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  • ParseKit.framework won't work, Foundation.h not found

    - by Jeremy
    I'm really stumped trying to get the ParseKit.framework (this) to work in general, not even bothering to implement it till it runs the demo app that comes with it. What happens is the compiler can't locate < Foundation/Foundation.h or something, which I thought the header was in the linked framework. Exact error: "Lexical or Preprocessor Issue: 'Foundation/Foundation.h' file not found." Here's the code, just from the ParseKit_Prefix.pch: // // Prefix header for all source files of the 'ParseKit' target in the 'ParseKit' project. //#ifdef __OBJC__ #import <Foundation/Foundation.h> #endif Nothing unusual about it, did I mess up the file paths some how? I've reinstalled Xcode, re-downloaded the ParseKit, and nothing is helping. The suggestions here did nothing and it's not this. When I make a new project or use a different project and load the Foundation.framework and #import the header it works just fine. If I unlink the framework I can't find it to re-link again. Has anyone else had this kind of problem? Did I download it wrong somewhere? I have a very difficult time finding where exactly the Xcode UI links stuff, apple must get a kick out of frustrating people, so if anyone has anything they can think of please give me some feedback, I'm horribly confused right now. Thanks,

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  • iPhone - How do I find the MAC address of the connected WiFi access point?

    - by Ciaran
    Without using the private APIs, is it possible to programatically determine the MAC address of the access point that the iPhone is connected to? I understand that this should be doable using the core BSD libraries, but we are new to this, so it would be great if someone can point us to some starter code. Note: we're trying to determine the MAC address of the remote device - not the MAC address of the iPhone.

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  • How can I conditionally color files and folders in the OS X Finder?

    - by Girish Kolari
    I want to color badge files and folders based on the some condition in finder, what is the approach to achieve this in Mac OS X 10.6 I have checked this question: This only talk about the context menu in finder http://stackoverflow.com/questions/1651075/finder-plugin-in-snow-leopard I have even checked: http://scplugin.tigris.org/ even they don't do color badging in 10.6 which is pending task. Thanks in advance for your all help

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  • How to load a NIB inside of a view in another NIB?

    - by Sheehan Alam
    I have two NIB's ParentViewController.xib ChildViewController.xib ParentViewController.xib contains a UIView and a UIViewController. ChildViewController.xib contains a UIButton I want ChildViewController.xib to load in the ParentViewController.xib's UIView I have done the following: Created @property for UIView in ParentViewController Connected File's Owner to UIView in ParentViewController Set UIViewController in ParentViewController's NIB Name property to ChildViewController in Interface Builder Set ChildViewController view property to UIView in ParentViewController I was hoping this would load ChildViewController into my UIView in ParentViewController but no luck. I did get the following warning, which could be the culprit: 'View Controller (Child View)' has both its 'NIB Name' property set and its 'view' outlet connected. This configuration is not supported. I also have added additional code in ParentViewController's viewDidLoad(): - (void)viewDidLoad { [super viewDidLoad]; ChildViewController *childViewController = [[ChildViewController alloc]initWithNibName:@"ChildViewController" bundle:nil]; childViewController.view = self.myView; } Any thoughts on why ChildViewController does not load in the UIView of ParentViewController?

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  • How Can I Compress Texture in OpenGL on iPhone/iPad?

    - by nonamelive
    Hi, I'm making an iPad app which needs OpenGL to do a flip animation. I have a front image texture and a back image texture. Both the two textures are screenshots. // Capture an image of the screen UIGraphicsBeginImageContext(view.bounds.size); [view.layer renderInContext:UIGraphicsGetCurrentContext()]; image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); // Allocate some memory for the texture GLubyte *textureData = (GLubyte*)calloc(maxTextureSize*4, maxTextureSize); // Create a drawing context to draw image into texture memory CGContextRef textureContext = CGBitmapContextCreate(textureData, maxTextureSize, maxTextureSize, 8, maxTextureSize*4, CGImageGetColorSpace(image.CGImage), kCGImageAlphaPremultipliedLast); CGContextDrawImage(textureContext, CGRectMake(0, maxTextureSize-size.height, size.width, size.height), image.CGImage); CGContextRelease(textureContext); // ...done creating the texture data [EAGLContext setCurrentContext:context]; glGenTextures(1, &textureToView); glBindTexture(GL_TEXTURE_2D, textureToView); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, maxTextureSize, maxTextureSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData); // free texture data which is by now copied into the GL context free(textureData); Each of the texture takes up about 8MB memory, which is unacceptable for an iPhone/iPad app. Could anyone tell me how can I compress the texture to reduce the memory. I'm a complete newbie to OpenGL. Any help would be appreciated!

