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  • Core Data passing context between methods on secondary threads

    - by JK
    My app spawns a secondary thread for some core data store maintenance. In the secondary thread, I set up a context which I then pass to other methods e.g. [self editEntriesInContext:context]. However, this causes objects fetched from the context to become invalidated in editEntries... Why does this occur? I thought the only requirements were for the secondary thread to have its own context and managed objects, which I adhere to. (Note: The context is properly retained)

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  • Core Data multi-threading

    - by JK
    My app starts by presenting a tableview whose datasource is a Core Data SQLite store. When the app starts, a secondary thread with its own store controller and context is created to obtain updates from the web for data in the store. However, any resulting changes to the store are not notified to the fetchedresults controller (I presume because it has its own coordinator) and consequently the table is not updated with store changes. What would be the most efficient way to refresh the context on the main thread? I am considering tracking the objectIDs of any objects changed on the secondary thread, sending those to the main thread when the secondary thread completes and invoking "[context refreshObject:....] Any help would be greatly appreciated.

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  • UITextView inside UIScrollView is not First Responder

    - by Sheehan Alam
    I have a UITextView on a View that becomes the first responder. When I embed the UITextView inside of a UIScrollView in Interface Builder the UITextView is no longer the first responder. I am not sure what has changed? - (void)viewDidLoad { [super viewDidLoad]; [scrollView setContentSize:CGSizeMake(540,620)]; composeTextView.delegate = self; [composeTextView becomeFirstResponder]; }

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  • What are the correct bindings for an NSComboBox for use with Core Data

    - by theMikeSwan
    Imagine if you will a Core Data app with two entities (Employee, and Department). Employees have a to-one relationship with department (department) and the inverse is a to-many relationship (employees). In the UI you can select individual Employee entities and edit the details in a detail area (there are of course other attributes and there is UI for adding and editing Department entities). When using a popup button the bindings are: content = PopUpArrayController.arrangedObjects content values = PopUpArrayController.arrangedObjects.name (name is an NSString) selected object = EmployeeArrayController.selection.department.name This allows for viewing of all departments in the popup menu, correct selection of the current Employee's department, and allows that department to be changed as expected. The goal is to change this for an NSComboBox so that the user can tab to the box and type the department name in without switching to the mouse. I have tried numerous different bindings to accomplish this. I even had it work for one run with these bindings: content = PopUpArrayController.arrangedObjects.name value = EmployeeArrayController.selection.department.name At least once this worked as expected (it even added a new department when the entered text did not match any existing department). Now however it will display the available Departments and auto complete but will not update the model with the correct value when the value is changed in the combo box. If the Department is set or changed with the popup the correct department is shown in the combo box. Does anyone know what I am missing? Thanks.

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  • Regex solution for Objective-C

    - by rjstelling
    What is the best method for using Regular Expressions within Objective-C? There seems to be some open source project that provide regex support, can any one recommend one? Also I looked at NSPredicate, can anyone suggest any regex examples? Background: I want use regex mainly for validation, IP's, email addresses, internal ID's etc

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  • Core data many-to-many relationship - Predicate question

    - by Garry
    In my Core Data model I have two entities: List and Patient. List has an attribute called 'name'. A List can have any number of Patients and each Patient can belong to any number of different lists. I have therefore set a relationship on List called 'patients' that has an inverse to-many relationship to Patient AND a relationship on Patient called 'lists' that has a to-many relationship to List. What I'm struggling to figure out is how to create a Predicate that will select all Patients that belong to a particular List name. How would I go about this? I have never used relationships before in Core Data. Thanks,

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  • NSString's stringByAppendingPathComponent: removes a '/' in http://

    - by Jasarien
    I've been modifying some code to work between Mac OS X and iPhone OS. I came across some code that was using NSURL's URLByAppendingPathComponent: (added in 10.6), which as some may know, isn't available in the iPhone SDK. My solution to make this code work between OS's is to use NSString *urlString = [myURL absoluteString]; urlString = [urlString stringByAppendingPathComponent:@"helloworld"]; myURL = [NSURL urlWithString:urlString]; The problem with this is that NSString's stringByAppendingPathComponent: seems to remove one of the /'s from the http:// part of the URL. Is this intended behaviour or a bug? Edit Ok, So I was a bit too quick in asking the question above. I re-read the documentation and it does say: Note that this method only works with file paths (not, for example, string representations of URLs) However, it doesn't give any pointers in the right direction for what to do if you need to append a path component to a URL on the iPhone... I could always just do it manually, adding a /if necessary and the extra string, but I was looking to keep it as close to the original Mac OS X code as possible...

