+ (NSArray *) fetchAllContactsInContext:(NSManagedObjectContext *)a_context
{
NSFetchRequest *_request = [[NSFetchRequest alloc] init];
[_request setEntity:[NSEntityDescription entityForName:#"Contact" inManagedObjectContext:a_context]];
NSSortDescriptor *_sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"lastName" ascending:YES];
NSArray *_sortDescriptors = [[NSArray alloc] initWithObjects:_sortDescriptor, nil];
[_request setSortDescriptors:_sortDescriptors];
NSError *_fetchError=nil;
NSArray *_results = [[NSArray alloc] initWithArray:[a_context executeFetchRequest:_request error:&_fetchError]];
[_sortDescriptor release];
[_sortDescriptors release];
[_request release];
if (_fetchError){
NSLog(#"Contact - Error fetching contacts %#", [_fetchError localizedDescription]);
}
[_fetchError release];
return [_results autorelease];
}
I wanna ask, Is this function leaking memory? Actually Instruments is saying that this function is leaking hell lot of memory.
Can you please help me resolving the memory issue?
If you need to see where retains, releases and autoreleases occur for an object use instruments:
Run in instruments, in Allocations set "Record reference counts" on on (you have to stop recording to set the option). Cause the problem code to run, stop recording, search for there ivar of interest, drill down and you will be able to see where all retains, releases and autoreleases occurred.
Here is a simplifies version using ARC for iOS 4.3 and up:
+ (NSArray *) fetchAllContactsInContext:(NSManagedObjectContext *)aContext {
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:#"Contact"];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"lastName" ascending:YES];
[request setSortDescriptors:#[sortDescriptor]];
NSError *fetchError;
NSArray *results = [aContext executeFetchRequest:request error:&fetchError];
if (results == nil){
NSLog(#"Contact - Error fetching contacts %#", [fetchError localizedDescription]);
}
return results;
}
Why [_fetchError release]; is there?
And Why don't you use ARC?
Try to refactor this code into ARC.
Related
Note: This question has been completely re-organized due to so many down votes.
I am displaying a UITableViewController using NSFetchedResults with core data.
It displays fine, but when I push a new view controller and the user uses the back button to navigate back to the UITableView its crashes with that error.
I have been battling this for weeks and have not figured out why. I can tell that its likely related to memory management but I cant find it anywhere.
Update: Using Instruments-Zombies I found out that in fact it was crashing on CoreData -prepareResultsForResultsSet. See image
Here is the code from my FetchedResultsController
- (NSFetchedResultsController *)fetchedResultsController {
NSManagedObjectContext *thecontext;
thecontext = [(Logix_AppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
if (fetchedResultsController != nil) {
return fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"TimeOff" inManagedObjectContext:thecontext];
[fetchRequest setEntity:entity];
NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:#"timeOffStartDate" ascending:NO];
[fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
[fetchRequest setFetchBatchSize:20];
NSFetchedResultsController *theFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:thecontext sectionNameKeyPath: #"timeOffType" cacheName:nil];
self.fetchedResultsController = theFetchedResultsController;
fetchedResultsController.delegate = self;
[sort release];
[fetchRequest release];
[theFetchedResultsController release];
return fetchedResultsController;
}
Can you copy/paste the actual error from Xcode? And backtrace of where the crash happens, if any?
You definitely should not be autoreleaseing the object returned by +imageNamed:; that object is already autoreleased.
Your comment:
iVacationTimeApp[47892:19d03] -[CFString respondsToSelector:]: message sent to deallocated instance 0x95c9140
There is your answer. You have an overreleased object. May be the image, might be something else. Turn on Zombie detection in Instruments and run again.