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  • Error copying file from app bundle

    - by Michael Chen
    I used the FireFox add-on SQLite Manager, created a database, which saved to my desktop as "DB.sqlite". I copied the file into my supporting files for the project. But when I run the app, immediately I get the error "Assertion failure in -[AppDelegate copyDatabaseIfNeeded], /Users/Mac/Desktop/Note/Note/AppDelegate.m:32 2014-08-19 23:38:02.830 Note[28309:60b] Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Failed to create writable database file with message 'The operation couldn’t be completed. (Cocoa error 4.)'.' First throw call stack: "... Here is the App Delegate Code where the error takes place -(void) copyDatabaseIfNeeded { NSFileManager *fileManager = [NSFileManager defaultManager]; NSError *error; NSString *dbPath = [self getDBPath]; BOOL success = [fileManager fileExistsAtPath:dbPath]; if (!success) { NSString *defaultDBPath = [[ [NSBundle mainBundle ] resourcePath] stringByAppendingPathComponent:@"DB.sqlite"]; success = [fileManager copyItemAtPath:defaultDBPath toPath:dbPath error:&error]; if (!success) NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]); } } I am very new to Sqlite, so I maybe I didn't create a database correctly in the FireFox Sqlite manager, or maybe I didn't "properly" copy the .sqlite file in? (I did check the target membership in the sqlite and it correctly has my project selected. Also, the .sqlite file names all match up perfectly.)

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  • ObjectiveC - Releasing objects added as parameters

    - by NobleK
    Ok, here goes. Being a Java developer I'm still struggling with the memory management in ObjectiveC. I have all the basics covered, but once in a while I encounter a challenge. What I want to do is something which in Java would look like this: MyObject myObject = new MyObject(new MyParameterObject()); The constructor of MyObject class takes a parameter of type MyParameterObject which I initiate on-the-fly. In ObjectiveC I tried to do this using following code: MyObject *myObject = [[MyObject alloc] init:[[MyParameterObject alloc] init]]; However, running the Build and Analyze tool this gives me a "Potential leak of an object" warning for the MyParameter object which indeed occurs when I test it using Instruments. I do understand why this happens since I am taking ownership of the object with the alloc method and not relinquishing it, I just don't know the correct way of doing it. I tried using MyObject *myObject = [[MyObject alloc] init:[[[MyParameterObject alloc] init] autorelease]]; but then the Analyze tool told me that "Object sent -autorelease too many times". I could solve the issue by modifying the init method of MyParameterObject to say return [self autorelease]; in stead of just return self;. Analyze still warnes about a potential leak, but it doesn't actually occur. However I believe that this approach violates the convention for managing memory in ObjectiveC and I really want to do it the right way. Thanx in advance.

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  • Gradual memory leak in loop over contents of QTMovie

