I'm going a little mad I think. This is the VERY first thing I do and I get the crash (seen below). The crash is the moment I try to step over the executeFetchRequest.
If I remove request.sortDescriptors= sortDescriptors it works.
I must be doing something insanely stupid. But even after walking away a couple times, I still can't see it. index is a non-optional Integer32, with default of 1.
- (void)awakeFromNib {
[self defaultData];
}
- (void)defaultData {
NSManagedObjectContext* moc= self.managedObjectContext; // all code with this
[NSEntityDescription insertNewObjectForEntityForName:#"Envelope"
inManagedObjectContext:moc];
NSFetchRequest* request = [NSFetchRequest
fetchRequestWithEntityName:#"Envelope"];
NSArray* sortDescriptors= [NSArray arrayWithObject:#"index"];
request.sortDescriptors= sortDescriptors;
NSError* error = nil;
NSArray* results = [moc executeFetchRequest:request error:&error];
}
And here's my crash:
-[__NSCFConstantString key]: unrecognized selector sent to instance 0x240f4
Tried deleting the 'iPhone Simulator' folder. Tried deleting and recreating the xcdatamodeld. Perhaps a leak in my nib files (though can't see anything). Tried gcc (currently Apple LLVM 3.1). I've tried moving everything over to a new project. I've tried starting a project completely fresh. I've tried saving the context before doing the fetch.
I already know I'm going to hate the answer. It's going to be stupid, I'm going to feel foolish, but I need another set of eyes.
Thanks
Greg
sortDescriptors is supposed to be an array of NSSortDescriptor; your sortDescriptors just has #"index" (an NSString). Try this:
NSArray* sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:#"index" ascending:NO]];
request.sortDescriptors = sortDescriptors;
Related
I've been working on adding icloud to my project (which is quite a pain in the buns) and I'm able to save and remove files, but I can't get a list of the files stored in iCloud. I've tried solutions from about 10 different websites (including the Apple documentation). Whenever I call [self.query startQuery]; everything seems to be working: The correct methods get called, the methods execute exactly as they should. Then when I ask for an nsarray of the files in my app's iCloud Documents directory I get two parenthesis with nothing between them (when I view in NSLog): File List: ( ). I know for a fact that there are many different documents of all shapes, extensions, sizes, and names in my app's iCloud Documents directory because I've been using the iCloud Developer site to check if things are working. My first method to setup the query is as follows:
- (void)syncWithCloud {
self.query = [[NSMetadataQuery alloc] init];
NSURL *mobileDocumentsDirectoryURL = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];
[query setSearchScopes:[NSArray arrayWithObjects:NSMetadataQueryUbiquitousDocumentsScope, nil]];
//[query setPredicate:[NSPredicate predicateWithFormat:#"%K LIKE '*'", NSMetadataItemFSNameKey]];
[query setPredicate:[NSPredicate predicateWithFormat:[NSString stringWithFormat:#"%%K like \"%#*\"", [mobileDocumentsDirectoryURL path]], NSMetadataItemPathKey]];
//Pull a list of all the Documents in The Cloud
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(processFiles:)
name:NSMetadataQueryDidFinishGatheringNotification object:self.query];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(processFiles:)
name:NSMetadataQueryDidUpdateNotification object:self.query];
[self.query startQuery];
}
The process files method provided by Apple is next:
- (void)processFiles:(NSNotification*)aNotification {
NSMutableArray *discoveredFiles = [NSMutableArray array];
//Always disable updates while processing results.
[query disableUpdates];
//The query reports all files found, every time.
NSArray *queryResults = [query results];
for (NSMetadataItem *result in queryResults) {
NSURL *fileURL = [result valueForAttribute:NSMetadataItemURLKey];
NSNumber *aBool = nil;
// Don't include hidden files.
[fileURL getResourceValue:&aBool forKey:NSURLIsHiddenKey error:nil];
if (aBool && ![aBool boolValue])
[discoveredFiles addObject:fileURL];
}
//Update the list of documents.
[FileList removeAllObjects];
[FileList addObjectsFromArray:discoveredFiles];
//[self.tableView reloadData];
//Reenable query updates.
