I used iphones address book data in my app ,i sorted that data and arranged in UITableViewController,but now i want to make same look as of address book means sorted in GroupedStyle having initial character as heading of section .and suggestion plz
You have to implement the tableView methods that are
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
for section headers and for this this you also have to implement
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
By doing this your table data can be viewed in grouped style.
Use something like following to sort the contacts:
NSArray* tempArray = [jsonData objectForKey:#"contacts"];
NSSortDescriptor *sortDescriptor;
sortDescriptor = [[[NSSortDescriptor alloc] initWithKey:#"first_name"
ascending:YES] autorelease];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
contactsArray = [[NSArray alloc] initWithArray:[tempArray sortedArrayUsingDescriptors:sortDescriptors]];
From the use NSPredicate to pick the contacts and add them to section that you want.
Related
I'm trying to get a proper NSFetchedRequest to query the next unwatched episodes for a given TV-Show.
It should be put together in one request because I have to hand it to a NSFetchedResultsController.
My Model (CoreData):
Show
- Seasons:NSSet<Show>
Season
- Episodes:NSSet<Episode>
Episode
- first_aired:NSDate
- watched:BOOL
There should be 1 (or 0) Episode returned for every show.
I can put this together with multiple requests.
for example:
I set the NSFetchedResultsController up to fetch every show.
in - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath i iterate over every Show to get the latest episode
+(Episode *)nextAiringEpisodeForShow:(Show *)show{
NSTimeInterval timeinterval = 0.0;
NSDate *date = [NSDate dateWithTimeIntervalSince1970:timeinterval];
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:#"Episode"];
request.predicate = [NSPredicate predicateWithFormat:#"season.show = %# AND watched = false AND season.seasonNumber > 0 AND first_aired > %#",show,date];
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:#"first_aired" ascending:NO];
request.sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
return [[show.managedObjectContext executeFetchRequest:request error:nil] lastObject];
}
The problem doing it this way:
There are Shows for which one has already watched all the episodes.
These will be displayed as (null) in the UITableView and there is no way to remove them from the UITableView because the NSFetchedResultsController is set as it's dataSource.
Furthermore there is no way to sort the TableView by first_aired when doing it this way.
Or am I missing something here?!
Instead of fetching all shows in the fetched results controller, you could fetch only shows for which there is at least one unwatched episode. This should work with the following predicate (for the fetch request on "Show"):
[NSPredicate predicateWithFormat:#"SUBQUERY(seasons, $x, ANY $x.episodes.watched == FALSE).#count > 0"]
I have a PLIST file that stores issue information. At the top is an array, and within that array there are dictionaries. Within each dictionary is a string called "Date" with different dates. I then display the date values in a table view.
I am able to determine the text of the UITableview cell tapped (and therefore the date string), but how do I then access the other values within the same dictionary? If the I know that the date string is February 16, 2012, how do I get the "Download URL"? Here is a picture of my PLIST:
You should be getting the indexPath from the cell that is tapped. The indexPath.row should give you an index number that you can use to get the correct dictionary from your array of dictionaries. If you are not already keeping this array, consider doing so if it's a manageable size.
NSDictionary *selectedIssue = [myArrayOfDictionaries objectAtIndex:indexPath.row];
NSSTring *downloadURL = [selectedIssues valueForKey:#"Download URL"];
Personally, I would never rely on the date being unique or formatted in any particular way.
You can sort your array (Issue List) by the issues date before you init your TableViewController with that data and than use the NSIndexPath of the cell that was tapped.
To sort the array with the dictionaries use this snippet:
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"date" ascending:YES];
[issues sortUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];
After that you can use the indexPath like that:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *url = [[issues objectAtIndex:indexPath.row] valueForKey:#"download_url"];
}
I have a UITableView that's populated using core data & sqlite.
I'd like to have sections grouped in the UITableView based on an attribute from the database table.
e.g If i had a category field in the database table called "type", what would be the best way of sectioning that data out?
I've seen examples using arrays, but I'm getting stuck with the core data. all the data is currently displayed from the database and I'd like to section it out somehow.
thanks in advance.
If you are using an NSFetchedResultsController to fetch your results and connect them to your UI it's pretty easy. Just set the sectionNameKeyPath: parameter of the initWithFetchRequest call to NSFetchedResultsController.
In this example, which is only slightly modified from the class reference for NSFetchedResultsController I have defined a key path that will use the section named "group" as the section title. Thus, if you have rows in your database that have a group set to "Cats" and other rows with a group set to "Dogs" your resulting table view will have 2 sections - one for cats and one for dogs.