    - by Benji XVI
    I have a simple foundation tool that exports every frame of a movie as a .tiff file. Here is the relevant code: NSString* movieLoc = [NSString stringWithCString:argv[1]]; QTMovie *sourceMovie = [QTMovie movieWithFile:movieLoc error:nil]; int i=0; while (QTTimeCompare([sourceMovie currentTime], [sourceMovie duration]) != NSOrderedSame) { // save image of movie to disk NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSString *filePath = [NSString stringWithFormat:@"/somelocation_%d.tiff", i++]; NSData *currentImageData = [[sourceMovie currentFrameImage] TIFFRepresentation]; [currentImageData writeToFile:filePath atomically:NO]; NSLog(@"%@", filePath); [sourceMovie stepForward]; [arp release]; } [pool drain]; return 0; As you can see, in order to prevent very large memory buildups with the various transparently-autoreleased variables in the loop, we create, and flush, an autoreleasepool with every run through the loop. However, over the course of stepping through a movie, the amount of memory used by the program still gradually increases. Instruments is not detecting any memory leaks per se, but the object trace shows certain General Data blocks to be increasing in size. [Edited out reference to slowdown as it doesn't seem to be as much of a problem as I thought.] Edit: let's knock out some parts of the code inside the loop & see what we find out... Test 1 while (banana) { NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSString *filePath = [NSString stringWithFormat:@"/somelocation_%d.tiff", i++]; NSLog(@"%@", filePath); [sourceMovie stepForward]; [arp release]; } Here we simply loop over the whole movie, creating the filename and logging it. Memory characteristics: remains at 15MB usage for the duration. Test 2 while (banana) { NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSImage *image = [sourceMovie currentFrameImage]; [sourceMovie stepForward]; [arp release]; } Here we add back in the creation of the NSImage from the current frame. Memory characteristics: gradually increasing memory usage. RSIZE is at 60MB by frame 200; 75MB by f300. Test 3 while (banana) { NSAutoreleasePool *arp = [[NSAutoreleasePool alloc] init]; NSImage *image = [sourceMovie currentFrameImage]; NSData *imageData = [image TIFFRepresentation]; [sourceMovie stepForward]; [arp release]; } We've added back in the creation of an NSData object from the NSImage. Memory characteristics: Memory usage is again increasing: 62MB at f200; 75MB at f300. In other words, largely identical. It looks like a memory leak in the underlying system QTMovie uses to do currentFrameImage, to me.

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  • iphone sdk textbox

    - by Amy
    I'm learning programming iphone app. i need some help making a scrollable textbox with a image background. like the ipod music player with lyrics. thx

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  • CoreData: Same predicate (IN) returns different fetched results after a Save operation

    - by Jason Lee
    I have code below: NSArray *existedTasks = [[TaskBizDB sharedInstance] fetchTasksWatchedByMeOfProject:projectId]; [context save:&error]; existedTasks = [[TaskBizDB sharedInstance] fetchTasksWatchedByMeOfProject:projectId]; NSArray *allTasks = [[TaskBizDB sharedInstance] fetchTasksOfProject:projectId]; First line returns two objects; Second line save the context; Third line returns just one object, which is contained in the 'two objects' above; And the last line returns 6 objects, containing the 'two objects' returned at the first line. The fetch interface works like below: WXModel *model = [WXModel modelWithEntity:NSStringFromClass([WQPKTeamTask class])]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(%@ IN personWatchers) AND (projectId == %d)", currentLoginUser, projectId]; [model setPredicate:predicate]; NSArray *fetchedTasks = [model fetch]; if (fetchedTasks.count == 0) return nil; return fetchedTasks; What confused me is that, with the same fetch request, why return different results just after a save? Here comes more detail: The 'two objects' returned at the first line are: <WQPKTeamTask: 0x1b92fcc0> (entity: WQPKTeamTask; id: 0x1b9300f0 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p9> ; data: { projectId = 372004; taskId = 338001; personWatchers = ( "0xf0bf440 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WWPerson/p1>" ); } <WQPKTeamTask: 0xf3f6130> (entity: WQPKTeamTask; id: 0xf3cb8d0 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p11> ; data: { projectId = 372004; taskId = 340006; personWatchers = ( "0xf0bf440 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WWPerson/p1>" ); } And the only one object returned at third line is: <WQPKTeamTask: 0x1b92fcc0> (entity: WQPKTeamTask; id: 0x1b9300f0 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p9> ; data: { projectId = 372004; taskId = 338001; personWatchers = ( "0xf0bf440 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WWPerson/p1>" ); } Printing description of allTasks: <_PFArray 0xf30b9a0>( <WQPKTeamTask: 0xf3ab9d0> (entity: WQPKTeamTask; id: 0xf3cda40 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p6> ; data: <fault>), <WQPKTeamTask: 0xf315720> (entity: WQPKTeamTask; id: 0xf3c23a0 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p7> ; data: <fault>), <WQPKTeamTask: 0xf3a1ed0> (entity: WQPKTeamTask; id: 0xf3cda30 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p8> ; data: <fault>), <WQPKTeamTask: 0x1b92fcc0> (entity: WQPKTeamTask; id: 0x1b9300f0 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p9> ; data: { projectId = 372004; taskId = 338001; personWatchers = ( "0xf0bf440 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WWPerson/p1>" ); }), <WQPKTeamTask: 0xf325e50> (entity: WQPKTeamTask; id: 0xf343820 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p10> ; data: <fault>), <WQPKTeamTask: 0xf3f6130> (entity: WQPKTeamTask; id: 0xf3cb8d0 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WQPKTeamTask/p11> ; data: { projectId = 372004; taskId = 340006; personWatchers = ( "0xf0bf440 <x-coredata://CFFD3F8B-E613-4DE8-85AA-4D6DD08E88C5/WWPerson/p1>" ); }) ) UPDATE 1 If I call the same interface fetchTasksWatchedByMeOfProject: in: #pragma mark - NSFetchedResultsController Delegate - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { I will get 'two objects' as well. UPDATE 2 I've tried: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(ANY personWatchers == %@) AND (projectId == %d)", currentLoginUser, projectId]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(ANY personWatchers.personId == %@) AND (projectId == %d)", currentLoginUserId, projectId]; Still the same result. UPDATE 3 I've checked the save:&error, error is nil.