[query enableUpdates];
NSLog(#"File List: %#", FileList);
}
Why doesn't this give me a list of files or at least some kind of data? Am I defining the NSMetadata query wrong, maybe my predicate isn't formatted right? I know I'm doing something wrong because there's no way iCloud could be this complicated (or could it?).
Thanks for the help in advance!
Edit #1: I am continuing to try different approaches to this problem. Using one of the answers below I have changed the predicate filter as follows:
[query setPredicate:[NSPredicate predicateWithFormat:#"NSMetadataItemFSNameKey LIKE '*'"]];
I have also added the following lines before the [query enableUpdates] call:
for (NSMetadataItem *item in query.results) {
[FileList addObject:[item valueForAttribute:NSMetadataItemFSNameKey]];
}
In the processFiles method, I've tried placing all of the code on the background thread, but this makes no difference - as a matter of fact, when the code is not executed on the background thread FileList gives me this (null) instead of this ( ).
Could my problem have to do with thread management or memory allocation? Please note that I am using ARC.
Edit #2: The FileList variable is an NSMutableArray defined in my #interface and initialized in the -(id)init method before calling the processFiles method.
Edit #3: When testing my code with breakpoints I found that the following for-loop never gets run through - not even once. This leads me to believe that:
A. The proper directory isn't being connected with
B. iCloud can't see the files in the directory
C. My NSMetadataQuery isn't being setup properly
D. Something completely different
Here's the code that starts the for-loop which never gets run:
NSArray *queryResults = [query results];
for (NSMetadataItem *result in queryResults) {
Since you already set the search scope correct, there's no need to use special filters in the predicate.
Just use:
query.predicate = [NSPredicate predicateWithFormat:#"NSMetadataItemFSNameKey == '*'"];
And to get the array use:
NSMutableArray *array = [NSMutableArray array];
for (NSMetadataItem *item in query.results) {
[array addObject:[item valueForAttribute:NSMetadataItemFSNameKey]];
}
I've solved my problem. Getting the list of files in iCloud was just a matter of correctly defining, allocating, and initializing properties. SAE's answer and this SO posting helped me solve my problem and create this GitHub Repo called iCloud Document Sync. The iCloud Document Sync class simplifies the whole iCloud Document storage process down to a few lines of code. The commit linked here fixes the issues from my question.
I am using Core Data to store some information for my app.
I have a .xcdatamodeld file containing 8 entities, and I extract them on different views.
In one of the viewControllers, I call three of them. Like this:
AppDelegate *appDelegate = (AppDelegate *) [[UIApplication sharedApplication]delegate];
managedObjectContext = appDelegate.managedObjectContext;
NSManagedObjectContext *moc = [self managedObjectContext];
NSEntityDescription *entiAll = [NSEntityDescription entityForName:#"AllWeapons" inManagedObjectContext:moc];
NSFetchRequest *frAll = [[NSFetchRequest alloc] init];
[frAll setEntity:entiAll];
NSError *error = nil;
arrAll = [moc executeFetchRequest:frAll error:&error];
displayArray = [[NSMutableArray alloc]initWithArray:arrAll];
NSEntityDescription *entiRange = [NSEntityDescription entityForName:#"WeaponsRanged" inManagedObjectContext:moc];
NSFetchRequest *frRanged = [[NSFetchRequest alloc] init];
[frRanged setEntity:entiRange];
NSError *errorRanged = nil;
arrRange = [moc executeFetchRequest:frRanged error:&errorRanged];
NSLog(#"%i, %i", [arrRange count], [[moc executeFetchRequest:frRanged error:&errorRanged] count]);
NSEntityDescription *entiMelee = [NSEntityDescription entityForName:#"WeaponsMelee" inManagedObjectContext:moc];
NSFetchRequest *frMelee = [[NSFetchRequest alloc] init];
[frMelee setEntity:entiMelee];
NSError *errorMelee = nil;
arrMelee = [moc executeFetchRequest:frMelee error:&errorMelee];
NSLog(#"%i, %i", [arrMelee count], [[moc executeFetchRequest:frMelee error:&errorMelee] count]);
The problem is that the middle one (the one filling the arrRange-array) doesn't work..
arrAll logs out with all correct data, arrMelee logs out with all the correct data (x4 for some reason, don't know if this is related :S), but arrRange logs out as an empty array.
