iOS table view with data from an NSDictionary

Question

I am new to iOS programming and I need some advice. I want to create a table view with sections to learn how it works. I have some objects from a model class user. I fill data in the table view using dictionaries. The table view is in a view Controller in my storyboard. The code works, but I don't know if this is a good way to handle the data in my table. Is this a semantic mistake to do this like I did?

Please take a Look at my code and give me some advice.

My user object (User.h):

@interface User : NSObject

@property (nonatomic, strong) NSString *email;
@property (nonatomic, strong) NSString *firstName;
@property (nonatomic, strong) NSString *lastName;
@property (nonatomic, strong) NSString *city;

@end

Dummy function to fill users into an array (in a helper class):

- (NSMutableArray *) createUser
{
    NSMutableArray *userArray = [[NSMutableArray alloc] init];

    User *user1 = [[User alloc] init];
    user1.firstName = @"Donald";
    user1.lastName = @"Duck";
    user1.email = @"donald_duck@disney.com";
    user1.city = @"Entenhausen";

    User *user2 = [[User alloc] init];
    user2.firstName = @"Micky";
    user2.lastName = @"Maus";
    user2.email = @"micky@disney.com";
    user2.city = @"Entenhausen";

    User *user3 = [[User alloc] init];
    user3.firstName = @"Daisy";
    user3.lastName = @"Duck";
    user3.email = @"daisy_duck@disney.com";
    user3.city = @"Frankfurt";

    User *user4 = [[User alloc] init];
    user4.firstName = @"Goofy";
    user4.lastName = @"Goof";
    user4.email = @"goofy@disney.com";
    user4.city = @"Berlin";

    User *user5 = [[User alloc] init];
    user5.firstName = @"Some";
    user5.lastName = @"Body";
    user5.email = @"somebody@disney.com";
    user5.city = @"Somewhere";

    User *user6 = [[User alloc] init];
    user6.firstName = @"Dagobert";
    user6.lastName = @"Duck";
    user6.email = @"dagobert@disney.com";
    user6.city = @"Mainz";

    [userArray addObject:user1];
    [userArray addObject:user2];
    [userArray addObject:user3];
    [userArray addObject:user4];
    [userArray addObject:user5];
    [userArray addObject:user6];

    return userArray;

}

Function to create a dictionary object (in a helper class):

- (NSMutableDictionary *) createDictionaryFromArray: (NSMutableArray *) allData
{
    NSArray *arrayKeys = [[NSArray alloc] initWithObjects:@"Entenhausen", @"Frankfurt", @"Berlin", @"Mainz", nil];

    NSMutableDictionary *collection = [[NSMutableDictionary alloc] init];

    for (int i=0; i < arrayKeys.count; i++) {
        NSString *key = [arrayKeys objectAtIndex:i];
        NSMutableArray *allValues = [[NSMutableArray alloc] init];

        for (User *usr in allData) {

            if([usr.city isEqualToString:key]) {
                [allValues addObject:usr];
            }
        }

        [collection setObject:allValues forKey:key];
    }

    return collection;
}

My table view controller class (TableViewController.h):

#import 
#import "HelperClass.h"

@interface TableViewController : UITableViewController  {
    HelperClass             *helper;
    NSMutableArray          *users;
    NSArray                 *allKeys;
    NSDictionary            *dictionaryUsers;
}

TableViewController.m:

#import "TableViewController.h"

@implementation TableViewController


- (void)viewDidLoad
{
    [super viewDidLoad];

    helper = [[HelperClass alloc] init];
    users = [[NSMutableArray alloc] init];
    users = [helper createUser];

    dictionaryUsers = [[NSMutableDictionary alloc] init];
    dictionaryUsers = [helper createDictionaryFromArray:users];
    allKeys = [NSArray array];
    allKeys = [dictionaryUsers allKeys];


}


#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{    // Return the number of sections.
    return [allKeys count];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    NSMutableArray *arrayValuesUsers = [[NSMutableArray alloc] init];
    arrayValuesUsers = [dictionaryUsers objectForKey:[allKeys objectAtIndex:section]];
    return [arrayValuesUsers count];
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {

    return [allKeys objectAtIndex:section];

}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell" forIndexPath:indexPath];

    User *user = [[User alloc] init];

    NSMutableArray *usersInSection = [dictionaryUsers objectForKey:[allKeys objectAtIndex:indexPath.section]];
    user = [usersInSection objectAtIndex:indexPath.row];

    cell.textLabel.text = [NSString stringWithFormat:@"%@, %@", user.lastName, user.firstName];
    cell.detailTextLabel.text = user.email;

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSMutableArray *usersInSection = [dictionaryUsers objectForKey:[allKeys objectAtIndex:indexPath.section]];
    User *usr = [usersInSection objectAtIndex:indexPath.row];

    NSLog(@"user: %@, %@", usr.lastName, usr.firstName);
}



@end

iOS table view with data from an NSDictionary

Answers (1)

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