在数据库Objective C中本地保存JSON响应

Question

我有一个针对GET API请求的questioAnswer responseObject：

{＆＃34; 7d2c591c-9056-405c-9509-03266842b7e5＆＃34 =（）;＆＃34; f884a7d1-f9d9-4563-bb6e-94538664f3bd＆＃34; =测试;}

如何针对特定调查uuid在数据库中本地保存？

Answer 1

您可以将其保存在会话中。

环境：

NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];

[userDefaults setObject:value 
                 forKey:key];
[userDefaults synchronize];

获得：

[[NSUserDefaults standardUserDefaults] objectForKey:key];

修改

只是为了阐述您将Core Data添加到之前没有它的项目中实际需要执行的所有步骤：

第1步：添加框架

点击您的应用目标（在左侧窗格中显示带有应用名称的顶部图标），然后转到“构建阶段”标签，然后点击“链接二进制文件库”，点击“+”链接然后找到'CoreData.framework'并将其添加到您的项目

然后使用以下方法在所有需要的对象上导入coredata（非性感方式）：

<强>夫特

import CoreData

目标C

#import <CoreData/CoreData.h>

或在.pch文件中添加常见导入下方的导入（更加性感），如下所示：

#ifdef __OBJC__
    #import <UIKit/UIKit.h>
    #import <Foundation/Foundation.h>
    #import <CoreData/CoreData.h>
#endif

第2步：添加数据模型

要添加.xcdatamodel文件，请右键单击/按住Control键并单击右侧窗格中的文件（如在“资源”文件夹中保存），然后选择“添加新文件”，在选择文件类型时单击“核心数据”选项卡然后单击“数据模型”，为其命名并单击“下一步”和“完成”，它将把它添加到您的项目中。当您单击此Model对象时，您将看到使用您想要的任何关系将实体添加到项目的界面。

第3步：更新应用代理

在AppDelegate.swift上的 Swift

//replace the previous version of applicationWillTerminate with this
func applicationWillTerminate(application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    // Saves changes in the application's managed object context before the application terminates.
    self.saveContext()
}

func saveContext () {
    var error: NSError? = nil
    let managedObjectContext = self.managedObjectContext
    if managedObjectContext != nil {
        if managedObjectContext.hasChanges && !managedObjectContext.save(&error) {
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            //println("Unresolved error \(error), \(error.userInfo)")
            abort()
        }
    }
}

// #pragma mark - Core Data stack

// Returns the managed object context for the application.
// If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
var managedObjectContext: NSManagedObjectContext {
    if !_managedObjectContext {
        let coordinator = self.persistentStoreCoordinator
        if coordinator != nil {
            _managedObjectContext = NSManagedObjectContext()
            _managedObjectContext!.persistentStoreCoordinator = coordinator
        }
    }
    return _managedObjectContext!
}
var _managedObjectContext: NSManagedObjectContext? = nil

// Returns the managed object model for the application.
// If the model doesn't already exist, it is created from the application's model.
var managedObjectModel: NSManagedObjectModel {
    if !_managedObjectModel {
        let modelURL = NSBundle.mainBundle().URLForResource("iOSSwiftOpenGLCamera", withExtension: "momd")
        _managedObjectModel = NSManagedObjectModel(contentsOfURL: modelURL)
    }
    return _managedObjectModel!
}
var _managedObjectModel: NSManagedObjectModel? = nil