[arrRange count]; gives me 0, even though I know there is lots of data there.
I ran this code on the simulator, and found the .sqlite file, opened it in Firefox's SQLite Manager, and saw the correct data, 40 rows.
I went into the appDelegate, where I fill the CoreData when necessary, and saw that the method which downloads the data in JSON-format successfully sends it to the sqlite aswell.
Here I fill the CoreData with data from the json:
[self deleteAllObjects:#"WeaponsRanged"];
NSManagedObjectContext *context = [self managedObjectContext];
for(NSDictionary *item in jsonWeaponRanged)
{
WeaponsRanged *wr = [NSEntityDescription insertNewObjectForEntityForName:#"WeaponsRanged"
inManagedObjectContext:context];
///***///
wr.recoil = [item objectForKey:#"Recoil"];
///***///
NSError *error;
if(![context save:&error])
NSLog(#"%#", [error localizedDescription]);
}
And if I here do NSLog(#"%# - %#", wr.recoil, [item objectForKey:#"Recoil"]); I get the correct data. (Same data on both)
So. The correct data is obviously in the core. But my NSFetchRequest or something is failing. I am pretty noob at Objective-C, so it might be my bad code-grammar striking again. I realize I should use things again etc, not creating new objects all the time.. But cmon, this is my first app.. And if that is actually the problem, I might learn. But I'm stuck.
SOMETIMES I get data, sometimes I don't. It's weird. I re-launched the app, and got data from it, and now I don't.. I haven't found a pattern yet..
Anyone?
Or is there another way to request data from the entity?
I have some suggestions, too big for a comment.
1) after you create the WeaponsRanged, try reading them back:
for(NSDictionary *item in jsonWeaponRanged)
{
WeaponsRanged *wr = [NSEntityDescription insertNewObjectForEntityForName:#"WeaponsRanged"
inManagedObjectContext:context];
NSLog(#"IS WR Realized? %#", wr ? #"YES" : #"NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO WR");
///***///
wr.recoil = [item objectForKey:#"Recoil"];
///***///
NSError *error;
if(![context save:&error])
NSLog(#"%#", [error localizedDescription]);
}
// Now lets see if we can retrieve them:
{
NSEntityDescription *entiRange = [NSEntityDescription entityForName:#"WeaponsRanged" inManagedObjectContext:context];
NSFetchRequest *frRanged = [[NSFetchRequest alloc] init];
[frRanged setEntity:entiRange];
NSError *errorRanged = nil;
arrRange = [context executeFetchRequest:frRanged error:&errorRanged];
NSLog(#"Wrote %i items, read back %i items", [jsonWeaponRanged count], [arrRange count] );
}
2) In the viewController reading WeaponsRanged, add an assert before the fetch on mod:
NSLog(#"IS moc set? %#", moc ? #"YES" : #"NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO MOC");
EDIT:
3) Spread statements everywhere you access the MOC:
assert([NSThread isMainThread]);
[If you haven't used asserts before google and read up on the topic. These are a powerful tool for developers to find out about potential problems way before they manifest themselves in the gui or elsewhere. They are normally compiled out for release/distribution builds.]
This will force an exception if the thread is not the main thread, and then let you track down the reason by following the stack trace.
Nevermind! It was my own damn fault (yet again..).
The problem occured before the code I presented, and it turns out the data was never in the .sqlite-file when the problem was present.
This is what I had:
I collected data from the internet through json-request. I have told the app to check the "version" of the data through the internet, and if the data is outdated, then re-download it.
First, I download all data, then I add them to their own entity in Core Data. After downloading, I clear the current Core Data entity of the downloaded data. So on the top of each add-method it said i.e [self deleteAllObjectsOfEntity:#"WeaponsRanged"];, My whole problem was that in the addMelee-method, it ALSO said [self deleteAllObjectsOfEntity:#"WeaponsRanged"]; instead of #"WeaponsMelee", thus deleting all ranged weapons, and later adding melee to the melee entity. And that also proves that the other problem I mentioned of arrMelee logging out four times as much data as it should was caused by this.
