSMutableArray alloc] init];
}
else {
[self loadData];
[mainTableView reloadData];
}
}
Please let me know if I am missing something
Thanks
Edited :
the save data function is loaded in two locations :
1- the app that I am developing scans QR codes , so save data is called in the following function :
- (void) imagePickerController: (UIImagePickerController*) reader
didFinishPickingMediaWithInfo: (NSDictionary*) info
{
....
id<NSFastEnumeration> results =
[info objectForKey: ZBarReaderControllerResults];
ZBarSymbol *symbol = nil;
for(symbol in results){
// EXAMPLE: just grab the first barcode
break;
}
if(!symbol)
return;
// EXAMPLE: do something useful with the barcode data
theBarcodeString = symbol.data;
//adding the string to the list
[data addObject:theBarcodeString];
[self saveData];
[mainTableView reloadData];
[self endText];
stringLabel.text=theBarcodeString;
...
}
it is also called in when the data is edited :
-(IBAction)editTable{
UIBarButtonItem *leftItem;
[mainTableView setEditing:!mainTableView.editing animated:YES];
if (mainTableView.editing) {
leftItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:#selector(editTable)];
}
else {
leftItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemEdit target:self action:#selector(editTable)];
}
[self saveData];
[mainTableView reloadData];
}

Answer 1

You need to look into the following calls:
applicationDidEnterBackground
applicationWillEnterForeground
applicationDidBecomeActive
applicationWillTerminate
They are all methods of UIApplication. Your needs will dictate which of the above store and restore your data depending on when it should happen.