编译器错误“使用未声明的标识符”当我删除我的@synthesize语句 [英] Compiler error "use of undeclared identifier" when I remove my @synthesize statements

问题描述

使用最新的LLVM版本，合成属性的要求已删除。

With the latest LLVM build, the requirement for synthesizing properties has been removed.

因此，我能够删除所有的 @synthesize 语句，除了 NSFetchedResultsController 的语句。有没有人知道为什么当我删除 @synthesize fetchedResultsController; 行时，编译器警告我？

Therefore I was able to remove all my @synthesize statements except for the ones for NSFetchedResultsController. Does anyone know why the compiler is warning me when I remove the @synthesize fetchedResultsController; line?

错误： / p>

Error:

使用未声明的标识符fetchedResultsController，是否意味着_fetchedResultsController？

Use of undeclared identifier "fetchedResultsController", did you mean _fetchedResultsController?

这是我的代码：

@property (nonatomic, strong) NSFetchedResultsController *fetchedResultsController;

@synthesize fetchedResultsController;

- (NSFetchedResultsController *)fetchedResultsController {
    if (fetchedResultsController) {
        return fetchedResultsController;
    }

    if (!self.managedObjectContext) {
        self.managedObjectContext = [(MyAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
    }

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Session" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];

    [fetchRequest setPredicate: self.predicate];

    [fetchRequest setFetchBatchSize:20];

    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];
    NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];

    [fetchRequest setSortDescriptors:sortDescriptors];

    fetchedResultsController= [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
    fetchedResultsController.delegate = self;

    NSError *error = nil;
    if (![fetchedResultsController performFetch:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

    return fetchedResultsController;
}

推荐答案

在您的代码中创建一个 @synthesize ，创建的背景属性的实例变量名为 _propertyName 。您指的是在删除 @synthesize 后不再存在的实例变量 fetchedResultsController 。请改为将 feticedResultsController 的所有引用更改为 _fetchedResultsController 。

When you don't put an @synthesize in your code, the instance variable created to back the property is named _propertyName. You are referring to the instance variable fetchedResultsController which no longer exists after you remove the @synthesize. Instead, change all references to fetchedResultsController to _fetchedResultsController.

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