Retrieving and re-saving an nsmutablearray to nsuserdefaults from a uitableview - ios

Question

I have a uitableview with a list of items populated from a JSON file located locally within the app. Everything works as far as getting the list to the table and the multiple selection of items which when selected (or deselected) are then saved to a nsmutablearray.
The problem is when the user leaves the view and returns and selects another item (or deselects a currently selected item). At this point the mutable array is then empty.
I'm not sure if the nsuserdefaults saving of the mutable array is the problem. it saves it fine but then when the view reappears (the mutable array's value is fine at this point) and the user touches a table row the array is null once more.
my .h file:
#interface CategoriesViewController : UITableViewController {
NSMutableArray *_selectedItems;
NSString *filePath;
NSString *string;
}
// arForTable array will hold the JSON results from the api
#property (nonatomic, retain) NSArray *arForTable;
#property (nonatomic, retain) NSMutableArray *categorySelected;
#property (nonatomic, retain) NSString *jsonStringCategory;
#property(nonatomic, retain) UIView *accessoryView;
#end
my .m file:
#implementation CategoriesViewController
#synthesize arForTable = _arForTable;
- (void)viewDidLoad
{
[super viewDidLoad];
self.categorySelected = [[NSMutableArray alloc] init];
[self reloadMain];
// assignment reference so don't release
_selectedItems = [(AppDelegate *)[[UIApplication sharedApplication] delegate] selectedCategories];
self.tableView.hidden = NO;
}
-(void) reloadMain {
// countrySaved value from NSUserDefaults
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
NSString *countryString = [defaults stringForKey:#"selectedCountryTableString"];
NSString *cityString = [defaults stringForKey:#"selectedCityTableString"];
NSLog(#"countrystring from category is %#", countryString);
NSLog(#"citystring from category is %#", cityString);
// getting path to the file
if ([defaults stringForKey:#"selectedCountryTableString"] == NULL) {
filePath = [[NSBundle mainBundle] pathForResource:#"categoriesit" ofType:#"json"];
} else if ([countryString isEqualToString:#"UK"]) {
filePath = [[NSBundle mainBundle] pathForResource:#"categoriesuk" ofType:#"json"];
} else if ([countryString isEqualToString:#"Italy"]) {
filePath = [[NSBundle mainBundle] pathForResource:#"categoriesit" ofType:#"json"];
} else if ([countryString isEqualToString:#"Spain"]) {
filePath = [[NSBundle mainBundle] pathForResource:#"categorieses" ofType:#"json"];
} else if ([countryString isEqualToString:#"Brazil"]) {
filePath = [[NSBundle mainBundle] pathForResource:#"categoriesbr" ofType:#"json"];
}
NSString *fileContent = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
//NSLog(#"File content: %#", fileContent);
// creating new parser
SBJSON *parser = [[SBJSON alloc] init];
// parsing the first level
NSDictionary *data = (NSDictionary *) [parser objectWithString:fileContent error:nil];
NSDictionary *menu = (NSDictionary *) [data objectForKey:#"menu"];
#ifdef DEBUG
NSLog(#"menu is %#",menu);
#endif
NSMutableArray *itemsTMP = [[NSMutableArray alloc] init];
NSData *jsonData = [NSData dataWithContentsOfFile:filePath];
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:nil error:nil];
// NSLog(#"results File test %#",dict);
itemsTMP = [dict objectForKey:#"results"];
// NSLog(#"itemsTMPitemsTMP File test %#",itemsTMP);
self.arForTable = [itemsTMP copy];
[self.tableView reloadData];
}
#pragma mark - Table view data source
- (int)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (int)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [self.arForTable count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
[cell.textLabel setFont:[UIFont fontWithName: #"Asap-Bold" size: 14.0f]];
[cell.detailTextLabel setFont:[UIFont fontWithName: #"Asap-Bold" size: 14.0f]];
cell.selectedBackgroundView = [[UIView alloc] initWithFrame:CGRectZero];
cell.selectedBackgroundView.backgroundColor = [UIColor colorWithRed:204.0/255.0 green:56.0/255.0 blue:55.0/255.0 alpha:1];
}
UIImageView *cellAccessoryImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"icon-tick.png"]] ;
UIImageView *cellAccessoryNoneImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#""]] ;
if([_selectedItems containsObject:indexPath]){
cell.accessoryView = cellAccessoryImageView;
} else {
cell.accessoryView = cellAccessoryNoneImageView;
}
// Get item from tableData
NSDictionary *item = (NSDictionary *)[_arForTable objectAtIndex:indexPath.row];
// encoding fix
NSString *correctStringTitle = [NSString stringWithCString:[[item objectForKey:#"key"] cStringUsingEncoding:NSISOLatin1StringEncoding] encoding:NSUTF8StringEncoding];
cell.textLabel.text = [correctStringTitle capitalizedString];
NSNumber *num = [item objectForKey:#"id"];
cell.detailTextLabel.text = [num stringValue];
cell.detailTextLabel.hidden = YES;
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[tableView deselectRowAtIndexPath:indexPath animated:YES];
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
if([_selectedItems containsObject:indexPath]){
[_selectedItems removeObject:indexPath];
[self.categorySelected removeObject:[[self.arForTable objectAtIndex:indexPath.row] objectForKey:#"id"]];
string = [self.categorySelected componentsJoinedByString:#","];
[defaults setObject:string forKey:#"selectedCategoryTableString"];
NSLog(#"%# defaults from did select remove categorySelected",[defaults stringForKey:#"selectedCategoryTableString"]);
NSLog(#"%# STRING FROM contains / removeObj",string);
} else {
[_selectedItems addObject:indexPath];
[self.categorySelected addObject:[[self.arForTable objectAtIndex:indexPath.row] objectForKey:#"id"]];
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
string = [self.categorySelected componentsJoinedByString:#","];
[defaults setObject:string forKey:#"selectedCategoryTableString"];
NSLog(#"%# providerSelected from did select add ",self.categorySelected);
NSLog(#"%# STRING FROM contains / addObj",string);
}
[tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
// [tableView reloadData];
}
-(void) viewWillAppear:(BOOL)animated {
[super viewWillAppear:NO];
[self.navigationController setNavigationBarHidden:YES animated:NO];
self.navigationController.toolbarHidden = YES;
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
// NSLog(#"ALL DEFAULTS %#", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);
NSLog(#"%# defaults from view appear categorySelected",[defaults stringForKey:#"selectedCategoryTableString"]);
string = [defaults stringForKey:#"selectedCategoryTableString"];
NSLog(#"%# STRING from will appear",string);
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
also in the app delegate I have in the .h:
#property (strong, nonatomic) NSMutableArray *selectedCategories;
and in the .m:
`_selectedCategories = [NSMutableArray new];
in the didFinishLaunchingWithOptions: method
just to be clear:
when the view appears again (if I nslog the output) the mutablearray has been saved and is retrieved correctly. the mutable array only clears itself when a tablerow is touched again.
thanks if anyone can help with this. I've been stuck on it for some time...