NSManagedObjectContext *context = <#Managed object context#>;
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Configure the request's entity, and optionally its predicate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"<#Sort key#>" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
[sortDescriptors release];
[sortDescriptor release];
NSFetchedResultsController *controller = [[NSFetchedResultsController alloc]
initWithFetchRequest:fetchRequest
managedObjectContext:context
sectionNameKeyPath:#"groups"
cacheName:#"<#Cache name#>"];
[fetchRequest release];
NSError *error;
BOOL success = [controller performFetch:&error];
For more information about key-paths you have to search for the key path documentation in the Xcode doc set. For simple cases though, it's just the name of an attribute of your returned objects.
I found an array to be really useful when using sections. Take a look at my example code
Sort friends (From CoreData)
NSMutableArray* unsortedFriends = [appDelegate.core.serviceManager.storageManager getFriendList];
for(ELMUser* user in unsortedFriends) {
if ([user.friendshipConfirmed boolValue]) {
if (![user.localDeleted boolValue]) {
[friendList addObject:user];
}
} else {
if (![user.localDeleted boolValue]) {
[friendListUnconfirmed addObject:user];
}
}
}
listOfItems = [[NSMutableArray alloc] init];
[listOfItems addObject:friendList];
[listOfItems addObject:friendListUnconfirmed];
Display Cell
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
NSMutableArray *subArray = [listOfItems objectAtIndex:indexPath.section];
ELMUser* user = (ELMUser*)[subArray objectAtIndex:indexPath.row];
....
I'm using Core Data for a table view, and I'd like to use the first letter of each of my results as the section header (so I can get the section index on the side). Is there a way to do this with the key path? Something like below, where I use name.firstLetter as the sectionNameKeyPath (unfortunately that doesn't work).
Do I have to grab the first letter of each result manually and create my sections like that? Is it better to put in a new property to just hold the first letter and use that as the sectionNameKeyPath?
NSFetchedResultsController *aFetchedResultsController =
[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:managedObjectContext
sectionNameKeyPath:#"name.firstLetter"
cacheName:#"Root"];
Thanks.
**EDIT: ** I'm not sure if it makes a difference, but my results are Japanese, sorted by Katakana. I want to use these Katakana as the section index.
You should just pass "name" as the sectionNameKeyPath. See this answer to the question "Core Data backed UITableView with indexing".
UPDATE
That solution only works if you only care about having the fast index title scroller. In that case, you would NOT display the section headers. See below for sample code.
Otherwise, I agree with refulgentis that a transient property is the best solution. Also, when creating the NSFetchedResultsController, the sectionNameKeyPath has this limitation:
If this key path is not the same as
that specified by the first sort
descriptor in fetchRequest, they must
generate the same relative orderings.
For example, the first sort descriptor
in fetchRequest might specify the key
for a persistent property;
sectionNameKeyPath might specify a key
for a transient property derived from
the persistent property.
Boilerplate UITableViewDataSource implementations using NSFetchedResultsController:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return [[fetchedResultsController sections] count];
}
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
return [fetchedResultsController sectionIndexTitles];
}
- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
return [fetchedResultsController sectionForSectionIndexTitle:title atIndex:index];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
return [sectionInfo numberOfObjects];
}
// Don't implement this since each "name" is its own section:
//- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
// id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
// return [sectionInfo name];
//}
UPDATE 2
For the new 'uppercaseFirstLetterOfName' transient property, add a new string attribute to the applicable entity in the model and check the "transient" box.
There are a few ways to implement the getter. If you are generating/creating subclasses, then you can add it in the subclass's implementation (.m) file.
Otherwise, you can create a category on NSManagedObject (I put this right at the top of my view controller's implementation file, but you can split it between a proper header and implementation file of its own):
#interface NSManagedObject (FirstLetter)
- (NSString *)uppercaseFirstLetterOfName;
#end
#implementation NSManagedObject (FirstLetter)
- (NSString *)uppercaseFirstLetterOfName {
[self willAccessValueForKey:#"uppercaseFirstLetterOfName"];
NSString *aString = [[self valueForKey:#"name"] uppercaseString];
// support UTF-16:
NSString *stringToReturn = [aString substringWithRange:[aString rangeOfComposedCharacterSequenceAtIndex:0]];
// OR no UTF-16 support:
//NSString *stringToReturn = [aString substringToIndex:1];
[self didAccessValueForKey:#"uppercaseFirstLetterOfName"];
return stringToReturn;
}
#end
Also, in this version, don't forget to pass 'uppercaseFirstLetterOfName' as the sectionNameKeyPath:
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext
sectionNameKeyPath:#"uppercaseFirstLetterOfName" // this key defines the sections
cacheName:#"Root"];
And, to uncomment tableView:titleForHeaderInSection: in the UITableViewDataSource implementation:
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
return [sectionInfo name];
}
There may be a more elegant way to do this, but I recently had the same problem and came up with this solution.
