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  • Consecutive 'if' statements

    - by Ben Packard
    How can I check one thing AND THEN another, if the first is true? For example, say I have a shopping basket object, and I only want to do something if the basket has been created AND it isn't empty. I've tried: if (basket && [basket numberOfItems >0])... But the second condition is evaluated even if the first fails, resulting in a crash (presumably because i'm calling numberOfItems on an object that doesn't exist). I can nest them, but this seems a bit ugly, and more to the point is problematic. Say I want to do one thing if the basket exists AND isn't empty, but another if either isn't true. That doesn't really work well in nested if statements.

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  • Custom UITableViewCell not appearing when row height is set

    - by Sheehan Alam
    I have a custom UITableViewCell which I have created in IB. My labels display when I don't over-ride: - (CGFloat)tableView:(UITableView *)tblView heightForRowAtIndexPath:(NSIndexPath *)indexPath however my content is squished. I want the height to be 120px so I have the following: - (CGFloat)tableView:(UITableView *)tblView heightForRowAtIndexPath:(NSIndexPath *)indexPath { CGFloat rowHeight = 120; return rowHeight; } I'm not sure why the content inside of my UITableViewCell all of a sudden disappears?

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  • How do I implement TimeOut in idarkstar?

    - by malik
    Hi, A little background on the question: I am developing a RedDwarf(http://reddwarfserver.org/) client on iphone, for the client/server communication I use idarkstar. I had to make minor modifications to make it work till now. So here's the question, if the server is taking to long to respond or the network is very slow, how do I add a timeout functionality to make sure it doesn't keep waiting on the server forever? appreciate any pointers.

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  • How to detect touch in triangle area

    - by Romain
    For my application, i need to divide diagonally the screen of my iphone in 4 parts and detect which of the part was touched. I am very confused because my areas are triangles and not squares and I can't find a solution to detect which of the triangle was touched... I get the touched Point with method touchesBegan, and there I'm stuck... :( How to define triangle shapes and test if it was touched? with View? layer? It could be really cool if someone could help me.

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  • How to use generic (NSObject) controller with subviews of a UIViewController?

    - by wanderlust
    I have a UIViewController that is loading several subviews at different times based on user interaction. I originally built all of these subviews in code, with no nib files. Now I am moving to nib files with custom UIView subclasses. Some of these subviews display static data, and I am using loadNibNamed:owner:options: to load them into the view controller. Others contain controls that I need to access. I (sort of) understand the reasons Apple says to use one view controller per screen of content, using generic controller objects (NSObjects) to manage subsections of a screen. So I need a view controller, a generic controller, a view class and a nib. How do I put this all together? My working assumptions and subsequent questions: I will associate the view class with the nib in the 'class identity' drop down in IB. The view controller will coordinate overall screen interactions. When necessary, it will create an instance of the generic controller. Does the generic controller load the nib? How? Do I define the outlets and actions in that view class, or should they be in the generic controller? How do I pass messages between the view controller and the generic controller? If anyone can point me to some sample code using a controller in this way, it will go a long way to helping me understand. None of the books or stackoverflow posts I've read have quite hit the spot yet.

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  • Crashes in Core Data's Inferred Mapping Model Creation (Lightweight Migration). Threading Issue?