// Returns the persistent store coordinator for the application.
// If the coordinator doesn't already exist, it is created and the application's store added to it.
var persistentStoreCoordinator: NSPersistentStoreCoordinator {
    if !_persistentStoreCoordinator {
        let storeURL = self.applicationDocumentsDirectory.URLByAppendingPathComponent("iOSSwiftOpenGLCamera.sqlite")
        var error: NSError? = nil
        _persistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
        if _persistentStoreCoordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: storeURL, options: nil, error: &error) == nil {
            /*
            Replace this implementation with code to handle the error appropriately.
            abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            Typical reasons for an error here include:
            * The persistent store is not accessible;
            * The schema for the persistent store is incompatible with current managed object model.
            Check the error message to determine what the actual problem was.
            If the persistent store is not accessible, there is typically something wrong with the file path. Often, a file URL is pointing into the application's resources directory instead of a writeable directory.
            If you encounter schema incompatibility errors during development, you can reduce their frequency by:
            * Simply deleting the existing store:
            NSFileManager.defaultManager().removeItemAtURL(storeURL, error: nil)
            * Performing automatic lightweight migration by passing the following dictionary as the options parameter:
            [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true}
            Lightweight migration will only work for a limited set of schema changes; consult "Core Data Model Versioning and Data Migration Programming Guide" for details.
            */
            //println("Unresolved error \(error), \(error.userInfo)")
            abort()
        }
    }
    return _persistentStoreCoordinator!
}
var _persistentStoreCoordinator: NSPersistentStoreCoordinator? = nil

// #pragma mark - Application's Documents directory

// Returns the URL to the application's Documents directory.
var applicationDocumentsDirectory: NSURL {
    let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)
    return urls[urls.endIndex-1] as NSURL
}

在Objective C中，确保将这些对象添加到AppDelegate.h

 @property (nonatomic, retain, readonly) NSManagedObjectModel *managedObjectModel;
 @property (nonatomic, retain, readonly) NSManagedObjectContext *managedObjectContext;
 @property (nonatomic, retain, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator;

 - (NSURL *)applicationDocumentsDirectory; // nice to have to reference files for core data

在AppDelegate.m中合成以前的对象，如下所示：

@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;

然后将这些方法添加到AppDelegate.m（确保将您添加的模型的名称放在显示的位置）：

- (void)saveContext{
    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil) {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        }
    }
}

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

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

- (NSManagedObjectModel *)managedObjectModel{
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"NAMEOFYOURMODELHERE" withExtension:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    return _managedObjectModel;
}

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

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"NAMEOFYOURMODELHERE.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;
}

 #pragma mark - Application's Documents directory

// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

第4步：将数据对象提供给您需要数据的ViewControllers

选项1.使用VC中的App Delegate的ManagedObjectContext（首选和更简单）

由@ brass-kazoo建议 - 通过以下方式检索对AppDelegate及其managedObjectContext的引用：

<强>夫特

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
 appDelegate.managedObjectContext

目标C

 [[[UIApplication sharedApplication] delegate] managedObjectContext];

选项2.在VC中创建ManagedObjectContext并使其与AppDelegate（原始）中的AppDelegate匹配

仅显示Objective C的旧版本，因为更容易使用首选方法

ViewController.h中的

@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;

在ViewController.m

中

@synthesize managedObjectContext = _managedObjectContext;

在AppDelegate或创建ViewController的类中，将managedObjectContext设置为与AppDelegate相同

ViewController.managedObjectContext = self.managedObjectContext;

如果您希望使用Core Data的viewcontroller成为FetchedResultsController，那么您需要确保这些内容在ViewController.h中

@interface ViewController : UIViewController <NSFetchedResultsControllerDelegate> {
  NSFetchedResultsController *fetchedResultsController;
  NSManagedObjectContext *managedObjectContext;
}

 @property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController;

这是在ViewController.m

中

@synthesize fetchedResultsController, managedObjectContext;

完成所有这些之后，您现在可以使用此managedObjectContext来运行CoreData良好所需的所有常用fetchRequests！享受

Answer 2

如果你想存储在coredata中（使用离线），那么只需创建一个实体并将元组插入到实体中。

只需按照以下链接获取Core数据教程： Core data Tutorial AppCoda

如果您还可以使用UserDefaults来存储特定数据。

希望有所帮助

Answer 3

谢谢你们！但我尝试使用FMDB创建数据库（因为它已经集成）并且它正确地创建了新的答案表但是在保存上面的字典时遇到了麻烦，因为它具有动态键值配对。