I am trying to add an object to an NSMutableDictionary using the setObject:forKey: function,
but for whatever reason, when I run my app in the iPhone simulator and try to perform the action, the code stops at the line were I am trying to add the object to the dictionary. The line where the program gets stuck is as follows:
[_dict setObject:_tf.text forKey:[NSString stringWithFormat:#"keywords_%i", [_keywordsArray count]]];
Where '_dict' is an NSMutableDictionary object, '_tf' is a UITextField, and '_keywordsArray' is an NSMutableArray.
Overall, I am using the objects (aka keys) from my dictionary to populate an NSMutableArray, which is used to fill a UIPickerView. Initially, I load the dictionary from a .plist file, and I can tell the NSMutableDictionary and the NSMutableArray are both getting populated/filled correctly, and that the UIPickerView is working fine, the only part that isn't working is adding objects to the NSMutableDictionary (when the user presses a button in the UI). Also, I did get an error once that said that the NSMutableArray had a count of 0 (zero), when clearly it didn't.
Any help/suggestions would be greatly appreciated!
Related
Update: Tidied up question and made it a bit clearer
I am getting EXC_BAD_ACCESS crashes on a NSManagedObject.
I have a Sentence managed object that I pass to a modal view (addStoryItem) like so:
addStoryItem.sentence = (Sentence*)[fetchedResultsController objectAtIndexPath:indexPath];
AddStoryItem is set to retain Sentence:
#property (retain) Sentence *sentence;
Sometimes the user needs to do something that shows another modal (on top of addStoryItem) - which doesn't affect this object, but it does take a copy of a NSMutableSet - sentence.audiosets
If I they do view this modal I get an EXC_BAD_ACCESS whenever I try to access or set the sentence object or its properties, once the user is returned to addStoryItem
There is a current managed object context & fetched results controller
everything works fine unless I show that modal view controller (which, afaik, doesn't have anything to do with the sentence object)
Zombies is on, but it doesn't tell me anything (BRAINS?)
Here's a simple summary of what goes on:
user selects row in tableview
I get object from table and set the modal's sentence property then display the modal with the fetchedResultsController
I display a string, image and set a nsset from the sentence to ui aspects of the modal
if the user needs to modify the nsset they display another modal, with a copy of the first nsset (which doesn't change or access the sentence object)
if I try to set a property in the sentence after closing the 2nd modal (or NSLOG sentence) - EXC_BAD_ACCESS.
As far as I'm concerned I own sentence. Other properties of addStoryItem are still hanging around in memory - but sentence isn't there when I try to get to it. Yes, I release sentence in addStoryItem's dealloc - but that's not being called (I have a log statement in there).
Can you help? Happy to provide more code or info. Pretty frustrated!
You are creating a new sentenceToUpDate in your didSelectRowAtIndexPath:. Surely, this reference will be forgotten as soon as you are out of that method.
Rather, you should assign the retrieved object to your retained property, like this:
self.sentence = [fetchedResultsController objectAtIndexPath:indexPath];
Now the instance should be retained as expected.
Another possible culprit is your copy of the NSSet. Try creating a new NSSet to make sure you are not effecting the entity:
NSSet *setToBePassedToModal = [[NSSet alloc]
initWithSet:entity.toManyRelationship];
I have a problem regarding the memory management when adding objects to a NSMutableArray. Weird thing is that it's all working fine for the first 8 objects I add, but when adding a 9th, the application crashes when retrieving this object.
UploadStatus *status = [[UploadStatus alloc] initWithStatus:[NSString stringWithFormat:#"%#: %d", NSLocalizedString(#"uploadPictureSucceeded", #""), pic_id]
andImageInProgress:nil
imageForSuccess:nil
imageForFailed:nil];
[self.delegate notify:status];
[status release];
This is being done on several places with different texts. But this object contains my status that I display in a UITableView.
In the notify method of the delegate I add the UploadStatus object to the NSMutableArray and I reload the UITableView that shows the objects inside that array.
The first 8 times I add a UploadStatus object to the array and reload the table, it shows correctly. But the 9th time I get the error [CFString retain]: message sent to deallocated instance 0x5c655c0. This error occurs when reloading the table in the cellForRowAtIndexPath method.
Weird thing is that it always shows that the objects inside the NSMutableArray are out of scope like in this screenshot:
Nevertheless if I fetch the item, convert it into the UploadStatus class and get the status from it, it all goes smoothly (for the first 8 objects).
Does anybody have a clue why it goes wrong after adding the 9th UploadStatus object to the NSMutableArray?
Thanks a lot for your help!
The problem is with this code:
[NSString stringWithFormat:#"%#: %d", NSLocalizedString(#"uploadPictureSucceeded", #""), pic_id]
You aren't retaining the string, so it goes away on the next execution of the run loop. You're getting lucky with the first 8. They happen to not get overwritten for some reason, or possibly some other object is retaining them. But the 9th one isn't and you finally see the results of the mistake.
You need for the UploadStatus object to retain that string (and later release it).
I note that you're directly accessing your ivars in this block of code rather than using accessors. This is almost certainly the root of your problem (it is the #1 cause of memory management problems in ObjC). Switch to accessors and most of your memory management problems will go away.