My object has a private NSMutableArray items. I am using the following code to sort the objects in items in size order:
-(void)sortItems{
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"size" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSArray *sortedArray = [items sortedArrayUsingDescriptors:sortDescriptors];
NSMutableArray* newArray = [[NSMutableArray alloc] initWithArray: sortedArray];
[self setItems:newArray];
[sortDescriptor release];
}
Obviously this is a memory leak here, because every time I call sortItems, I am allocing new memory and assigning items to point to it. I've tried releasing the old memory as follows:
NSMutableArray* newArray = [[NSMutableArray alloc] initWithArray: sortedArray];
NSMutableArray* oldArray = [self items];
[self setItems:newArray];
[oldArray release];
But that gives an EXC_BAD_ACCESS error. I've read up on memory handling in objC, and I'm convinced I'm doing something fundamentally wrong here.
Any help would be greatly appreciated!
You're leaking the new array, not the old one:
NSMutableArray* newArray = [[NSMutableArray alloc] initWithArray: sortedArray];
[self setItems:newArray];
[sortDescriptor release];
[newArray release]; // <-- add this
The fundamental rule is that you must release anything that you have allocated, and you normally shouldn't care about keeping things retained for anyone (i.e. [self setItems:]), those who need something retained will do it themselves.
I would also recommend making self.items a mutable array, and using [self.items sortUsingDescriptors:sortDescriptor to sort inplace without creating a copy.
Is there a reason why you cannot release the newArray in your first example?
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"size" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSArray *sortedArray = [items sortedArrayUsingDescriptors:sortDescriptors];
NSMutableArray* newArray = [[NSMutableArray alloc] initWithArray: sortedArray];
[self setItems:newArray];
[newArray release];
[sortDescriptor release];
i need some information about memory management with NSManagedObjectContext objects.
I`m programming on an ipad-App and i work with core data objects.
My UIApplicationDelegate controls the NSManagedObjectContext:
- (NSManagedObjectContext *)managedObjectContext {
if (__managedObjectContext != nil)
{
return __managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil)
{
__managedObjectContext = [[NSManagedObjectContext alloc] init];
[__managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return __managedObjectContext;
}
I`m using instances of the ManagedObjectContext to display my Core Data Objects.
like this.
example table view controller:
CRMAppDelegate *appDelegate = (CRMAppDelegate*) [[UIApplication sharedApplication] delegate];
self.managedObjectContext = appDelegate.managedObjectContext;
// Initialize NSFetchedResultsController to retrieve data from the database.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
[fetchRequest setEntity:[NSEntityDescription entityForName:#"Contact" inManagedObjectContext:self.managedObjectContext]];
// Sort results ascending by last name, first name.
NSSortDescriptor *sortDescriptorFirstLetterLastName = [[NSSortDescriptor alloc] initWithKey:#"firstLetterOfLastName" ascending:YES];
NSSortDescriptor *sortDescriptorLastName = [[NSSortDescriptor alloc] initWithKey:#"name_last" ascending:YES];
NSSortDescriptor *sortDescriptorFirstName = [[NSSortDescriptor alloc] initWithKey:#"name_first" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptorFirstLetterLastName, sortDescriptorLastName, sortDescriptorFirstName, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
[sortDescriptors release];
[sortDescriptorFirstLetterLastName release];
[sortDescriptorFirstName release];
[sortDescriptorLastName release];
/*
if ([self.managedObjectContext countForFetchRequest:fetchRequest error:NULL] == 0) {
[self reloadContactData];
}
*/
// Create NSFetched Results controller instance.
fetchedResultsController = [[NSFetchedResultsController alloc]
initWithFetchRequest:fetchRequest
managedObjectContext:self.managedObjectContext
sectionNameKeyPath:#"firstLetterOfLastName"
cacheName:#"ContactsViewCache"];
[fetchRequest release];
self.fetchedResultsController.delegate = self;
// Load data.
NSError *error;
if (![fetchedResultsController performFetch:&error]) {
// Update to handle the error appropriately.
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
}
Is it ok to instance the NSManagedObjectContext like this? Because, the retainCount of the context is increasing til 10 while i`m testing my APP, even though i'm releasing the the context in "viewDidUnload" and "dealloc".