The reason it sometimes worked was that the downloading is not happening in any ordered mode. So the addRanged was sometimes called before the addMelee. If ranged comes first, it clears the arrRanged, and fills it up with correct data, and THEN melee comes, and clears it out. When melee was called first, it cleared arrRanged and filled additional data to arrMelee, and THEN ranged comes and tries to clear an empty entity, and then fills it up with correct data.
The solution was obviously to change the entity deleted when adding it, as it was the wrong one.
Sorry.... :)
I have a very sporadic bug with a Core Data query containing fetchLimit and fetchOffset. Once in a long while (I've seen it happen once, as has another tester), the fetchOffset seems to be ignored. The query looks like this:
NSFetchRequest *fetch = [[NSFetchRequest alloc] initWithEntityName:#"MyEntity"];
NSSortDescriptor *dateDescriptor = [[NSSortDescriptor alloc] initWithKey:#"timestamp" ascending:NO];
NSArray *sortDescriptors = [NSArray arrayWithObject:dateDescriptor];
[fetch setSortDescriptors:sortDescriptors];
fetch.fetchOffset = 500;
fetch.fetchLimit = 1;
NSError *error = nil;
NSArray *objects = [self.managedObjectContext executeFetchRequest:fetch error:&error];
if (objects.count) {
MyEntity *objectAtLimit = [objects objectAtIndex:0];
}
This almost always returns the 501st object as desired, but on those two occasions where it broke it returned the first object.
The query is never run unless there are >500 rows in the database. I'm using iOS5. The managedObjectContext has a mainQueueConcurrencyType.
It seems to be the same behavior as reported in this question: Paging results from Core Data requests, which was never resolved (or at least not on list.) In that case the fetchOffset appeared to be either ignored or respected based on the data model being tested against.
I'm probably going to rewrite the query without the fetchOffset, just in case that is the problem, since the performance shouldn't be an issue. But I'm wondering if anyone has thoughts about where the bug might be here.
Ran across a similar problem this morning and noticed if my NSManagedObjectContext has unsaved changes that the fetchOffset may be ignored for whatever reason. After saving the context the fetchOffset is interpreted correctly.
The problem indeed seems the be connected with unsaved changes in the NSManagedObjectContext. If you set the includesPendingChanges property to false the NSFetchRequest with limit + offset will work as expected.
fetchRequest.includesPendingChanges = false
Cheers,
I'm experiencing a problem with core data, I guess I'm just looking in the wrong direction again.
My managedObjectContext will return an empty NSSet if I call registeredObjects on it. If I execute a fetch beforehand however, it will return the same objects that as the fetch did just a moment ago.
There's no multithreading going on.
Here's what I do:
[self setupContext]; // This will set up managedObjectContext, which is a property of this class
// Fetching...
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *foo = [NSEntityDescription entityForName:#"Foo" inManagedObjectContext:managedObjectContext];
[request setEntity:foo];
NSError *fetchError = nil;
NSArray *fetchResults = [managedObjectContext executeFetchRequest:request error:&ftchError];
NSLog(#"Fetch returned %i objects.", [fetchResults count]);
[request release];
// Done fetching...
NSArray *allObjects = [[managedObjectContext registeredObjects] allObjects];
NSLog(#"Context contains %i objects...", [allObjects count]);
The store contains 30 objects. If I run the code above, both NSLogs will report five objects. If I remove the fetch part between the two comments, it will report zero objects for the whole context.
Note that I am at no point commiting or otherwise changing the contexts contents.
Do I need to force the context into refreshing itself first? I've never done this before though and I don't recall registeredObjects failing on me like this on other occasions in the first place.
Any suggestions appreciated!
Toastor
You may be confused about what registeredObjects means. This is the set of objects that are currently in the NSManagedObjectContext. This is not the set of objects in the store, just the ones in the context. If you haven't fetched or otherwise registered the objects in the context, then they won't be in registeredObjects.
So I've got an NSFetchedResultsController that I activate on ViewDidLoad with the managedobjectcontext that has been passed on from the appdelegate on load.
I put a predicate on some field let's call it "sectionNumber" and say it needs to equal 1 in my predicate.
NSFetchResultsController works fine until I add a new object to the MOContext...