First, I defined a transient property on the objects I was indexing called firstLetterOfName, and wrote the getter into the .m file for the object.
e.x.
- (NSString *)uppercaseFirstLetterOfName {
[self willAccessValueForKey:#"uppercaseFirstLetterOfName"];
NSString *stringToReturn = [[self.name uppercaseString] substringToIndex:1];
[self didAccessValueForKey:#"uppercaseFirstLetterOfName"];
return stringToReturn;
}
Next, I set up my fetch request/entities to use this property.
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Object" inManagedObjectContext:dataContext];
[request setEntity:entity];
[NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"name" ascending:YES selector:#selector(caseInsensitiveCompare:)];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
[request setSortDescriptors:sortDescriptors];
Side note, apropos of nothing: Be careful with NSFetchedResultsController — it's not exactly fully baked yet IMHO, and any situation beyond the simple cases listed in the documentation, you will probably be better off doing it the 'old fashioned' way.
I solved this using the UILocalizedIndexCollation as mentioned in the NSFetchedResultsController v.s. UILocalizedIndexedCollation question
The elegant way is to do make the "firstLetter" a transient property, HOWEVER in practice that is slow.
It is slow because for a transient property to be calculated, the entire object needs to be faulted into memory. If you have a lot of records, it will be very, very slow.
The fast, but inelegant way, is to create a non-transient "firstLetter" property which you update each time you set your "name" property. Several ways to do this: override the "setName:" assessor, override "willSave", KVO.
See my answer to a similar question here, in which I describe how to create localized sectionKey indexes that are persisted (because you cannot sort on transient attributes in an NSFetchedResultsController).
Here is the simple solution for obj-c, several years and one language late . It works and works quickly in a project of mine.
First I created a category on NSString, naming the file NSString+Indexing. I wrote a method that returns the first letter of a string
#implementation NSString (Indexing)
- (NSString *)stringGroupByFirstInitial {
if (!self.length || self.length == 1)
return self;
return [self substringToIndex:1];
}
Then I used that method in the definition of the fetched result controller as follows
_fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:#"name.stringGroupByFirstInitial"
cacheName:nil];
The above code in conjunction with the two stringIndex methods will work with no need for messing about with transient properties or storing a separate attribute that just holds the first letter in core data
However when I try to do the same with Swift it throws an exception as it doesn't like having a function as part key path (or a calculated string property - I tried that too) If anyone out there knows how to achieve the same thing in Swift I would dearly like to know how.
I am trying to implement a Core Data backed UITableView that supports indexing (eg: the characters that appear down the side, and the section headers that go with them). I have no problems at all implementing this without Core Data using:
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section;
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView;
I also have no problem implementing a UITableView that is backed by Core Data without using the indexing.
What I am trying to figure out is how to elegantly combine the two? Obviously once you index and re-section content, you can no longer use the standard NSFetchedResultsController to retrieve things at a given index path. So I am storing my index letters in an NSArray and my indexed content in an NSDictionary. This all works fine for display, but I have some real headaches when it comes to adding and deleting rows, specifically how to properly implement these methods:
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller;
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath;
- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type;
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller;
Because the index paths it's returning me have no correlation with the ones in core data. I got add working by simply rebuilding my index NSArray and NSDictionary when the user adds a row, but doing the same when they delete one crashes the whole application.
Is there a simple pattern/example I'm missing here to make all this work properly?
Edit: Just to clarify I know that the NSFetchedResultsController does this out of the box, but what I want is to replicate the functionality like the Contacts app, where the index is the first letter of the first name of the person.
You should use your CoreData NSFetchedResultsController to get your sections/indexes.
You can specify the section key in the fetch request (I think it has to match the first sort key):
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]
initWithKey:#"name" // this key defines the sort
ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext
sectionNameKeyPath:#"name" // this key defines the sections
cacheName:#"Root"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
Then, you can get the section names like this:
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
return [sectionInfo name];
}
And the section indexes are here:
id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
[sectionInfo indexTitle]; // this is the index
Changes to the content just indicate that the table needs to be updated:
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {
[self.tableView reloadData];
}
UPDATE
This only works for the index and fast index scrolling, not for the section headers.
See this answer to "How to use the first character as a section name" for more information and details on how to implement first letters for section headers as well as the index.