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  • Problem with close socket

    - by zp26
    Hi, I have a problem with my socket program. I create the client program (my code is below) I have a problem when i close the socket with the disconnect method. Can i help me? Thanks and sorry for my English XP CFSocketRef s; -(void)CreaConnessione { CFSocketError errore; struct sockaddr_in sin; CFDataRef address; CFRunLoopSourceRef source; CFSocketContext context = { 0, self, NULL, NULL, NULL }; s = CFSocketCreate( NULL, PF_INET, SOCK_STREAM, IPPROTO_TCP, kCFSocketDataCallBack, AcceptDataCallback, &context); memset(&sin, 0, sizeof(sin)); int port = [fieldPorta.text intValue]; NSString *tempIp = fieldIndirizzo.text; const char *ip = [tempIp UTF8String]; sin.sin_family = AF_INET; sin.sin_port = htons(port); sin.sin_addr.s_addr = (long)inet_addr(ip); address = CFDataCreate(NULL, (UInt8 *)&sin, sizeof(sin)); errore = CFSocketConnectToAddress(s, address, 0); if(errore == 0){ buttonInvioMess.enabled = TRUE; fieldMessaggioInvio.enabled = TRUE; labelTemp.text = [NSString stringWithFormat:@"Connesso al Server"]; CFRelease(address); source = CFSocketCreateRunLoopSource(NULL, s, 0); CFRunLoopAddSource(CFRunLoopGetCurrent(), source, kCFRunLoopDefaultMode); CFRelease(source); CFRunLoopRun(); } else{ labelTemp.text = [NSString stringWithFormat:@"Errore di connessione. Verificare Ip e Porta"]; switchConnection.on = FALSE; } } //the socket doesn't disconnect -(void)Disconnetti{ CFSocketInvalidate(s); CFRelease(s); } -(IBAction)Connetti { if(switchConnection.on) [self CreaConnessione]; else [self Disconnetti]; }

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  • UItableView Problem in deleting items from database

    - by Arun Sharma
    Hi All, I am using in UitableView database.My table view works successfully (add single item,add multiple item,delete all) only problem is there when i want to delete single item for this i using Uitableview edit option. so how i add database method for deleting single item from database and also from table view. Please help me.

