iOS使用CoreData实现收藏功能_ios开发教程_开发教程

实现收藏有很多方式，我在自己练习的项目中用CoreData实现了一下收藏功能，注释很少，算是自己做的一个笔记。

首先创建一个工具类继承NSObject,在里面实现所需要的方法.

工具类的.h文件:

typedef NS_ENUM(NSUInteger, SelectInEntities) {

InEntities,
NotInEntities,
SelectError,

};

typedef NS_ENUM(NSUInteger, Entities) {

NewsEntity,
   PostEntity,
  TypeEntity,
  ForumEntity,

};

@interface BFFCoreDataManager : NSObject

// 管理对象上下文(管理者)

@property (readonly, strong, nonatomic) NSManagedObjectContext

managedObjectContext;

// 管理对象模型(表结构)

managedObjectModel;

// 持久化存储协调器(助理)

@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;

// 保存上下文(保存对数据的修改)

(void)saveContext;
// 沙盒路径
(NSURL *)applicationDocumentsDirectory;

//-(SelectInEntities)isInEntities:(Entities)entities

// Model:(id)model;

+(BFFCoreDataManager *)shareBFFCoreDataManager;

(id)isInEntities:(Entities)entities model:(id)model;
(BOOL)has:(NSMutableDictionary )dic arr:(NSArray )array;
///地方分会
(BOOL)hass:(NSMutableDictionary )dic arr:(NSArray )array;
///推荐论坛
(BOOL)hasss:(BFFDiscussModel )model arr:(NSArray )array;
(BOOL)haspost:(BFFSelectModel )model arr:(NSArray )array;
(BOOL)state:(NSArray )arr url:(NSString )url;
(BOOL)states:(NSArray )arr ids:(NSString )ids;
(id)myModel:(id)model;

@property (nonatomic, strong) BFFCoreDataManager *manager;

@end

工具类的.m文件

@implementation BFFCoreDataManager

pragma mark - Core Data stack

@synthesize managedObjectContext = _managedObjectContext;

@synthesize managedObjectModel = _managedObjectModel;

@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;

(BFFCoreDataManager
)shareBFFCoreDataManager

{

/// 单例不能释放
manager = nil;

// 保证线程安全, 该方法只走一次

static dispatch_once_t onceToken;

dispatch_once(&onceToken, ^{
```
manager = [BFFCoreDataManager new];
```
});

return manager;

}

// 获取到沙盒的Document路径
(NSURL *)applicationDocumentsDirectory {

// The directory the application uses to store the Core Data store file. This code uses a directory named "com.lanou3g.TheWorldCar" in the application's documents directory.

return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];

}
(NSManagedObjectModel *)managedObjectModel {

// The managed object model for the application. It is a fatal error for the application not to be able to find and load its model.

if (_managedObjectModel != nil) {
```
return _managedObjectModel;
```
}

NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"TheWorldCar" withExtension:@"momd"];

_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];

return _managedObjectModel;

}
(NSPersistentStoreCoordinator *)persistentStoreCoordinator {

// The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it.

if (_persistentStoreCoordinator != nil) {
```
return _persistentStoreCoordinator;
```
}

// Create the coordinator and store

_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];

NSURL
storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"TheWorldCar.sqlite"];
error = nil;

NSString *failureReason = @"There was an error creating or loading the application's saved data.";

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];

if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error]) {
```
// Report any error we got.
  NSMutableDictionary *dict = [NSMutableDictionary dictionary];
  dict[NSLocalizedDescriptionKey] = @"Failed to initialize the application's saved data";
  dict[NSLocalizedFailureReasonErrorKey] = failureReason;
  dict[NSUnderlyingErrorKey] = error;
  error = [NSError errorWithDomain:@"YOUR_ERROR_DOMAIN" code:9999 userInfo:dict];
  // Replace this 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.
  NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
  abort();
```
}

return _persistentStoreCoordinator;

}
(NSManagedObjectContext *)managedObjectContext {

// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.)

if (_managedObjectContext != nil) {
```
return _managedObjectContext;
```
}

NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];

if (!coordinator) {
```
return nil;
```
}

_managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];