    - by enchilada
    I'm getting random crashes when creating an inferred mapping model (with Core Data's lightweight migration) within my application. By the way, I have to do it programmatically in my application while it is running. This is how I create this model (after I have made proper currentModel and newModel objects, of course): NSMappingModel *mappingModel = [NSMappingModel inferredMappingModelForSourceModel:currentModel destinationModel:newModel error:&error]; The problem is this: This method is crashing randomly. When it works, it works just fine without issues. But when it crashes, it crashes my application (instead of returning nil to signify that the method failed, as it should). By randomly, I mean that sometimes it happens and sometimes not. It is unpredictable. Now, here is the deal: I'm running this method in another thread. More precisely, it is located inside a block that is passed via GCD to run on the global main queue. I need to do this for my UI to appear crisp to the user, i.e. so that I can display a progress indicator while the work is underway. The strange thing seems to be that if I remove the GCD stuff and just let it run on the main thread, it seems to be working fine and never crashing. Thus, could it be because I'm running this on a different thread that this is crashing? I somehow find that weird because I don't believe I'm breaking any Core Data rules regarding multi-threading. In particular, I'm not passing any managed objects around, and whenever I need access to the MOC, I create a new MOC, i.e. I'm not relying on any MOC (or for that matter: anything) that has been created earlier on the main thread. Besides the little MOC stuff that occurs, occurs after the mapping model creation method, i.e. after the point at which the app crashes, so it can't possibly be a cause of the crashes under consideration here. All I'm doing is taking two MOMs and asking for a mapping model between them. That can't be wrong even under threading, now can it? Any ideas on what could be going on?

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  • Core Data - 'calculated' attributes

    - by nephilim
    I have two entities: A and B A has two properties from and to, both pointing to the B entity. B as a fetched property to A with predicate from == $FETCH_SOURCE or to = $FETCH_SOURCE -- (from) -> A -- (to) -> B <- (As) -- In my application I select a certain B instance, and then show all of its A instances. Now, in my table the columns are bound to an array controller containing the selected A instances. I want to 'merge' the from and to columns. I already know one of the columns will be equal to the selected B instance, so now I'm only interested in the second value. The options I see: create a custom class for the B entity and create a method that returns either value. It should somehow be able to retrieve which B instance is currently selected. create a custom DataSource. Most columns are still using bindings, so then we'd have to access the NSArrayController's array so we're sure we have the right object. create a custom DataSource, remove the NSArrayController and do all the Core Data stuff ourselves. Is there any 'right' way to solve this?

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  • Leak in NSScanner category method

    - by jluckyiv
    I created an NSScanner category method that shows a leak in instruments. - (BOOL)scanBetweenPrefix:(NSString *)prefix andSuffix:(NSString *)suffix intoString:(NSString **)value { NSCharacterSet *charactersToBeSkipped = [self charactersToBeSkipped]; [self setCharactersToBeSkipped:nil]; BOOL result = NO; // find the prefix; the scanString method below fails if you don't do this if (![self scanUpToString:prefix intoString:nil]) { MY_LOG(@"Prefix %@ is missing.", prefix); return result; } //scan the prefix and discard [self scanString:prefix intoString:nil]; // scan the important part and save it if ([self scanUpToString:suffix intoString:value]) // this line leaks { result = YES; } [self setCharactersToBeSkipped:charactersToBeSkipped]; return result; } I figure it's the way I'm passing the value to/from the method, but I'm not sure. It's a small leak (32 bytes), but I'd like to do this right if I can. Thanks in advance.

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  • How to move a symlink to the trash?

    - by neoneye
    I don't see any options for the FSPathMoveObjectToTrashSync() function for not following links. Here is what I have tried Create a link and a file [ 21:32:41 /tmp ] $ touch my_file [ 21:32:45 /tmp ] $ ln -s my_file my_link [ 21:32:52 /tmp ] $ la total 8 drwxrwxrwt 12 root wheel 408 17 Maj 21:32 . drwxr-xr-x@ 6 root wheel 204 9 Sep 2009 .. -rw-r--r-- 1 neoneye wheel 0 17 Maj 21:32 my_file lrwxr-xr-x 1 neoneye wheel 7 17 Maj 21:32 my_link -> my_file Move the link to the trash OSStatus status = FSPathMoveObjectToTrashSync( "/tmp/my_link", NULL, kFSFileOperationDefaultOptions ); NSLog(@"status: %i", (int)status); Output is status: 0 However the file got removed and not the link [ 21:32:55 /tmp ] $ la total 8 drwxrwxrwt 11 root wheel 374 17 Maj 21:33 . drwxr-xr-x@ 6 root wheel 204 9 Sep 2009 .. lrwxr-xr-x 1 neoneye wheel 7 17 Maj 21:32 my_link -> my_file [ 21:33:05 /tmp ] $ How can I move move symlinks to the trash? The Solution.. thanks to Rob Napier NSString* path = @"/tmp/my_link"; OSStatus status = 0; FSRef ref; status = FSPathMakeRefWithOptions( (const UInt8 *)[path fileSystemRepresentation], kFSPathMakeRefDoNotFollowLeafSymlink, &ref, NULL ); NSAssert((status == 0), @"failed to make FSRef"); status = FSMoveObjectToTrashSync( &ref, NULL, kFSFileOperationDefaultOptions ); NSLog(@"status: %i", (int)status);

