View CoreData in TableView and export to windows share

Discussion in 'iOS Programming' started by stefansaeys, Jul 31, 2014.

  1. stefansaeys macrumors newbie

    Joined:
    Jul 30, 2014
    #1
    The goal is to add data on first screen, show list at the second screen and from this second screen export data to a Windows share (ip_address) in CSV format. Currently the list on the second screen is empty. Any help really appreciated.
    I've also made the full project available for download.


    CoreDataViewController.h
    Code:
    #import <UIKit/UIKit.h>
    #import "CoreDataAppDelegate.h"
    
    @interface CoreDataViewController : UIViewController
    @property (weak, nonatomic) IBOutlet UITextField *name;
    @property (weak, nonatomic) IBOutlet UILabel *status;
    - (IBAction)saveData:(id)sender;
    - (IBAction)findContact:(id)sender;
    
    @end
    
    CoreDataViewController.m
    Code:
    #import "CoreDataViewController.h"
    
    @interface CoreDataViewController ()
    
    @end
    
    @implementation CoreDataViewController
    
    - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
    {
        self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
        if (self) {
            // Custom initialization
        }
        return self;
    }
    
    - (void)viewDidLoad
    {
        [super viewDidLoad];
    	// Do any additional setup after loading the view.
    }
    
    - (void)didReceiveMemoryWarning
    {
        [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.
    }
    
    - (IBAction)saveData:(id)sender {
        CoreDataAppDelegate *appDelegate =
        [[UIApplication sharedApplication] delegate];
    
       NSManagedObjectContext *context =
        [appDelegate managedObjectContext];
       NSManagedObject *newContact;
       newContact = [NSEntityDescription
           insertNewObjectForEntityForName:@"Contacts"
           inManagedObjectContext:context];
       [newContact setValue: _name.text forKey:@"name"];
    
       _name.text = @"";
    
       NSError *error;
       [context save:&error];
       _status.text = @"Contact saved";
    
    }
    
    - (IBAction)findContact:(id)sender {
        CoreDataAppDelegate *appDelegate =
           [[UIApplication sharedApplication] delegate];
    
        NSManagedObjectContext *context =
           [appDelegate managedObjectContext];
    
        NSEntityDescription *entityDesc =
           [NSEntityDescription entityForName:@"Contacts"
           inManagedObjectContext:context];
    
        NSFetchRequest *request = [[NSFetchRequest alloc] init];
        [request setEntity:entityDesc];
    
        NSPredicate *pred =
           [NSPredicate predicateWithFormat:@"(name = %@)",
            _name.text];
        [request setPredicate:pred];
        NSManagedObject *matches = nil;
    
        NSError *error;
        NSArray *objects = [context executeFetchRequest:request
            error:&error];
    
        if ([objects count] == 0) {
           _status.text = @"No matches";
        } else {
           matches = objects[0];
           _status.text = [NSString stringWithFormat:
               @"%lu matches found", (unsigned long)[objects count]];
        }
    }
    @end
    
    CoreDataAppDelegate.h
    Code:
    #import <UIKit/UIKit.h>
    
    @interface CoreDataAppDelegate : UIResponder <UIApplicationDelegate>
    
    @property (strong, nonatomic) UIWindow *window;
    
    @property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
    @property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
    @property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
    
    - (void)saveContext;
    - (NSURL *)applicationDocumentsDirectory;
    
    @end
    
    CoreDataAppDelegate.m
    Code:
    #import "CoreDataAppDelegate.h"
    
    @implementation CoreDataAppDelegate
    
    @synthesize managedObjectContext = _managedObjectContext;
    @synthesize managedObjectModel = _managedObjectModel;
    @synthesize persistentStoreCoordinator = _persistentStoreCoordinator;
    
    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {
        return YES;
    }
    
    - (void)applicationWillResignActive:(UIApplication *)application
    {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
    }
    
    - (void)applicationDidEnterBackground:(UIApplication *)application
    {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }
    
    - (void)applicationWillEnterForeground:(UIApplication *)application
    {
        // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
    }
    
    - (void)applicationDidBecomeActive:(UIApplication *)application
    {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }
    