[_managedObjectContext setPersistentStoreCoordinator:coordinator];

return _managedObjectContext;

}

pragma mark - Core Data Saving support

(void)saveContext {

NSManagedObjectContext *managedObjectContext = self.managedObjectContext;

if (managedObjectContext != nil) {

NSError *error = 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.
      NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
      abort();
  }

}

(id)myModel:(id)model{

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

[fetchRequest setEntity:entity];

NSError
error = nil;
fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];

if (fetchedObjects == nil) {
```
NSLog(@"%@", error);
```
}

BFFCollectModel
newsModel = model;

for (Type
type in fetchedObjects) {
```
if ([type.name isEqualToString:newsModel.name]) {
      return type;
  } else {
      return nil;
  }
```
}

return nil;

}

// 判断是否在数据库中

(id)isInEntities:(Entities)entities model:(id)model

{

switch (entities) {

case NewsEntity:
  {
      NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
      NSEntityDescription *entity = [NSEntityDescription entityForName:@"News" inManagedObjectContext:self.managedObjectContext];
      [fetchRequest setEntity:entity];
      NSError *error = nil;
      NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
      if (fetchedObjects == nil) {
          NSLog(@"%@", error);
      }
      BFFNewsModel *newsModel = model;
      for (News *news in fetchedObjects) {
          if ([news.newsLink isEqualToString:newsModel.newsLink]) {
              return news;
          }
      }
      return nil;
  }
      break;
  case PostEntity:
  {
      NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
      NSEntityDescription *entity = [NSEntityDescription entityForName:@"Post" inManagedObjectContext:self.managedObjectContext];
      [fetchRequest setEntity:entity];
      NSError *error = nil;
      NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
      if (fetchedObjects == nil) {
          NSLog(@"%@", error);
      }
      BFFHotModel *hot = model;
      for (Post *post in fetchedObjects) {
          if ([post.postLink isEqualToString:hot.postLink]) {
              return post;
          }
      }
      return nil;
  }
      break;
  case TypeEntity:
  {

  }
      break;
  case ForumEntity:
  {
      NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
      NSEntityDescription *entity = [NSEntityDescription entityForName:@"Line" inManagedObjectContext:self.managedObjectContext];
      [fetchRequest setEntity:entity];
      NSError *error = nil;
      NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
      if (fetchedObjects == nil) {
          NSLog(@"%@", error);
      }
      BFFCarDetailModel *carDetail = model;
      for (Line *line in fetchedObjects) {
          if ([line.seriesId isEqualToString:[NSString stringWithFormat:@"%@", carDetail.seriesId]]) {
              return line;
          }
      }
      return nil;
  }

      break;
  default:
      break;

}

return nil;

}

//爱车俱乐部.人车生活

(BOOL)has:(NSMutableDictionary )dic arr:(NSArray )array{
NSNumber
num = dic[@"forumId"];

for (Forum

forum in array) {
```
if ([forum.postId isEqualToString:num.description]) {
      return YES;
  }
```
}

return NO;

}

///地方分会

(BOOL)hass:(NSMutableDictionary )dic arr:(NSArray )array{
NSNumber
num = dic[@"id"];

for (Forum

forum in array) {
```
if ([forum.postId isEqualToString:num.description]) {
      return YES;
  }
```
}

return NO;

}

///论坛推荐

)model arr:(NSArray
(BOOL)hasss:(BFFDiscussModel )model arr:(NSArray )array{
```
if ([forum.postId isEqualToString:model.forumId.description]) {
      return YES;
  }
```
}

return NO;

}

///帖子收藏

)model arr:(NSArray
(BOOL)haspost:(BFFSelectModel )model arr:(NSArray )array{
```
if ([post.postLink isEqualToString:model.postLink]) {
      return YES;
  }
```
}

return NO;

}

///改变帖子收藏按钮图标

)arr url:(NSString
(BOOL)state:(NSArray )arr url:(NSString )url{
```
if ([post.postLink isEqualToString:url]) {
      return YES;
  }
```
}

return NO;