Answer 1

edit
// DONT EVER EVER EVER EVER EVER EVER DO THIS!!!
// We don't use types as variable names, that is implicit...
// I get it, this is a string, BUT WHAT IS IT A STRING OF, the name
// 'string' does you, and anyone else, no good. Think about all your
// code like you are writing it for someone else, because when you come
// back to it in 6 months, you will be someone else, and you won't know
// what this means
NSString *string;
end edit
I would not be using NSUserDefaults this way. You have already parsed JSON into an archiveable object (NSMutableArray). In viewDidLoad, you should probably try doing something like:
-(void)viewDidLoad
{
// Load the array from a plist file
self.dataYouNeed = [NSMutableArray arrayWithContentsOfFile:#"someFileName.plist"];
// If we got back nil, that file didn't exist, so call 'reloadMain',
// do your parsing there THEN SAVE to a plist using:
//
// [myArray writeToFile:#"someFileName.plist"]
//
if(self.dataYouNeed == nil) [self reloadMain];
// Then do the exact same thing when you try to persist your selection...
// aka do not store a CSV string, just store an Array, and call writeToFile:
// when you want to save, and arrayWithContentsOfFile when you want to read
// it back in
}
On top of that, depending on where your data is coming from, I would move all of your data out of the JSON files and set it up in a plist, then you can ditch all of your parsing code.... :). Basically I am saying this is all a little too complicated for such a simple task, make your own life easier.
edit
You may have an issue with not using 'self.string', simply referring to 'string' is dangerous, you are creating a new reference everytime. This is most likely creating a memory leak. (ARC is not magic, it can not handle ALL memory management for you)
edit
Ok, so re-reading your code, I noticed a few things.
1. Why do you store your CSV string in the 'string' instance var?
This is somewhat redundant. At no point do you ever read from this variable without having set it in the few lines of code before. It should just be an NSString declared with in the scope of the method.
2. Are you expecting '_selectedItems' to have retained your reference to the 'selectedCategories' array on your AppDelegate?
You can not make this assumption, especially without having made a #property declaration. ARC does not know how to handle it and will probably be releasing the reference when you leave the view. The more likely possibility is that you are creating a memory leak every time you set that variable. You can also not guarantee that viewDidLoad will be called again to reset the reference. You should probably be setting this in viewWillAppear.
3. Which NSMutableArray are you experiencing a nil reference to?
If it is '_selectedItems', consider #2. If it is 'categorySelected', this is also probably being released when this view disappears. If this is really what you are trying to persist, then why are you not populating it from the viewDidAppear method. The only thing you do in viewDidAppear is set the 'string' variable (which is never actually read from, like #1 says). Did you mean to set 'categorySelected' here? I believe you meant to get your list from NSUserDefaults, then populate 'categorySelected' using that string's componentsSeparatedByString: method, which returns an array

Answer 2

Every time a user goes to some other view and comes back then
self.categorySelected = [[NSMutableArray alloc] init]; gets executed resulting it to an empty array.

Answer 3

First serialize the array when leaving the view:
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:#[#"1",#"2",#"3"]];
[[NSUserDefaults standardUserDefaults] setObject:data forKey:#"myarray"];
[[NSUserDefaults standardUserDefaults] synchronize];
Then deserialize it when you are back to that view:
NSData *data = [[NSUserDefaults standardUserDefaults] objectForKey:#"myarray"];
NSArray *myarray = [NSKeyedUnarchiver unarchiveObjectWithData:data];
NSLog(#"MYARRAY %#", myarray);
Note: if key is not found then init a new array.

Answer 4

Can you try to change 'retain' to 'strong' here?
#property (nonatomic, retain) NSMutableArray *categorySelected;

Answer 5

I think the issue is, you are setting the selectedItems array in viewDidLoad method. Probably the viewDidLoad is working once.
Just add the following line in your viewWillAppear method:
_selectedItems = [(AppDelegate *)[[UIApplication sharedApplication] delegate] selectedCategories];