ios - 从 Core Data 中检索单个对象

Question

在我的应用程序中，有多个画廊。所以我创建了一个名为 Gallery 的实体并插入了一些对象。像这样，

NSManagedObjectContext *context = [self managedObjectContext];

Gallery *gallery1 = [NSEntityDescription insertNewObjectForEntityForName:@"Gallery" inManagedObjectContext:context];
gallery1.galleryId = @1;
gallery1.galleryName = @"Art";
gallery1.galleryDesc = @"Some info about art";

Gallery *gallery2 = [NSEntityDescription insertNewObjectForEntityForName:@"Gallery" inManagedObjectContext:context];
gallery2.galleryId = @2;
gallery2.galleryName = @"Architecture";
gallery2.galleryDesc = @"details about architecture";

NSError *error;
if (![context save:&error]) {
    NSLog(@"Error Ocurred When Saving: %@", error.localizedDescription);
}

现在在 View Controller 中，我需要根据所选画廊检索有关特定画廊的描述。

下面是我到目前为止的代码

NSFetchRequest *fetchRequst = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Gallery" inManagedObjectContext:self.managedObjectContext];
fetchRequst.entity = entity;
NSError *error;
// Gets the Gallery objects to an array
self.galleries = [self.managedObjectContext executeFetchRequest:fetchRequst error:&error];

// self.gallery is passed in to this view controller from the previous one
if ([self.gallery isEqualToString:@"Art"]) {
    self.galleryInfoTextView.text = gallery.galleryDesc;
} else if ([self.gallery isEqualToString:@"Architecture"]) {
    self.galleryInfoTextView.text = gallery.galleryDesc;
} 

如何仅检索对象，例如 Art，然后显示其描述？

Answer 1

NSArray *galleryArray = [self.managedObjectContext executeFetchRequest:fetchRequst error:&error];


    for (Gallery *gallery in galleryArray)
    {
        if(gallery.galleryName isEqualToString:@"Art"){
            //this is gallery Object is of Art
         } else if (gallery.galleryName isEqualToString:@"Architecture"){
             //this is gallery Object is of Architecture
         }
    }