You should also go ahead and run the static analyzer (Build>Analyze). It might shed light. The problem is likely not in the above code; it's somewhere that you're storing something, most likely in an an ivar.
In a tab-based app when I switch between some tabs, I sometimes get EXC_BAD_ACCESS. It's not every time but if you flick back and forward a few times it eventually happens.
Defined in the .h:
NSUserDefaults *theData;
I've got this in viewWillAppear and viewWillDisappear:
[theData synchronize];
The line at fault gets called in a function at the viewWillAppear stage:
NSMutableArray *thisArray = [theData objectForKey:#"FriendsArray"];
I'm using NSUserDefaults to store a few dictionaries of data. This is populated by server calls, but there's no need for an internal database due to it being refreshed often. I am open to other ways of storing this data if that would be better.
I have tried a number of things like casting it (NSMutableArray *)[theData objectForKey:#"FriendsArray"]; or using arrayForKey and a number of other things with no improvement.
Any help or tips would be greatly appreciated.
NSMutableArray *thisArray = [theData objectForKey:#"FriendsArray"]; // retain
The way you try to make an array mutable is wrong. Also written like that, as suggested in the comments, you should probably retain that array.
Try init/alloc a new mutable array with objects like this :
NSMutableArray *thisArray =
[[NSMutableArray alloc] initWithArray:[theData objectForKey:#"FriendsArray"]];
Another method, -(id)initWithArray:(NSArray *)array copyItems:(BOOL)flag;, allows you to make a copy of the original objects.
Values in NSUserDefaults can not be mutable. You are trying to cast an immutable object into a mutable one. Try casting it into an NSArray, then cast that back into a mutable array. Should fix your issue.
There's no real reason for using
NSUserDefaults *theData;
Instead use this to recover a mutable array from UserDefaults:
NSMutableArray *thisArray =
[[NSUserDefaults standardUserDefaults] objectForKey:#"FriendsArray"] mutableCopy];
This gives you a RETAINED mutable array.
Note also that you only need to use synchronize when saving to UserDefaults, not when reading. You should synchronize pretty much after every save since your app can crash or be shut down by the iOS without you having a chance to synchronize.
I have a NSMutableDictionary of NSArrays stored in the AppDelegate. I need to add new NSArrays in one view controller and load the contents of the NSMutableDictionary in another view controller. I am using a shared appDelegate but for some reason the xcode hangs. Also I don't see any error in the debugger. THis is getting frustrating.
I have a pretty standard setup where I have an array in my controller that I'm binding to an NSTableView. When I add an object to this array with the UI, I add elements by copying the array to a mutable array, adding the contents, then copying it back. I saw this idiom somewhere, but I'm not really sure where, or whether this is actually a sane thing to do. I t works fine on Snow Leopard, but it crashes really badly on Leopard. GDB tells me it happens right at the marked line, where I copy the new array back.
#interface MyAppDelegate : NSObject {
NSArray * urls;
//other declarations
}
#property (nonatomic, retain) NSArray *urls;
#implementation MyAppDelegate
#synthesize urls;
- (void)addThing:(id)sender {
NSMutableArray *newUrls = [NSMutableArray arrayWithArray: [self urls]];
[newUrls addObject: newurlimadding];
[self setUrls: [NSArray arrayWithArray: newUrl]];
}
I'm pretty sure I must be doing something boneheaded here. Is there a better way to do this? Why am I crashing?
NSMutableArray *newUrls = [NSMutableArray arrayWithArray: [self urls]];
[newUrls addObject: newurlimadding];
[self setUrls: [NSArray arrayWithArray: newUrl]];
What did you create newUrls for if not to set it as the new value of urls?
Besides that, there are a couple of things you're doing wrong:
No model objects. Bindings hates this. Unless your table view exists solely to display the different parts of the URL (scheme, host, path, etc.), each in one column, you're not giving Bindings what it wants.
Pay attention to the fields in the Bindings Inspector. Note that there are two: Controller Key and Model Key Path. They're exactly what they say on their tins: The Controller Key is the key for a property of the controller, which should provide model objects. The Model Key Path is the key path for one or more properties in the model, which usually should provide value objects, such as strings and numbers.
You probably need to create a model class and make the URL a property of that class. I'd guess that you have other objects, perhaps in parallel arrays, that you can move to properties of the model class. Do that, so that you're working with Bindings instead of against it.
Not using array accessors. You're just setting the whole array at once, which is inefficient and may cause display problems (such as selection highlights disappearing). Implement and use array accessors for this array property. Accessorizer can help you here.
I actually have no idea whether this will fix your crash because you haven't told us anything about it. You should edit your question to include any exception messages or other crash-describing output, which you'll find in the Run Log/Debugger Console.
Also, since the type of urls can be mutable, you should set it to copy, not retain.
NSArray * things; - since this can be modified you better represent using NSMutableArray instead NSArray.
When ever you need to add some new element to the list just use 'addObject' and insert element to the list.
Your binding will make sure that UI is updated using KVO and KVC.
It looks like the problem was that I had NSURLs as my object type. Once I changed the object in my array to a custom-made KVC compliant object, I wasn't getting any more crashes.
Maybe NSURL isn't KVC-compliant on 10.5, but it is on 10.6?