I use MyMO *newObj = [NSEntityDescription insertnewentity]...
start filling the different fields
[newobj setName:#"me"];
[newobj setAge:12];
etc...
Once I put [newobj setSectionNumber:1] - it finds it at that very instant and causes the app to crash with different weird errors that all lead to EXC_BAD_ACCESS.
All of this happens on the MAIN THREAD.
Any ideas why? How could one get around that?
UPDATE:
It only happens when I use my saveMOC method which is called at the end of an NSXMLParser specific thread I spawned off. The saveMOC is called on a successful parse with the [self performSelectorOnMainThread].... If i just added the extra managedobject via ViewDidLoad (just to check weather this is related somehow to to threading) the problem does NOT occur.
So it's obviously something with the new thread even tho the selector should have been run on the main thread.
UPDATE #2:
This is my spawned thread for the XML Parser:
-(void)getAndParseXML {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
DLog(#"Online storage");
NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:theUrl];
XMLTranslator *translator = [[XMLTranslator alloc] init];
[parser setDelegate:translator];
if ([parser parse]) {
//success call MOC change routine on main thread
DLog(#"success parsing");
[self performSelectorOnMainThread:#selector(saveMOC:) withObject:translator waitUntilDone:NO];
} else {
DLog(#"error: %#",[parser parserError]);
}
[parser setDelegate:nil];
[parser release];
DLog(#"XML parsing completed");
[pool release];
}
Then this is my saveMOC:
-(void)saveMOC:(XMLTranslator*)translator {
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
for (NSDictionary *dict in [translator retrievedData]) {
APost *newPost = [NSEntityDescription insertNewObjectForEntityForName:#"APost"
inManagedObjectContext:managedObjectContext];
//parse time into NSDate
[newPost setTime:[formatter dateFromString:[dict objectForKey:#"time"]]];
//author, category, description
[newPost setAuthor:[dict objectForKey:#"author"]];
[newPost setCategory:[dict objectForKey:#"category"]];
[newPost setContent:[dict objectForKey:#"description"]];
//create a post id so that the validation will be alright
[newPost setPostid:[NSNumber numberWithInteger:[[dict objectForKey:#"postid"] integerValue]]];
[newPost setSectionDesignator:sectionDesignator];
}
This saveMoc method continues and has a [managedobjectcontext save:&error] and more... but it's not relevan to our case as my method crashes I've discovered thru commenting one line after another at the point where I set the sectionDesignator since it equals to the current predicate in my NSFetchedResultsController.
The problem is most likely in the NSFetchedResultsController delegate methods or the lack thereof.
When you add a new object to any context and then save the context, that changes the persistent store which triggers the FRC on any thread to begin an update of the tableview. All the index paths change, especially if you set a value for an attribute used as a sectionNameKeyPath. If the table ask for a cell during the update, it will cause a crash because the table can ask for a cell at a index path rendered invalid by the insertion of the new managed object.
You need to make sure you implement the FRC's delegate methods and that you send the table a beginUpdate message to freeze it while the FRC changes all its index paths.
I am sorry to admit that the problem this whole time was releasing an array that held the sort descriptors in the fetch request that was used within the FRC.
Looking at alot of examples I released that array tho unlike the examples I created my array with [NSArray arrayWithObject:.............];
So there was an overrelease each time the fetch request was accessed more than once.
Feel free to close this. Thank you everybody for your help. I discovered this when peter wrote to look at the whole stack and not just one frame.
I have further analyzed the problem and have realized it occurs inside the loop.
I have further understood that it only happens when I have more than one object, meaning that one FRC takes over after an object insertion into MOC and tries to come back to the for loop, it tries to access an object or a reference that's not there. I haven't found what object causes it and how to retain it properly.
Any suggestions?
Consider the following:
for (int i=0; i<2; i++) {
NSLog(#"%i",i);
APost *thePost = [NSEntityDescription insertNewObjectForEntityForName:#"HWBPost" inManagedObjectContext:managedObjectContext];
[thePost setCategory:#"CAAA"];
[thePost setContent:#"SSSSSS"];
[thePost setSectionDesignator:sectionDesignator];
}
If I change the for loop to i<1 meaning it only runs once, the app does NOT crash. As soon as it is more than one object insertion the app crashes.