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  • Object created in Interface Builder getting dealloc'ed too soon

    - by Collin Allen
    The Project I'm working on a relatively simple iPhone OS project that's navigation controller based, with a root table view and a detail table view. Tap an item in the main list to see its details in a pushed table view. The Setup I broke out the data source for both views into their own objects so as not to muddy the purpose of a view controller. Having done this, the table views no longer have data sources since those methods are now in separate files, so I created an instance of each data source class in the appropriate XIB files with the Object item (dragged it in, then set its class). Then, to actually connect the tableviews to their data sources, I set the dataSource outlet of each tableview to the yellow data source object in Interface Builder. The table view delegates are still set to their view controllers. The Problem The root table view works just fine, but when you tap a row to push to the detail view, the data source object gets instantiated as expected, then immediately dealloc'ed, causing a crash (numberOfSectionsInTableView: gets called on the freed object). I can't figure out why the data source is getting automatically dealloc-ed when I need it right then and there for the detail view, as indicated by my data source object creation and tableview connection in Interface Builder. What's more perplexing is that the very approach works fine for the root tableview! The Question Is there anything obvious I'm missing that would cause this to happen? Or, is this even the right way to instantiate a data source for a table view controller? It seems like poor object oriented programming to do it from within the view controller, which should only be concerned with the view. I could cram everything in two table view controller classes and it would probably work, but it would not be as modular as I'd like. Thanks!

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  • Can I use an NSDecimalNumber anywhere that an NSNumber is expected?

    - by Nick Forge
    NSDecimalNumber is a subclass of NSNumber, and from what I can tell, it implements all of the NSNumber methods as expected for an NSNumber instance. Given that, is it ok to give NSDecimalNumbers to any code that is expecting an NSNumber? The only possible issue might be code that checks that an argument is an instance of NSNumber, but since NSNumber is a class-cluster, code like this would have to check that the instance is a subclass of NSNumber, and NSDecimalNumber instances should pass the same tests.

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  • How to detect if certain characters are at the end of an NSString?

    - by Sheehan Alam
    Let's assume I can have the following strings: "hey @john..." "@john, hello" "@john(hello)" I am tokenizing the string to get every word separated by a space: [myString componentsSeparatedByString:@" "]; My array of tokens now contain: @john... @john, @john(hello) For these cases. How can I make sure only @john is tokenized, while retaining the trailing characters: ... , (hello) Note: I would like to be able to handle all cases of characters at the end of a string. The above are just 3 examples.

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  • Confused about copying Arrays in Objective-C

    - by Sheehan Alam
    Lets say I have an array X that contains [A,B,C,D,nil]; and I have a second array Y that contains [E,F,G,H,I,J,nil]; If I execute the following: //Append y to x [x addObjectsFromArray:y]; //Empty y and copy x [y removeAllObjects]; y = [x mutableCopy]; What is the value of y? is it?: [A,B,C,D,E,F,G,H,I,J,nil] Am I performing the copy correctly?

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  • How do I copy or move an NSManagedObject from one context to another?

    - by Aeonaut
    I have what I assume is a fairly standard setup, with one scratchpad MOC which is never saved (containing a bunch of objects downloaded from the web) and another permanent MOC which persists objects. When the user selects an object from scratchMOC to add to her library, I want to either 1) remove the object from scratchMOC and insert into permanentMOC, or 2) copy the object into permanentMOC. The Core Data FAQ says I can copy an object like this: NSManagedObjectID *objectID = [managedObject objectID]; NSManagedObject *copy = [context2 objectWithID:objectID]; (In this case, context2 would be permanentMOC.) However, when I do this, the copied object is faulted; the data is initially unresolved. When it does get resolved, later, all of the values are nil; none of the data (attributes or relationships) from the original managedObject are actually copied or referenced. Therefore I can't see any difference between using this objectWithID: method and just inserting an entirely new object into permanentMOC using insertNewObjectForEntityForName:. I realize I can create a new object in permanentMOC and manually copy each key-value pair from the old object, but I'm not very happy with that solution. (I have a number of different managed objects for which I have this problem, so I don't want to have to write and update copy: methods for all of them as I continue developing.) Is there a better way?

