Displaying Coredata in UITableView

Question

I'm trying to create a UITable view to display a datasource saved through core data. I would like each row to be named after one of the attributes (in my case the name of the song). I have successfully made tables that display arrays but not saved data. I think that i need to import the list in tagsviewcontroller and put some code into the numberofrowsinsection and cellforrowatindex but I couldn't get my head around the apple doc's. Any help would be great and if you need me to post more of the code i can do that.

I am fairly new to this, i've created a Tableviewcontroller using a standard xcode template as shown below.

//  TagsViewController.h

#import <UIKit/UIKit.h>

@interface TagsViewController : UITableViewController <UITableViewDataSource, UITableViewDelegate, NSFetchedResultsControllerDelegatee>


@property (nonatomic, strong) NSManagedObjectContext *context;
@end

and the .m file

#import "TagsViewController.h"
#import "Music.h"



@interface TagsViewController ()

@property (nonatomic, strong) NSFetchedResultsController *fetchedResultsController;

@end

@implementation TagsViewController

@synthesize fetchedResultsController=_fetchedResultsController, context=_context;

- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
    // Custom initialization
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];

// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;

// Uncomment the following line to display an Edit button in the navigation bar for this     view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
}

- (void)viewWillAppear
{
    [self.tableView reloadData];
}


- (void)viewDidUnload
{
    // Release any properties that are loaded in viewDidLoad or can be recreated lazily.
    self.fetchedResultsController = nil;
}


- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[self.fetchedResultsController sections] count];
}

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
// Configure the cell to show the book's title
Music *music = [self.fetchedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text = music.name;
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
return [sectionInfo numberOfObjects];
}

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

// Configure the cell.
[self configureCell:cell atIndexPath:indexPath];
return cell;
}



/*
 Returns the fetched results controller. Creates and configures the controller if     necessary.
 */
- (NSFetchedResultsController *)fetchedResultsController
{
if (_fetchedResultsController != nil) {
    return _fetchedResultsController;
}

// Create and configure a fetch request with the Book entity.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Music" inManagedObjectContext:self.context];
[fetchRequest setEntity:entity];


// Create the sort descriptors array.
   // NSSortDescriptor *authorDescriptor = [[NSSortDescriptor alloc] initWithKey:@"author" ascending:YES];
   // NSSortDescriptor *titleDescriptor = [[NSSortDescriptor alloc] initWithKey:@"title" ascending:YES];
   // NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:authorDescriptor, titleDescriptor, nil];
   // [fetchRequest setSortDescriptors:sortDescriptors];

// Create and initialize the fetch results controller.
_fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.context sectionNameKeyPath:@"artist" cacheName:@"Root"];
_fetchedResultsController.delegate = self;

// Memory management.

return _fetchedResultsController;
}

- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
// The fetch controller is about to start sending change notifications, so prepare the table view for updates.
[self.tableView beginUpdates];
}


- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath
{
UITableView *tableView = self.tableView;

switch(type) {

    case NSFetchedResultsChangeInsert:
        [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
        break;

    case NSFetchedResultsChangeDelete:
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
        break;

    case NSFetchedResultsChangeUpdate:
        [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
        break;

    case NSFetchedResultsChangeMove:
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
        [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
        break;
}
}

- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
switch(type) {

    case NSFetchedResultsChangeInsert:
        [self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
        break;

    case NSFetchedResultsChangeDelete:
        [self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
        break;
}
}


- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
// The fetch controller has sent all current change notifications, so tell the table view to process all updates.
[self.tableView endUpdates];
}

I know that i'll have to import certain files. My database is called music.xcmodeld and has its own music.h and m file.

 #import <Foundation/Foundation.h>
 #import <CoreData/CoreData.h>


  @interface Music : NSManagedObject

 @property (nonatomic, retain) NSString * name;
 @property (nonatomic, retain) NSString * artist;
 @property (nonatomic, retain) NSString * album;

 @end

with .m file

 #import "Music.h"


 @implementation Music

 @dynamic name;
 @dynamic artist;
 @dynamic album;

 @end

Answer 1

- (void)viewDidLoad
 {
[super viewDidLoad];

arrData = [[NSMutabaleArray alloc]init];

NSManagedObjectContext *context = //Get it from AppDelegate

NSFetchRequest *request = [[NSFetchRequest alloc]initWithEntityName:@"Music"];

NSError *error = nil;

arrData = [[context executeFetchRequest:request error:&error]mutablecopy];

if (error != nil) {

   //Deal with failure
}
else {

   //Deal with success
}
 // Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;

// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
 }

For Table View

#pragma mark - Table view data source

 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
 {
     return 1;
 }

 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {
     return arrData.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] autorelease];
}
Music *obj = [arrData objectAtindex:indexPath.row];
cell.textLabel.text = obj. name;
// Configure the cell...

return cell;
 }

Answer 2

you can use NSFetchedResultsController a sample code is here

http://developer.apple.com/library/ios/#samplecode/CoreDataBooks/Listings/Classes_RootViewController_m.html#//apple_ref/doc/uid/DTS40008405-Classes_RootViewController_m-DontLinkElementID_14

Answer 3

There is no difference if you display from array or core data. Just query core data when the view controller is loading and add the results to an array. Then you know what to do with an array of data.

In cell for row at index you would pull each object from the array and add whatever you want from it to the cell