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  • Recursively find files/directories within a directory

    - by enchilada
    I want to use enumeratorAtURL:includingPropertiesForKeys:options:errorHandler: to do this, as I'm coding under Snow Leopard. I know how to use this method. However, as for my purposes it's not adequate to load the contents lazily, I have the following question: How can I create an object hierarchy (of, say, the custom FileOrDirectory class with the standard children,count,isLeaf attributes) from the information I load from the enumeratorAtURL: method? I need to load this data beforehand, and show it in an outline view, for my purposes.

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  • Changing the title of a MFMailComposeViewController

    - by Badescu Alexandru
    Although i know changing MFMailComposeViewController is fround upon, i'm taking a risk. I found some ideas such as [self presentModalViewController:controller animated:YES]; // Existing line [[[[controller viewControllers] lastObject] navigationItem] setTitle:@"SomethingElse"]; and [[[[(MFMailComposeViewController*)vc navigationBar] items] objectAtIndex:0] setTitle:@" SomethingElse"]; but the odd thing is that the title is "SomethingElse" for like 2 seconds and after that it returns to the subject that is set. I've tried other solutions as well but the same output. I am using SHK (ShareKit) to connect to social. Here is the code from showViewController : if ([vc respondsToSelector:@selector(modalPresentationStyle)]) vc.modalPresentationStyle = [SHK modalPresentationStyle]; if ([vc respondsToSelector:@selector(modalTransitionStyle)]) vc.modalTransitionStyle = [SHK modalTransitionStyle]; [topViewController presentModalViewController:vc animated:YES]; [[[[(MFMailComposeViewController*)vc navigationBar] items] objectAtIndex:0] setTitle:@" "]; [(UINavigationController *)vc navigationBar].barStyle = [(UINavigationController *)vc toolbar].barStyle = [SHK barStyle]; self.currentView = vc;

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  • iPhone OS: making a switch statement that uses string literals as comparators instead of integers

    - by nickthedude
    So i'd like to do this: switch (keyPath) { case @"refreshCount": //do stuff case @"timesLaunched": //do other stuff } but apparently you can only use integers as the switch quantity. Is the only way to do this parse the string into an integer identifier and then run the switch statement? like this: nsinteger num = nil; if (keyPath isEqual:@"refreshCount") { num = 0 } if (keyPath isEqual:@"timesLaunched") { num = 1 } I'm trying to optimize this code to be as quick as possible because its going to get called quite often. thanks, Nick

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  • Using Kal calendar without doing the initialization (and so on) in the AppDelegate

    - by testing
    I'm using the Kal calendar. For the code shown below I'm referring to the Holiday example. In this example the allocation and initialization of Kal is done in the applicationDidFinishLaunching in the AppDelegate. The UITableViewDelegate protocol (e.g. didSelectRowAtIndexPath) is also positioned in the AppDelegate class. The AppDelegate: #import "HolidayAppDelegate.h" #import "HolidaySqliteDataSource.h" #import "HolidaysDetailViewController.h" ## Heading ###import "Kal.h" @implementation HolidayAppDelegate @synthesize window; - (void)applicationDidFinishLaunching:(UIApplication *)application { kal = [[KalViewController alloc] init]; kal.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithTitle:@"Today" style:UIBarButtonItemStyleBordered target:self action:@selector(showAndSelectToday)] autorelease]; kal.delegate = self; dataSource = [[HolidaySqliteDataSource alloc] init]; kal.dataSource = dataSource; // Setup the navigation stack and display it. navController = [[UINavigationController alloc] initWithRootViewController:kal]; [window addSubview:navController.view]; [window makeKeyAndVisible]; } // Action handler for the navigation bar's right bar button item. - (void)showAndSelectToday { [kal showAndSelectDate:[NSDate date]]; } #pragma mark UITableViewDelegate protocol conformance // Display a details screen for the selected holiday/row. - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { Holiday *holiday = [dataSource holidayAtIndexPath:indexPath]; HolidaysDetailViewController *vc = [[[HolidaysDetailViewController alloc] initWithHoliday:holiday] autorelease]; [navController pushViewController:vc animated:YES]; } #pragma mark - - (void)dealloc { [kal release]; [dataSource release]; [window release]; [navController release]; [super dealloc]; } @end I don't want to put this into the AppDelegate, because there could be some overlapping code with other views. It should be a separate "component" which I can call and put on the stack. In my navigation based project I have a main view, the RootViewController. From there I want to push the Kal view on the stack. Currently I'm pushing an additional ViewController on the stack. In the viewWillAppear method from this ViewController I do the things shown in the code above. The following problems appear: Navigation back has to be done two times (one for the Kal calendar, one for my created view) Navigation to my main view is not possible anymore In the moment I don't know where to put this code. So the question is where to put the methods for allocation/initialization as well as the methods for the UITableViewDelegate protocol.