    - (void)applicationWillTerminate:(UIApplication *)application
    {
        // Saves changes in the application's managed object context before the application terminates.
        [self saveContext];
    }
    
    - (void)saveContext
    {
        NSError *error = nil;
        NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
        if (managedObjectContext != nil) {
            if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
                 // Replace this implementation with code to handle the error appropriately.
                 // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
                NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
                abort();
            } 
        }
    }
    
    #pragma mark - Core Data stack
    
    // Returns the managed object context for the application.
    // If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
    - (NSManagedObjectContext *)managedObjectContext
    {
        if (_managedObjectContext != nil) {
            return _managedObjectContext;
        }
        
        NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
        if (coordinator != nil) {
            _managedObjectContext = [[NSManagedObjectContext alloc] init];
            [_managedObjectContext setPersistentStoreCoordinator:coordinator];
        }
        return _managedObjectContext;
    }
    
    // Returns the managed object model for the application.
    // If the model doesn't already exist, it is created from the application's model.
    - (NSManagedObjectModel *)managedObjectModel
    {
        if (_managedObjectModel != nil) {
            return _managedObjectModel;
        }
        NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"CoreData" withExtension:@"momd"];
        _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
        return _managedObjectModel;
    }
    
    // Returns the persistent store coordinator for the application.
    // If the coordinator doesn't already exist, it is created and the application's store added to it.
    - (NSPersistentStoreCoordinator *)persistentStoreCoordinator
    {
        if (_persistentStoreCoordinator != nil) {
            return _persistentStoreCoordinator;
        }
        
        NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"CoreData.sqlite"];
        
        NSError *error = nil;
        _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
        if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
            /*
             Replace this implementation with code to handle the error appropriately.
             
             abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
             
             Typical reasons for an error here include:
             * The persistent store is not accessible;
             * The schema for the persistent store is incompatible with current managed object model.
             Check the error message to determine what the actual problem was.
             
             
             If the persistent store is not accessible, there is typically something wrong with the file path. Often, a file URL is pointing into the application's resources directory instead of a writeable directory.
             
             If you encounter schema incompatibility errors during development, you can reduce their frequency by:
             * Simply deleting the existing store:
             [[NSFileManager defaultManager] removeItemAtURL:storeURL error:nil]
             
             * Performing automatic lightweight migration by passing the following dictionary as the options parameter:
             @{NSMigratePersistentStoresAutomaticallyOption:@YES, NSInferMappingModelAutomaticallyOption:@YES}
             
             Lightweight migration will only work for a limited set of schema changes; consult "Core Data Model Versioning and Data Migration Programming Guide" for details.
             
             */
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        }    
        
        return _persistentStoreCoordinator;
    }
    
    #pragma mark - Application's Documents directory
    
    // Returns the URL to the application's Documents directory.
    - (NSURL *)applicationDocumentsDirectory
    {
        return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
    }
    
    @end
    
    Thanks in advance!
     

    Attached Files:

  2. DannyBres macrumors 65816

    DannyBres

    Joined:
    Oct 30, 2007
    Location:
    UK
    #2
    I have no idea what you are trying to do.

    Assuming by list you mean a UITableView; where is the code to populate the table?

    I don't like the Core Data code in your view controller. I normally create a seperate store object to access my model for me.
     
  3. stefansaeys thread starter macrumors newbie

    Joined:
    Jul 30, 2014
    #3
    Thank you for answering.
    What I would like to accomplish is to put in a name (or multiple names) in the textfield on the startpage.
    If the database contains several names, I would like to export these names to a TXT file (or CSV file) over smb://ip_address of windows share.
    Or if that doesn’t work send the list by email.
    CoreData on the startpage works, because if I use the button “find” it does find the name that was inputted before.

    Hope this is more clear now.
     
  4. Dookieman, Aug 1, 2014
    Last edited: Aug 1, 2014

    Dookieman macrumors 6502

    Joined:
    Oct 12, 2009
    #4
    Have you considered putting your data in a plist? Using a plist to store/retrieve data is much easier to deal with than CoreData. The down side is plists don't scale well and once you have a large amount of entries it can slow the app down.

    Plists are a decent way to store data that consists of strings and numbers.
     

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