}

///改变论坛收藏按钮图标

)arr ids:(NSString
(BOOL)states:(NSArray )arr ids:(NSString )ids{
```
if ([forum.postId.description isEqualToString:ids]) {
      return YES;
  }
```
}

return NO;

}

*-(SelectInEntities)isInEntities:(Entities)entities

Model:(id)model

{

switch (entities) {

case NewsEntity:

{

fetchRequest = [[NSFetchRequest alloc] init];

NSEntityDescription

entity = [NSEntityDescription entityForName:@"News" inManagedObjectContext:self.managedObjectContext];

[fetchRequest setEntity:entity];

error = nil;

NSArray

fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];

if (fetchedObjects == nil) {

NSLog(@"%@", error);

}

BFFNewsModel

newsModel = model;

for (News *news in fetchedObjects) {

            if ([news.newsLink isEqualToString:newsModel.newsLink]) {
                return InEntities;
            } else {
                return NotInEntities;
            }

        }

    }
        break;
        case PostEntity:
    {

   }
        break;
        case LineEntity:
    {

   }
        break;
        case ForumEntity:
    {

    }
       break;
   default:
        break;
}
return SelectError;

}

@end

接下来在收藏页面创建一个Button实现收藏

(void)collectionBut:(id)sender{

BFFCollectModel *model = self.tempModel;

if ([self.manager myModel:model] == nil) {

Type *type = [NSEntityDescription insertNewObjectForEntityForName:@"Type" inManagedObjectContext:self.manager.managedObjectContext];
  type.name = model.name;
  type.priceRange = model.priceRange;
  type.photo = model.photo;
  type.uid = [NSString stringWithFormat:@"%@", model.uid];
  [self.manager saveContext];

  self.collectLabel.text = @"已经收藏";
  self.collectLabel.hidden = NO;
  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
      self.collectLabel.hidden = YES;
  });

} else {

[self.manager.managedObjectContext deleteObject:[self.manager myModel:model]];
  [self.manager saveContext];
  self.collectLabel.text = @"已取消收藏";
  self.collectLabel.hidden = NO;
  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
      self.collectLabel.hidden = YES;
  });

}

///在我的收藏页面把数据取出

(void)createLineData

{

self.typeArr = [NSMutableArray array];

NSFetchRequest
fetchRequest = [[NSFetchRequest alloc] init];
entity = [NSEntityDescription entityForName:@"Type" inManagedObjectContext:self.manager.managedObjectContext];

[fetchRequest setEntity:entity];

NSError
error = nil;

NSArray
fetchedObjects = [self.manager.managedObjectContext executeFetchRequest:fetchRequest error:&error];

if (fetchedObjects == nil) {
```
NSLog(@"%@", error);
```
}

[self.typeArr addObjectsFromArray:fetchedObjects];

[self.tableView reloadData];

}

///这些数据都铺在了tableView上接下来实现删除的操作

(void)tableView:(UITableView )tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath )indexPath

{

if (editingStyle == UITableViewCellEditingStyleDelete) {

if (self.titleSegment.selectedSegmentIndex == 0) {
      News *news = self.newsArr[indexPath.row];
      [self.manager.managedObjectContext deleteObject:news];
      [self.manager saveContext];
      [self.newsArr removeObjectAtIndex:indexPath.row];
      [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];
  }else if (self.titleSegment.selectedSegmentIndex == 1){
      Post *post = self.postArr[indexPath.row];
      [self.manager.managedObjectContext deleteObject:post];
      [self.manager saveContext];
      [self.postArr removeObjectAtIndex:indexPath.row];
       [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];
  }else if (self.titleSegment.selectedSegmentIndex == 2){
      Forum *forum = self.forumArr[indexPath.row];
      [self.manager.managedObjectContext deleteObject:forum];
      [self.manager saveContext];
      [self.forumArr removeObjectAtIndex:indexPath.row];
      [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];

  }else{

      Type *type = self.typeArr[indexPath.row];
      [self.manager.managedObjectContext deleteObject:type];
       [self.manager saveContext];
      [self.typeArr removeObjectAtIndex:indexPath.row];
      [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];

  }

}

[self.tableView reloadData];

}

这些就是实现收藏的过程

(责任编辑：好模板)