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  • Design pattern to keep track UITableView rows correspondance to underlying data in constant time.

    - by DenNukem
    When my model changes I want to animate changes in UITableView by inserting/deleting rows. For that I need to know the ordinal of the given row (so I can construct NSIndexPath), which I find hard to do in better-than-linear time. For example, consider that I have a list of addressbook entries which are manualy sorted by the user, i.e. there is no ordering "key" that represents the sort order. There is also a corresponding UITableView that shows one row per addressbook entry. When UITableView queries the datasource I query the NSMUtableArray populated with my entries and return required data in constant time for each row. However, if there is a change in underlying model I am getting a notification "Joe Smith, id#123 has been removed". Now I have a dilemma. A naive approach would be to scan the array, determine the index at which Joe Smith is and then ask UITableView to remove that precise row from the view, also removing it form the array. However, the scan will take linear time to finish. Now I could have an NSDictionary which allows me to find Joe Smith in constant time, but that doesn't do me a lot of good because I still need to find his ordinal index within the array in order to instruct UITableView to remove that row, which is again a linear search. I could further decide to store each object's ordinal inside the object itself to make it constant, but it will become outdated after first such update as all subsequent index values will have changed due to removal of an object. So what is the correct design pattern to accurately reflect model changes in the UITableView in costant (or at least logarithmic) time?

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  • Object allocate and init in Objective C

    - by Ronnie Liew
    What is the difference between the following 2 ways to allocate and init an object? AController *tempAController = [[AController alloc] init]; self.aController = tempAController; [tempAController release]; and self.aController= [[AController alloc] init]; Most of the apple example use the first method. Why would you allocate, init and object and then release immediately?

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  • UITableViewCell is 1px shorter in didSelectRowAtIndexPath than cellForRowAtIndexPath

    - by Calvin L
    I have a UITableViewCell that I create in tableView:cellForRowAtIndexPath:. In that method I call: UITableViewCell *cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:nil] autorelease]; NSLog(@"Cell height: %f", cell.contentView.frame.size.height); This gives me a return value of 44.000000. Then in my tableView:didSelectRowAtIndexPath: method, I call: UITableViewCell *cell = [tableView cellForRowAtIndexPath: indexPath]; NSLog(@"Cell height: %f", cell.contentView.frame.size.height); And this gives me a return value of 43.000000. Aren't they the same cell? What gives?

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  • Displaying an NSString on a Custom View

    - by ilovetacos
    I have an interface that has an NSTextField, NSButton, and an NSView. When I type something in the textfield and press the button, I want the text to be drawn in the NSView. So far I have everything connected and working, except for the view. How can I connect the text and the view so that every time I press the button, the text is drawn to the view?

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  • NSArrayController binding : Suppress "No selection"

    - by Holli
    Hello, I have a texfield bound to an ArrayController. The controller key is "selection" because I select items from a NSTableView. But when there are no items in the table the textfield shows the gray text "no selection". How can I suppress this text and have just an empty textfield? Or how can I change the "No selection" text to something else?

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  • Can't compile code when working with CALayer

    - by Sheehan Alam
    For some reason I get linker errors when I try and use CALayer: "_OBJC_CLASS_$_CALayer", referenced from: I have imported the following headers: #import <Foundation/Foundation.h> #import <UIKit/UIKit.h> #import <QuartzCore/QuartzCore.h> Code: arrowImage = [[CALayer alloc] init];

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  • How to handle an array of pointers in Objective-C

    - by DougW
    I figured out the answer to this question, but I couldn't find the solution on here, so posting it for posterity. So, in Objective-C, how do you create an object out of a pointer in order to store it in objective-c collections (NSArray, NSDictionary, NSSet, etc) without reverting to regular C?

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