Question

这是我的委托.m

#import "TestSaveDataAppDelegate.h"

#import "TestSaveDataViewController.h"

@implementation TestSaveDataAppDelegate

@synthesize window = _window;
@synthesize viewController = _viewController;
@synthesize managedObjectContext = __managedObjectContext;
@synthesize managedObjectModel = __managedObjectModel;
@synthesize persistentStoreCoordinator = __persistentStoreCoordinator;

这是我的NSManagedObjectContext

- (NSManagedObjectContext *)managedObjectContext
{
    if (__managedObjectContext != nil) {
        return __managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        __managedObjectContext = [[NSManagedObjectContext alloc] init];
        [__managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    return __managedObjectContext;
}

这是我的NSManagedObjectModel

- (NSManagedObjectModel *)managedObjectModel
{
    if (__managedObjectModel != nil) {
        return __managedObjectModel;
    }    
    __managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
    return __managedObjectModel;
}

这是我的NSPersistentStoreCoordinator

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (__persistentStoreCoordinator != nil) {
        return __persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"SaveData.sqlite"];

    NSError *error = nil;
    __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }    
    return __persistentStoreCoordinator;
}

在我的TestSaveDataViewController.h中，我导入了我的Savedata.h，就像我的Model.xcdatamodeld里面一样，实体名称是Savedata，这里的属性是带有字符串类型的saveslot1。

在我的TestSaveDataViewController.m

中

@synthesize managedObjectContext;

我有一个像这样的按钮

- (IBAction)button1:(id)sender
{
    // save text in textfield
    Savedata *savedata = (Savedata *)[NSEntityDescription insertNewObjectForEntityForName:@"Savedata" inManagedObjectContext:managedObjectContext];
    [savedata setSaveslot1:label1.text];    
    NSError *error;
    if (![managedObjectContext save:&error]) {
        // This is a serious error saying the record could not be saved.
        // Advise the user to restart the application
    }
}

按下按钮时，文本字段中的文本将保存并显示为label1.text 但我得到了这个错误。

+entityForName: could not locate an NSManagedObjectModel for entity name 'Savedata''

如何解决？

Answer 1

我已经解决了我的问题。我忘了委托它。现在它有效。

error + entityForName：无法找到实体名称“Savedata”的NSManagedObjectModel

1 个答案: