I am making chat-app and I looking the way to save and load from core data.
I save and load to it all user's history and it works good.
I am looking the way how can I load and save roster list
I am not sure here. I load user's info from web at startup by getting user's ids from roster list and request web service for that user's info. I want to save it to core data with roster list.
How can I set for every jUser (loaded from core data) his web server info? There are 2 problems here:
I can not get JUser from core data for its id
If I do 1. I can set to that user his web image and data to his core data's storied account. - I think it is not a good idea. How can I manage users here?
Some code:
- (NSFetchedResultsController *)fetchedResultsController
{
if (_fetchedResultsController == nil)
{
NSManagedObjectContext *moc = [[self appDelegate] managedObjectContext_roster];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"XMPPUserCoreDataStorageObject"
inManagedObjectContext: moc];
NSSortDescriptor *sd1 = [[NSSortDescriptor alloc] initWithKey:#"sectionNum" ascending:YES];
NSSortDescriptor *sd2 = [[NSSortDescriptor alloc] initWithKey:#"displayName" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObjects: sd1, sd2, nil];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:entity];
[fetchRequest setSortDescriptors:sortDescriptors];
[fetchRequest setFetchBatchSize:10];
_fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:moc
sectionNameKeyPath:#"sectionNum"
cacheName:nil];
[_fetchedResultsController setDelegate:self];
NSError *error = nil;
if (![_fetchedResultsController performFetch:&error])
{
//DDLogError(#"Error performing fetch: %#", error);
}
}
return _fetchedResultsController;
}
What you are showing above is for keeping track/getting the info that is populated with a request to the XMPP server for it's roster (be it an autoFetch or a manual fetch using the XMPPRoster 'fetchRoster' method (assuming you have set the CoreData way of storing your roster data, not memory).
Once the response to the roster fetch is returned (iq result), the delegates within the XMPPRoster instance will capture and put in place with the given storage option. If the server you are using conforms to the XMPP rfc, then this should happen pretty automatically on the return.
For example - in XMPPRoster.didReceiveIQ() - you can see the call to '[xmppStorage handleRosterItem:item xmppStream:xmppStream]'. This is where the processed
You can extend the storage here (XMPPRosterCoreDataStorage and XMPPUserCoreDataStorage for example) and set in place to add additional information to the entity. For example here - XMPPUserCoreDataStorage has an over-ride '(void)didUpdateWithItem:(NSXMLElement *)item' that you can define attributes in to point to another entity. Here you would copy the existing data model and add your own attributes to it - using the over-ride above to enter them.
As for the messages, depends on if a MUC or a 1:1 - but they use different managed objects as well. XEP-0045 is what is storing the MUC messages that you can try to attach to for the users last message in there - as well as XMPPMessageArchiving for the 1:1 storage, but you would still need support from the server on this if you need to persist the capturing of another users last message - unless you are only talking about per session (which you could then store locally for display).
Related
I want to provide user a functionality to delete single or multiple messages at a time using long-tap/select action.
I know you want to know what I have tried so far. But the thing is I haven't found anything regarding deleting messages to implement.
Any kind of help is appreciated!
You have to delete message from xmpp core database.
So xmpp had created "XMPPMessageArchiving_Message_CoreDataObject" named core database table and using this you can delete message.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"XMPPMessageArchiving_Message_CoreDataObject" inManagedObjectContext:myAppdelObject.Obj_xmppManager.moc];
[fetchRequest setEntity:entity];
NSError *error;
NSArray *items = [mocObject executeFetchRequest:fetchRequest error:&error];
for (NSManagedObject *managedObject in items) {
[mocObject deleteObject:managedObject];
}
#Parthpatel1105's answer is right, though as #Bista says, it will not delete the messages permanently.
After performing the deletion, any deletion, either full deletion as #Parthpatel1105 does, or a single message, which would be the same but without the for loop and you'd have to find the single message to delete. You HAVE to save the storage context.
Which means, after doing:
for (NSManagedObject *managedObject in items) {
[mocObject deleteObject:managedObject];
}
You have to add a call to save,
In Swift (where I've used it):
mocObject.save()
In Objective-C, I think it would be something like:
[mocObject save:&error];
Having a really hard time grasping the way core data works, and I'm hoping I can get some very basic help here.
I have two entities:
Profiles<-->>Events
I have successfully figured out how to add profiles, view profiles in table view and view events for a profile in a table view via a predicate fetch.
Now, here is where I am lost. Lets say I want to update an event in the Event entity. Do I have to do a fetch with predicate to create a Profiles object before I update the Event entity? Or can I just update the Event entity and somehow tell it which Profile it is associated with via the relationship?
Here is where I have hit the log jam:
// add new event
//NSLog(#"Adding New Event");
NSManagedObjectContext *managedObjectContext = [self managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:#"Events"];
NSPredicate *predicate=[NSPredicate predicateWithFormat:#"ANY profile.profilename=[cd] %#",[self profilename]];
[fetchRequest setPredicate:predicate];
self.events = [[managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy];
//insert event info
NSManagedObject *eventInfo = [NSEntityDescription insertNewObjectForEntityForName:#"Events" inManagedObjectContext:self.managedObjectContext];
///////// THIS IS WHERE I NEED HELP
}
// save the context
NSError *error = nil;
if (![managedObjectContext save:&error]){
NSLog(#"Error! %#",error);
}
I'm about ready just to create a flat file and work with that! It's driving me nuts!
EDIT - CHANGED CODE BELOW ***********************
// add new event
//NSLog(#"Adding New Event");
Events *newEvent = (Events *)[NSEntityDescription insertNewObjectForEntityForName:#"Events" inManagedObjectContext:managedObjectContext];
newEvent.eventdesc=self.eventDescTextField.text;
NSString *wkst = eventDescTextField.text;
NSNumber *wk = [NSNumber numberWithInteger: [wkst integerValue]];
newEvent.weeksout = wk;
So now I know I need to tell the Event entity to use the current profile..how do I access the relationship?
Looking at the code you've provided, I think you have a misconception about Core Data.
It looks like you are trying to get all the events related to a profile. You don't need to create ond perform a fetch request for this. Core Data is an object graph. Which means that if you have an object in an a managed object context, you get its related objects via it's relationships, you don't need to run a fetch request.
The code below does not delete the entity. The "delete was successful" message appears on the console so the entity is found. All other operations I use succeed.
I am using RestKit 0.20.
NSManagedObjectContext *context = [RKManagedObjectStore defaultStore].mainQueueManagedObjectContext;
NSError *error = nil;
NSFetchRequest * fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity: [NSEntityDescription entityForName:#"Auction" inManagedObjectContext:context]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"AuctionID = %d", auctionID];
[fetchRequest setPredicate:predicate];
NSArray *result = [context executeFetchRequest:fetchRequest error:&error];
if(result.count) {
Auction *block = result[0];
[context deleteObject:block];
BOOL status = [context save:&error];
if (status == NO) {
NSLog(#"delete falied for AuctionID:%d, error: %#", auctionID, error);
}
else {
[context processPendingChanges];
NSLog(#"delete was successful for AuctionID:%d", auctionID);
}
}
Why might this delete operation not succeed and what is the solution to making it work.
I found this solution :
In fact, you have to fetch datas from the persistentstore and not the current created managed context :
NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:#"MyModel"];
NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:#"id" ascending:NO];
fetchRequest.sortDescriptors = #[descriptor];
// Setup fetched results
NSFetchedResultsController *fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:[RKManagedObjectStore defaultStore].persistentStoreManagedObjectContext
sectionNameKeyPath:nil
cacheName:nil];
// AND TO DELETE A MODEL :
[[RKManagedObjectStore defaultStore].persistentStoreManagedObjectContext deleteObject:myobject];
i am doing the same thing and have nearly same code.
In my code also, i get delete done and saved....
But, its not deleted when i am checking DB.
the problem is not with simulator... SURE bcz i am getting same problem on device also.
there is something called child context, it might be the cause...Check these links http://restkit.org/api/0.20.0-dev/Classes/RKManagedObjectRequestOperation.html#//api/name/managedObjectContext
RestKit 0.20 — What is the preferred way to create a new NSManagedObject?
. If you found solution pls share here
#Sumitiscreative I ran into the same issue today. What if found was that normally using Core Data you have to use
[NSManagedObject save:]
for it to store the changes. I dug through Restkit a bit and found this
[[RKManagedObjectStore defaultStore].persistentStoreManagedObjectContext deleteObject:(NSManagedObject *)];
[[RKManagedObjectStore defaultStore].persistentStoreManagedObjectContext saveToPersistantStore:(NSError *)];
Calling this after the above delete method is working to remove the object out of the DB.
**Edit - Also I would have just made this a comment but i don't have the option
#Lance
Hey, pls update your restkit with the latest version.
As now, this works in the latest version , if your server related configuration is correct. and if you get success codes for your delete request from server. Then, restkit automatically deletes the data.
If you need to delete any data externally then, you can use persistentStoreManagedObjectContext and after deleting, save it.
Also, if you want to check at your end that whether its correctly deleting via restkit or not. what you can do is ...
make delete request, after success
check with same id, if item exists. (just for help)
I am having a strange issue with MagicalRecord. Deletes will not persist. When I delete, NSFetchedResultsControllerDelegate correctly sees that the object has been deleted. However, if I close and reopen the app, the entity reappears.
The code I am using to delete the entity is:
ActivityType *activityType = [_fetchedResultsController objectAtIndexPath:indexPath];
[activityType deleteInContext:[NSManagedObjectContext MR_defaultContext]];
[[NSManagedObjectContext MR_defaultContext] MR_saveToPersistentStoreAndWait];
The code I am using for setting up the NSFetchedResultsController is:
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription
entityForName:#"ActivityType" inManagedObjectContext:[NSManagedObjectContext defaultContext]];
[fetchRequest setEntity:entity];
NSSortDescriptor *sort = [[NSSortDescriptor alloc]
initWithKey:#"name" ascending:YES];
[fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
NSFetchedResultsController *theFetchedResultsController =
[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
managedObjectContext:[NSManagedObjectContext defaultContext] sectionNameKeyPath:nil
cacheName:#"activityTypes"];
_fetchedResultsController = theFetchedResultsController;
_fetchedResultsController.delegate = self;
Based on other SO posts, I also tried to use [NSManagedObjectContext rootSavingContext] in both the setup and deletion (but to no avail).
I've been through hell and back with core data, and I learned a few things. I'm tired so I'll just write a quick summary.
When you delete an entity, core data may reject it due to your deletion rules. The reason why my deletes didn't go through is because it needed to be cascade but it was nullify. I think it has to do with somehow leaving entities abandoned. I don't know why that would be cause to prevent deletion, but that's what fixed it in my case. The way I discovered it was through log, I saw some statement about a referenced dependent entity, and I realized that delete rules will apply.
When the log says something about a serious error and a listener, check the FRC code. Since this is the listener, your culprit code will be here somewhere. In my case, I disabled [tableview beginUpdates] and [tableview endupdates]. The FRC actually needs this (I thought it was optional). Otherwise, you get some error about inconsistency and managedobjectcontextlistener and how rows need to be added or deleted etc. etc.
when you delete, it may actually get saved into the memory local context, but may not get saved to the persistent store. this means that the FRC delegate code will see the changes, but it may not get saved. also, the memory store may not do the deletion rules checks as it passed mine. but the persistent store will do the checks. gotta look into this more.
I am using Core Data on iOS and am having problems with NSFetchRequest.
If I create an NSFetchRequest like so:
NSFetchRequest* request = [ NSFetchRequest fetchRequestWithEntityName:#"Recipe"];
and then create instances of my Recipe entity, they appear in the results of the fetch request as expected. But once I save the database, and try to reload them then my fetch request returns no results.
The database saves successfully, with no errors, and using SQLite database browser I can see that all my entities have been saved in the underlying SQLite database. But they won't load...
is there an easy way to diagnose what is happening under the hood in a NSFetchRequest so I can find out why it won't load my entities?
// load recipes unsorted
NSFetchRequest* request = [ NSFetchRequest fetchRequestWithEntityName:#"Recipe"];
request.sortDescriptors = [[NSArray alloc] init];
NSFetchedResultsController* frc = [[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:self.recipeDatabase.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
// fetch results empty
NSError* error = nil;
[frc performFetch:&error];
Sorry.... I found my problem. I was not opening the UIManagedDocument when the state was UIDocumentStateClosed. Strange that everything else seems to work when operating on the documents managedObjectContext, even though the document is closed.