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  • NSWindowController and isWindowLoaded

    - by Jim
    Hi, I have an NSWindowController and I initialize it like this; + (MyWindowController *) sharedController { static MyWindowController *singleton = nil; if (!singleton) singleton = [[self alloc] initWithWindowNibName: @"myWindow"]; return singleton; } and I show windows like this; [[MyWindowController sharedController] showWindow: nil]; Now the problem is that I need information from some controls on that window. But I do not want to load the window if it's not yet loaded because then I can just go with the defaults. Should I use @property to access the singleton? or what is recommended here? (If @property, then please give me the readonly, nonatomic attributes too.)

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  • NSMutableArray Problem - iPhone

    - by David Schiefer
    Hi, I'm trying to get a UITableView to read it's data from a file. I've attempted it like this: NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *fullFileName = [NSString stringWithFormat:@"%@/entries.plist", documentsDirectory]; self.dataForTable = [[NSMutableArray alloc] initWithContentsOfFile:fullFileName]; This compiles fine, but when saving something to the file in the following snippet, the file is not saved nor anything is written to the array: NSMutableDictionary*userDictionary; userDictionary = [[NSMutableDictionary alloc] init]; [userDictionary setObject:name.text forKey:@"name"]; [userDictionary setObject:email.text forKey:@"email"]; [userDictionary setObject:serial.text forKey:@"serial"]; [userDictionary setObject:notes.text forKey:@"notes"]; [userDictionary setObject:[NSNumber numberWithInt:[licenseType selectedRowInComponent:0]] forKey:@"license_type"]; [userDictionary setObject:[date date] forKey:@"date"]; [userDictionary setObject:[NSNumber numberWithBool:[paymentSwitch isOn]] forKey:@"payment"]; NSString*dirToSaveTo = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]; NSString*fileName = [NSString stringWithFormat:@"%@.plist",name.text]; NSString*saveName = [dirToSaveTo stringByAppendingPathComponent:fileName]; [userDictionary writeToFile:saveName atomically:NO]; NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *fullFileName = [NSString stringWithFormat:@"%@/entries.plist", documentsDirectory]; [self.dataForTable addObject:name.text]; NSLog(@"%@",self.dataForTable); [self.dataForTable writeToFile:fullFileName atomically:YES]; The NSLog just returns (null). The *plist file is never written. What am I doing wrong?

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  • Comparing against NSLocalizedString safe?

    - by George
    Hi, Sometimes I need to compare interface elements to other objects. At the moment I'm doing it by comparing their titles against a localized string. Am I right that I better compare my objects against IBOutlets? Tags are out of the question because I'm using NSMenu.

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  • Statusbar overlaps ViewController

    - by Stefan
    Hi, I in my AppDelegate, I use: ActivitiesViewController *acController = [[ActivitiesViewController alloc] initWithNibName:@"ActivitiesView" bundle:[NSBundle mainBundle]]; UINavigationController *acNavController = [[UINavigationController alloc] initWithRootViewController:acController]; [self.tabBarController setSelectedIndex:0]; [self.tabBarController setSelectedViewController:acNavController]; To switch the views in my TabBarController. The result is to close to the window top: How do I get my view to correct position? Regards

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  • iPhone "touchesBegan" and "touchesMoved" message ... do not move to centre of touch

    - by Nippysaurus
    I am modifying the "MoveMe" example from the apple web site. When I get the "touchesMoved" message I move the centre of the target view to the centre of the touch. Is there a way that when the touch starts ("touchesBegan" message) I can remember the offset from the target view and keep that offset. Let me know if this is hard to understand and I will try to explain it a bit better.

