Code for SO question: Checkbox in UITableView Cell

// this is an answer for SO question http://stackoverflow.com/q/21859288/1449607

@interface TableViewController : UITableViewController

@end

@interface TableViewController ()
@property (nonatomic, strong) NSMutableArray* books;
@property (nonatomic, strong) NSString* path;
@end

@implementation TableViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    
    self.path = [documentsDirectory stringByAppendingPathComponent:@"books.plist"];
    // Attempt to load saved data from the documents directory
    if ([[NSFileManager defaultManager] fileExistsAtPath:self.path]){
        self.books = [NSMutableArray arrayWithContentsOfFile:self.path];
    }else{
        // No saved data in documents directory so we need to load the data from the bundle
        NSString* bundlePath = [[NSBundle mainBundle] pathForResource:@"books" ofType:@"plist"];
        self.books = [NSMutableArray arrayWithContentsOfFile:bundlePath];
    }
}

#pragma mark - Table view data source

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return self.books.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
    
    if (cell == nil){
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier];
    }
    
    NSDictionary* book = self.books[indexPath.row];
    cell.accessoryType = [book[@"checkbox"] boolValue] ? UITableViewCellAccessoryCheckmark : UITableViewCellAccessoryNone;
    cell.textLabel.text = book[@"title"];
    cell.detailTextLabel.text = book[@"price"];
    cell.imageView.image = [UIImage imageWithContentsOfFile:book[@"thumbnail"]];
    return cell;
}

-(void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    NSMutableDictionary* book = self.books[indexPath.row];
    book[@"checkbox"] = [NSNumber numberWithBool:[book[@"checkbox"] boolValue]];
    
    [self.books writeToFile:self.path atomically:YES];
    
    [tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}

@end