I`ve tried retain the context in a handler class like this:
- (NSManagedObjectContext *)getManagedObjectContext
{
NSManagedObjectContext *context = [self.managedObjectContext autorelease];
return context;
}
Whats the best way to interact with NSManagedObjectContext - objects and instances?
Thx and sry for my stuoid question :)
The value returned by retainCount is meaningless. Don't bother looking at it.
Use the Leaks instrument or heapshot analysis to determine if your app is leaking.
All examples I find on shuffling arrays are for NSMutableArrays. Copying an NSArray to an NSMutable array, shuffling, then copying back always crashes the application. Is it even possible to shuffle an NSArray?
Anything in objective-c similar to Collections.shuffle() (Java)?
Edit
static NSUInteger random_below(NSUInteger n) {
NSUInteger m = 1;
do {
m <<= 1;
} while(m < n);
NSUInteger ret;
do {
ret = random() % m;
} while(ret >= n);
return ret;
}
- (NSArray *)loadAllData{
XYZAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
NSManagedObjectContext *managedObjectContext = appDelegate.managedObjectContext;
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Quote" inManagedObjectContext:managedObjectContext];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"id" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[request setSortDescriptors:sortDescriptors];
[request setEntity: entity];
NSError *myError;
NSArray *theResults = [managedObjectContext executeFetchRequest:request error:&myError];
if (theResults == nil) {
NSLog(#"Testing: No results found");
}else {
NSLog(#"Testing: Results found.");
}
[request release];
[sortDescriptors release];
for(NSUInteger i = [theResults count]; i > 1; i--) {
NSUInteger j = random_below(i);
[theResults exchangeObjectAtIndex:i-1 withObjectAtIndex:j];
}
return theResults;
}
warning: 'NSArray' may not respond to '-exchangeObjectAtIndex:withObjectAtIndex:' which crashed the application.
error: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[_PFArray exchangeObjectAtIndex:withObjectAtIndex:]: unrecognized selector sent to instance 0x3d35a40
OK. I think I see a problem. Always look at the error message. I thought you said that you were using NSMutableArrays in this function?
NSArray *theResults = [managedObjectContext executeFetchRequest:request error:&myError];
Change that to
NSMutableArray *theResults = [[managedObjectContext executeFetchRequest:request error:&myError] mutableCopy];
Tell me if it works, and if it doesn't, I'll try and help.
Some more info:
-exchangeObjectAtIndex:withObjectAtIndex:
is a method for a NSMutableArray. You were using a NSArray, they're different classes (NSMutableArray is a subclass (and adds methods that mean you can modify it) of NSArray).
I have difficulties displaying objects coming from CoreData in a tableView.
I have 2 sorts of entities : Sample and SampleList. What is important to know is that a SampleList has an attribute sampleSet which is a set of samples (entity of Sample)
First I succeeded in displaying every SampleList. Here is viewDidLoad:
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"SampleList" inManagedObjectContext:managedObjectContext];
[request setEntity:entity];
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"lastSampleDate" ascending:NO];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
[request setSortDescriptors:sortDescriptors];
[sortDescriptor release];
[sortDescriptors release];
NSError *error;
NSMutableArray *mutableFetchResults = [[managedObjectContext executeFetchRequest:request error:&error] mutableCopy];
if (mutableFetchResults == nil) {
// Handle error
}
[self setSampleListArray:mutableFetchResults];
[mutableFetchResults release];
[request release];
Once I click on a row in my tableView, I would like to display in another UITableView every sample from the SampleList selected.
I thought that I could pass to the subview SampleList mySampleList. But then, I don't know what to do with it as it is not organized.
How can I return an ordered array of Sample (ordered by dateSample attribute for example) ?
Thank you for your time !
You can just use NSSet and NSArray methods on sampleSet to get an ordered array:
sortedArray = [[sampleSet allObjects] sortedArrayUsingSelector:#selector(compare:)];
or if you want to specify particular sort descriptors instead of the regular "compare" method:
sortedArray = [[sampleSet allObjects] sortedArrayUsingDescriptors:sortDescriptors];