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  • iPhone not returning to application after calling eMail send

    - by Bill
    I am sending an email from within my iPhone application. The eMail page pops up ok, I click on the Send button, the iPhone plays a whoosh sound, and the eMail actually arrives at the recipient. Unfortunately, the mail dialog still sits there unresponsive, and the only option - to click the home button - kills the app. Is there something else that needs to be specified to close the eMailMessage view? MFMailComposeViewController *eMailMessage; NSArray *toAddress; if ([MFMailComposeViewController canSendMail]) { toAddress = [NSArray arrayWithObject:@"[email protected]"]; eMailMessage = [[MFMailComposeViewController alloc] init]; [eMailMessage setToRecipients:toAddress]; [eMailMessage setSubject:@"Notification"]; [eMailMessage setMessageBody:@"Performed by ..." isHTML:NO]; [self presentModalViewController:eMailMessage animated:YES]; [eMailMessage release]; }

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  • handling the logout functionality on the iPhone

    - by Nanz
    This is the first iPhone application i am working on. To use the application, the user has to login to our server. I am done with that part. Now the problem i am facing is how to logout the user from the server, deallocate all the memory and start afresh without quitting the app. After the user logs out, i want the exact same things to happen as in applicationdidfinishlaunching method. But i dont know how to go about it. The app has a tab bar which is set up in mainWindow.xib.

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  • Setting up a "to-many" relationship value dependency for a transient Core Data attribute

    - by Greg Combs
    I've got a relatively complicated Core Data relationship structure and I'm trying to figure out how to set up value dependencies (or observations) across various to-many relationships. Let me start out with some basic info. I've got a classroom with students, assignments, and grades (students X assignments). For simplicity's sake, we don't really have to focus much on the assignments yet. StudentObj <--->> ScoreObj <<---> AssignmentObj Each ScoreObj has a to-one relation with the StudentObj and the AssignmentObj. ScoreObj has real attributes for the numerical grade, the turnInDate, and notes. AssignmentObj.scores is the set of Score objects for that assignment (N = all students). AssignmentObj has real attributes for name, dueDate, curveFunction, gradeWeight, and maxPoints. StudentObj.scores is the set of Score objects for that student (N = all assignments). StudentObj also has real attributes like name, studentID, email, etc. StudentObj has a transient (calculated, not stored) attribute called gradeTotal. This last item, gradeTotal, is the real pickle. it calculates the student's overall semester grade using the scores (ScoreObj) from all their assignments, their associated assignment gradeWeights, curves, and maxPoints, and various other things. This gradeTotal value is displayed in a table column, along with all the students and their individual assignment grades. Determining the value of gradeTotal is a relatively expensive operation, particularly with a large class, therefore I want to run it only when necessary. For simplicity's sake, I'm not storing that gradeTotal value in the core data model. I don't mind caching it somewhere, but I'm having a bitch of a time determining where and how to best update that cache. I need to run that calculation for each student whenever any value changes that affects their gradeTotal. If this were a simple to-one relationship, I know I could use something like keyPathsForValuesAffectingGradeTotal ... but it's more like a many-to-one-to-many relationship. Does anyone know of an elegant (and KVC correct) solution? I guess I could tear through all those score and assignment objects and tell them to register their students as observers. But this seems like a blunt force approach.

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