错误：[__NSCFConstantString 路径]：发送了无法识别的选择器

Posted 2023-03-08

【中文标题】错误：[__NSCFConstantString 路径]：发送了无法识别的选择器

【英文标题】：Error: [__NSCFConstantString path]: unrecognized selector sent

【发布时间】：2012-11-12 18:12:30

【问题描述】：

我正在尝试实现 Core Data 与 iCloud 的同步。

当我尝试 [self fetchedResultsControllerICloud] performFetch:&error] in

-(id)init

    [self managedObjectModelICloud];
    [self managedObjectContextICloud];

    if (![[self fetchedResultsControllerICloud] performFetch:&error]) 
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        exit(-1);  // Fail
    

我有一个错误

 2012-11-12 23:50:34.917 My English words[1072:907] iCloud access at file://localhost/private/var/mobile/Library/Mobile%20Documents/LUB2V2L4R3~ru~________~My-English-words/
 2012-11-12 23:50:34.920 My English words[1072:907] count: 0
 2012-11-12 23:50:34.935 My English words[1072:110b] iCloudData: /private/var/mobile/Library/Mobile Documents/LUB2V2L4R3~ru~________~My-English-words/Documents/My_English_words.sqlite
 2012-11-12 23:50:34.938 My English words[1072:110b] -[__NSCFConstantString path]: unrecognized selector sent to instance 0x8ca28
 2012-11-12 23:50:34.940 My English words[1072:110b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFConstantString path]: unrecognized selector sent to instance 0x8ca28'
 *** First throw call stack:
 (0x331012a3 0x33fbf97f 0x33104e07 0x33103531 0x3305af68 0x344b840b 0x343805cf 0x3437e73d 0x7fe33 0x356f111f 0x356ff259 0x356ff3b9 0x3572fa11 0x3572f8a4)
 libc++abi.dylib: terminate called throwing an exception
 (lldb)

与 [_persistentStoreCoordinatorICloud addPersistentStoreWithType:NSSQLiteStoreType 字符串 在 - (NSPersistentStoreCoordinator *)persistentStoreCoordinatorICloud 方法中

#define sqlLiteDataBaseName @"My_English_words.sqlite"
#define sqlLiteDataBasePath @"Documents"
#define iCloudEnabledAppID @"LUB2V2L4R3.ru.________.My-English-words"

//************************************************

- (NSManagedObjectContext *)managedObjectContextICloud

    if (_managedObjectContextICloud != nil) 
        return _managedObjectContextICloud;
    

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinatorICloud];
    if (coordinator != nil) 
        _managedObjectContextICloud = [[NSManagedObjectContext alloc] init];
        [_managedObjectContextICloud setPersistentStoreCoordinator:coordinator];
    
    return _managedObjectContextICloud;

//************************************************

- (NSManagedObjectModel *)managedObjectModelICloud

    if (_managedObjectModelICloud != nil) 
        return _managedObjectModelICloud;
    
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"My_English_words" withExtension:@"momd"];
    _managedObjectModelICloud = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    return _managedObjectModelICloud;

//************************************************
    - (NSPersistentStoreCoordinator *)persistentStoreCoordinatorICloud
    
        NSURL *iCloud = [[NSFileManager defaultManager] URLForUbiquityContainerIdentifier:nil];
        NSLog(@"iCloud access at %@", iCloud);
        NSString *pathString=[[iCloud path] stringByAppendingPathComponent:sqlLiteDataBasePath];
        _persistentStoreCoordinatorICloud = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModelICloud]];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^

        if([[NSFileManager defaultManager] fileExistsAtPath:pathString] == NO)
        
            NSLog(@"!Exist");
            NSError *fileSystemError;
            [[NSFileManager defaultManager] createDirectoryAtPath:pathString
                                      withIntermediateDirectories:YES
                                                       attributes:nil
                                                            error:&fileSystemError];
            if(fileSystemError != nil) 
                NSLog(@"Error creating database directory %@", fileSystemError);
            

        

        NSString *iCloudData = [[[iCloud path] stringByAppendingPathComponent:sqlLiteDataBasePath] stringByAppendingPathComponent:sqlLiteDataBaseName];
        NSLog(@"iCloudData: %@",iCloudData);
        NSMutableDictionary *options = [NSMutableDictionary dictionary];
        [options setObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption];
        [options setObject:[NSNumber numberWithBool:YES] forKey:NSInferMappingModelAutomaticallyOption];
        [options setObject:iCloudEnabledAppID            forKey:NSPersistentStoreUbiquitousContentNameKey];
        [options setObject:sqlLiteDataBasePath           forKey:NSPersistentStoreUbiquitousContentURLKey];


        [_persistentStoreCoordinatorICloud lock];

        [_persistentStoreCoordinatorICloud addPersistentStoreWithType:NSSQLiteStoreType
                                                        configuration:nil
                                                                  URL:[NSURL fileURLWithPath:iCloudData]
                                                              options:options
                                                                error:nil];

        [_persistentStoreCoordinatorICloud unlock];

        dispatch_async(dispatch_get_main_queue(), ^
            NSLog(@"asynchronously added persistent store!");
            [[NSNotificationCenter defaultCenter] postNotificationName:@"RefetchAllDatabaseData" object:self userInfo:nil];
        );
    );    
    return _persistentStoreCoordinatorICloud;

//************************************************
    - (NSFetchedResultsController *)fetchedResultsControllerICloud

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"OriginalWords" inManagedObjectContext:_managedObjectContextICloud];
    [fetchRequest setEntity:entity];

    NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"date" ascending:NO];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
    [fetchRequest setFetchBatchSize:1000];

    NSFetchedResultsController *theFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest
                                                                                                  managedObjectContext:_managedObjectContextICloud
                                                                                                    sectionNameKeyPath:nil
                                                                                                             cacheName:nil];

    self.fetchedResultsControllerICloud  = theFetchedResultsController;
    _fetchedResultsControllerICloud.delegate = self;

    return _fetchedResultsControllerICloud;

【问题讨论】：

某处你有一个 NSString 可能应该有一个 NSURL。如果您查看异常回溯，它会告诉您在哪里。

我怀疑 iCloud 变量没有被正确地带入块上下文中。如果您在块内调用URLForUbiquityContainerIdentifier: 方法而不是使用iCloud 会怎样？ （如果它消除了错误消息，它会缩小问题范围。）

感谢您的建议，真的很有趣，尽管有这个错误，运行这个脚本后，sqlite 文件是在 iCloud 中创建的。

错误已解决。问题出在 [options setObject:sqlLiteDataBasePath forKey:NSPersistentStoreUbiquitousContentURLKey]; #define sqlLiteDataBasePath @"Documents" 非常愚蠢的错误，但现在我遇到了另一个错误：'这个 NSPersistentStoreCoordinator 没有持久存储。它无法执行保存操作”。我认为这是由于 [_managedObjectContextICloud save:&error]

【参考方案1】：

错误已解决。问题出在

[options setObject:sqlLiteDataBasePath forKey:NSPersistentStoreUbiquitousContentURLKey];

sqlLiteDataBasePath路径应该是完整的

[[iCloud URLByAppendingPathComponent:sqlLiteDataBasePath] URLByAppendingPathComponent:sqlLiteDataBaseName]

非常愚蠢的错误，但现在我又遇到了一个错误：

'This NSPersistentStoreCoordinator has no persistent stores. It cannot perform a save operation'. 

我认为这是由于

[_managedObjectContextICloud save:&error]

【讨论】：

解决了！答案是：您也可能做错了修改上下文（例如向其中添加新的托管对象），然后在存储初始化之前尝试保存它。