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  • Can I create a UITableViewController that inherits from a custom subclass of UIViewController?

    - by prendio2
    I have common functionality that I need to access from all screens of my app: a right bar button item and associated action. So as not to repeat the code I would like to set this up in a custom UIViewController and have all my view controllers inherit from it. - (void)viewDidLoad { UIBarButtonItem *rightBarButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemPlay target:self action:@selector(lightsCamera)]; self.navigationItem.rightBarButtonItem = rightBarButton; } - (void)lightsCamera { … } However, I have a number of UITableViewControllers however and I would like to know if it is possible for them to inherit the functionality too?

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  • How do I allow users to dial numbers in my tableView cells?

    - by Griffo
    Hi all, I have a table containing cells with phone numbers. How can I allow the user to dial these numbers by tapping the row? It's not working by default and there's no option in interface builder like there is for uiwebviews so I imagine I need to programmatically tell the app to dial the number when the cell is tapped.

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  • Conditionally overriding a system method via categories in Objective-C?

    - by adib
    Hi Is there a way to provide a method implementation (that bears the exact same name of a method defined by the framework) only when the method isn't already defined in the system? For example method [NSSomeClass someMethod:] exists only in Mac OS X 10.6 and if my app runs in 10.5, I will provide that method's definition in a category. But when the app runs in 10.6, I want the OS-provided method to run. Background: I'm creating an app targeted for both 10.5 and 10.6. The problem is that I recently realized that method +[NSSortDescriptor sortDescriptorWithKey:ascending:] only exists in 10.6 and my code is already littered by that method call. I could provide a default implementation for it (since this time it's not too difficult to implement it myself), but I want the "native" one to be called whenever my app runs on 10.6. Furthermore if I encounter similar problems in the future (with more difficult-to-implement-myself methods), I might not be able to get away with providing a one-liner replacement. This question vaguely similar to Override a method via ObjC Category and call the default implementation? but the difference is that I want to provide implementations only when the system doesn't already has one. Thanks.

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  • initializer not constant?

    - by fuzzygoat
    Quick question if I may: I am just curious about the following (see below) Xcode says "initializer element is not constant" why this does not work, I guess its the NSArray ... static NSArray *stuffyNames = [NSArray arrayWithObjects:@"Ted",@"Dog",@"Snosa",nil]; and this does ... static NSString *stuffyNames[3] = {@"Ted",@"Dog",@"Snosa"}; gary

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  • Puzzled with nib files...

    - by Michael
    I know nib files are serialized objects and they have owner, outlets to make connections. Using XCode Navigation window template I created application, which in its order created 2 nib files - MainWindow and SecondView. I can't understand how MainWindow is referring to SecondView, there is no connection between those two as far as I can see. SecondView's owner is UIViewController and in MainWindow there is a navigation tab which is also UIViewController. But how they are connected in IB I can't understand... Also I don't understand who is instanciating MainWindow's owner object and where that object is being kept, where is the variable which is UIApplication myApp = [[UIApplication alloc] init]. If I create 10 nib files with UIViewController owner, who will trigger their deserialization? If some class is nib file's owner, what is the essential responsibilities of that class? Is it deserializing nib file into memory? Sorry for unorganized questions, I've been reading numerous articles and docs about nib files, but it is still confusing.

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  • Assigning a selector via SEL type?

    - by fuzzygoat
    I just spotted the following in an online tutorial. It showed 001 as a method for assigning a selector, however I could not get this to work. Am I right in thinking that 001 is not right and 002 is the correct way, or am I doing something wrong with 001? // 001 SEL mySel = [self something]; // 002 SEL mySel = @selector(something); . -(void)something { NSLog(@"YAY"); } Gary

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