Saving, retaining, & retrieving selected cells in array - ios

Question

I've read every post and tried every solution multiple times, but cannot get correct functionality.
I have a tableview with data from a local JSON file. I need the user to be able to:
select multiple cells
show check marks on selected cells
write those selections to an array
delete the selections when unchecked
5. save/retain the selections with the check marks when user switches view or leaves and comes back to tableview, closes and reopens app, etc.
I've managed to get 1-4 working, but I'm stuck on #5 and can't figure it out for the life of me. I've tried NSUserDefaults every way I could. Any help is appreciated. Below is the current code.
Also, why am I having to double click a cell to uncheck it?
#interface FilterViewController () <UISearchResultsUpdating>
#property (nonatomic, strong) NSArray *IngredientsArray;
#property (nonatomic, strong) UISearchController *searchController;
#property (nonatomic, strong) NSMutableArray *searchResults;
#property (nonatomic, strong) NSMutableArray *selectedCell;
#property (nonatomic, strong) NSMutableArray *selectedIngredients;
//I added this property to keep track of the selected row
#property (strong,nonatomic) NSIndexPath *selectedPath;
#end
#implementation FilterViewController {
NSArray *_locations;
}
- (void)viewDidLoad {
[super viewDidLoad];
self.selectedIngredients = [NSMutableArray array];
self.selectedCell = [NSMutableArray array];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
self.lastIndexPath = [defaults objectForKey:#"lastIndexPathUsed"];
// Create a new JSONLoader with a local file URL
JSONLoaderIngreds *jsonLoader = [[JSONLoaderIngreds alloc] init];
NSURL *url = [[NSBundle mainBundle] URLForResource:#"locations" withExtension:#"json"];
// There's no transition in our storyboard to our search results tableview or navigation controller
// so we'll have to grab it using the instantiateViewControllerWithIdentifier: method
UINavigationController *searchResultsController = [[self storyboard] instantiateViewControllerWithIdentifier:#"FilterViewSearchResultsNavController"];
// Our instance of UISearchController will use searchResults
self.searchController = [[UISearchController alloc] initWithSearchResultsController:searchResultsController];
// The searchcontroller's searchResultsUpdater property will contain our tableView.
self.searchController.searchResultsUpdater = self;
// create the searchBar programatically.
self.searchController.searchBar.frame = CGRectMake(self.searchController.searchBar.frame.origin.x,
self.searchController.searchBar.frame.origin.y,
self.searchController.searchBar.frame.size.width, 44.0);
self.tableView.tableHeaderView = self.searchController.searchBar;
//Sets LocationsViewController as presenter for LocationDetailViewController after searxh results dsiplayed
//and selected.. Required so searchbar doesn't show in detailsview after segue, and instead, default nav
//controller back button displays.
self.definesPresentationContext = true;
// Load the data on a background queue...
// As we are using a local file it's not really necessary, but if we were connecting to an online URL then we'd need it
//NSString *ingreds = [dict objectForKey:#"ingredients"]
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
_locations = [jsonLoader ingredientsFromJSONFile:url];
// Now that we have the data, reload the table data on the main UI thread
[self.tableView performSelectorOnMainThread:#selector(reloadData) withObject:nil waitUntilDone:YES];
});
}
// Just before showing the LocationViewController, set the selected Location object
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
LocationsViewController *vc = segue.destinationViewController;
NSIndexPath *indexPath = [self.tableView indexPathForCell:sender];
vc.location = [_locations objectAtIndex:indexPath.row];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (void)viewWillAppear:(BOOL)animated
{
//I added this if clause to select the row that was last selected
if (self.selectedPath != nil) {
[self.tableView selectRowAtIndexPath:self.selectedPath animated:NO scrollPosition:UITableViewScrollPositionNone];
}
}
#pragma mark - Table View Controller Methods
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
self.selectedPath = indexPath;
NSString *Ingredient = [_locations objectAtIndex:indexPath.row];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if([self isRowSelectedOnTableView:tableView atIndexPath:indexPath]){
[self.selectedCell removeObject:indexPath];
[self.selectedIngredients removeObject:Ingredient];
cell.accessoryType = UITableViewCellAccessoryNone;
} else {
[self.selectedCell addObject:indexPath];
[self.selectedIngredients addObject:Ingredient];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
NSLog(#"***************Selected Ingredients**************** %#", self.selectedIngredients);
NSUserDefaults *userdefaults = [NSUserDefaults standardUserDefaults];
[userdefaults setObject:[NSString stringWithFormat:#"%ld",(long)indexPath.section] forKey:#"lastIndexPathUsed"];
[userdefaults synchronize];
}
-(BOOL)isRowSelectedOnTableView:(UITableView *)tableView atIndexPath:(NSIndexPath *)indexPath
{
return ([self.selectedCell containsObject:indexPath]) ? YES : NO;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *unifiedID = #"FilterCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:unifiedID];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:unifiedID];
}
cell.textLabel.text = [_locations objectAtIndex:indexPath.row];
cell.imageView.image = [UIImage imageNamed:#"ingredientsicon3232.png"];
//if the indexPath was found among the selected ones, set the checkmark on the cell
cell.accessoryType = ([self isRowSelectedOnTableView:tableView atIndexPath:indexPath]) ? UITableViewCellAccessoryCheckmark : UITableViewCellAccessoryNone;
return cell;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [_locations count];
}
UPDATE:
I managed to changed code as suggested to save selections to array in NSUserDefaults using the updated code below, but I still can't figure out the cellForRowAtIndexPath code needed to save/recall checkmarks.
How would I code cellForRowAtIndexPath to recall checkmarks?
Saving selections to array with this code:
ViewDidLoad code:
_selections = [NSMutableArray arrayWithArray:(NSArray *)[[NSUserDefaults standardUserDefaults] objectForKey:#"selections"]];
if(_selections == nil){
_selections = [[NSMutableArray alloc] init];
}
didSelectRowAtIndexPath code:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
{
if ([_selections containsObject: cell.textLabel.text] == NO){
[_selections addObject:cell.textLabel.text];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
} else {
[_selections removeObject:cell.textLabel.text];
cell.accessoryType = UITableViewCellAccessoryNone;
}
NSLog(#"***************Selected Ingredients**************** %#", _selections);
NSUserDefaults *userdefaults = [NSUserDefaults standardUserDefaults];
[userdefaults setObject:_selections forKey:#"selections"];
[userdefaults synchronize];
NSLog(#"-------------NSUserDefaults------------%#", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation])
}

Answer 1

Your solution is pretty straight forward.
First thing is you need to save an array of selected index paths to your user default object instead of just last selected path.
Whenever a user selects or deselects a row. Add and remove objects from the same array and save it back to your user defaults.
In your cellForRowAtIndexPath, check whether your index path exists in the array saved in the user defaults. If it exists, select the row with checkmark otherwise leave it as it is.
Hope this helps.

Answer 2

I think instead of working with those indexPath, i recommended you to work straight with the data itself, add a Bool property to indicate the selection in your Ingredient class, then save the whole array in CoreData/Realm/NSUserDefault, that way is more correctly since your data can be change, lead to the selection indexPath that you save can be not correct anymore