Question

我是MagicalRecord的新手。我在从不同方法更新相同实体时遇到问题。这是我的例子：我从网络服务获得了一些广告。完成后，如果有任何将其active属性设置为0，我需要更新数据库中的Ads。我需要立即调用Save函数来存储我的广告或只更新它们。之后，我需要删除所有过期日期的广告，之后删除非活动广告。这些广告实际上是基于语言的，因此每次我更改应用程序的语言时，某些广告都会变为非活动状态。它需要像那样。这是我保存和删除的代码：

- (void) saveBanners:(NSDictionary *)activeBanner
{
      NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
     [formatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss"];

if (activeBanner != nil || [activeBanner count] != 0)
{
    for (int i = 0; i<[activeBanner.banners count]; i++)
    {
        NSDate *dateTo = [formatter dateFromString:[activeBanner.banners[i] DateValidTo]];
        NSDate *dateFrom = [formatter dateFromString:[activeBanner.banners[i] DateValidFrom]];
        NSLog(@"%@ %@", dateTo, [activeBanner.banners[i] DateValidTo]);

        [MagicalRecord
         saveWithBlock:^(NSManagedObjectContext *localContext)
         {
             Banner *banner = [Banner MR_findFirstByAttribute:@"serverId" withValue:[activeBanner.banners[i] ID] inContext:localContext];
             Banner *localBanner;
             if (banner != nil)
             {
                 localBanner = [banner MR_inContext:localContext];
             }
             else
             {
                 localBanner = [Banner MR_createInContext:localContext];
             }

             localBanner.serverId = [activeBanner.banners[i] ID];
             localBanner.name = [activeBanner.banners[i] Name];
             localBanner.text = [activeBanner.banners[i] BannerText];
             localBanner.dateFrom = dateFrom;
             localBanner.dateTo = dateTo;
             localBanner.image = [activeBanner.banners[i] ImageData];
             localBanner.active = [NSNumber numberWithBool:YES];
             localBanner.country = [activeBanner.banners[i] CountryCode];
         }];
    }
}
}

- (void)setBannerInactive:(NSString *)country
{

NSPredicate *bannerFilter = [NSPredicate predicateWithFormat:@"country IN %@", @[[country uppercaseString]]]; // paziti na upperCase, tako vraca u bazi
NSArray *banners = [Banner MR_findAllWithPredicate:bannerFilter];
NSNumber *bannersCount = [Banner MR_numberOfEntitiesWithPredicate:bannerFilter];

if (bannersCount.integerValue != 0)
{
    for (int i = 0; i < bannersCount.integerValue; i++)
    {

        [MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext)
         {
             Banner *banner = [Banner MR_findFirstByAttribute:@"serverId" withValue:[banners[i] serverId] inContext:localContext];

             if (banner != nil)
             {
                 Banner *localBanner = [banner MR_inContext:localContext];
                 localBanner.active = [NSNumber numberWithBool:NO];
             }
         } completion:^(BOOL success, NSError *error) {
             NSLog(@"I am here");
         }];
    }
}
}

- (void)deleteInactiveBanners
{

NSPredicate *inactiveBannerFilter = [NSPredicate predicateWithFormat:@"active = NO"]; // NO = neaktivni
NSArray *banners = [Banner MR_findAllWithPredicate:inactiveBannerFilter];

if (banners != nil || [banners count] != 0)
{
    for (int i = 0; i < [banners count]; i++)
    {
        Banner *banner = banners[i];

        if (banner != nil)
        {
            [MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext)
             {
                 Banner *localBanner = [banner MR_inContext:localContext];
                 [localBanner MR_deleteEntity];
             }];
        }
    }

}
}

我在我的视图控制器中通过我的RAC信号的完整块中的视图模型调用它们来获取我的广告：

 [self.viewModel setBannerInactive:appLanguage];

     if (self.viewModel.activeBanner != nil)
     {
         [self.viewModel saveBanner:self.splashViewModel.activeBanner];
     }

     [self.viewModel deleteInactiveBanners];

我知道saveWithBlocks是在后台线程中执行的。问题是当我调用setBannerInactive时，它在调用saveBanners时没有完成，所以一切都不能正常工作。如何使用MagicalRecord正确调用这些方法。我使用的是最新的2.x MagicalRecord，而不是v3。？

Answer 1

像这样的东西（我没有尝试过，也没有尝试编译它，所以它可能包含错误，但想法就在那里）

- (void) saveBanners:(NSDictionary *)activeBanner withCompletion:(void(^)())completionBlock
{
      NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
     [formatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss"];

if (activeBanner != nil || [activeBanner count] != 0)
{
    for (int i = 0; i<[activeBanner.banners count]; i++)
    {
        NSDate *dateTo = [formatter dateFromString:[activeBanner.banners[i] DateValidTo]];
        NSDate *dateFrom = [formatter dateFromString:[activeBanner.banners[i] DateValidFrom]];
        NSLog(@"%@ %@", dateTo, [activeBanner.banners[i] DateValidTo]);

        [MagicalRecord
         saveWithBlock:^(NSManagedObjectContext *localContext)
         {
             Banner *banner = [Banner MR_findFirstByAttribute:@"serverId" withValue:[activeBanner.banners[i] ID] inContext:localContext];
             Banner *localBanner;
             if (banner != nil)
             {
                 localBanner = [banner MR_inContext:localContext];
             }
             else
             {
                 localBanner = [Banner MR_createInContext:localContext];
             }

             localBanner.serverId = [activeBanner.banners[i] ID];
             localBanner.name = [activeBanner.banners[i] Name];
             localBanner.text = [activeBanner.banners[i] BannerText];
             localBanner.dateFrom = dateFrom;
             localBanner.dateTo = dateTo;
             localBanner.image = [activeBanner.banners[i] ImageData];
             localBanner.active = [NSNumber numberWithBool:YES];
             localBanner.country = [activeBanner.banners[i] CountryCode];
         } completion:^(BOOL success, NSError *error) {
if(completionBlock)
completionBlock();
             NSLog(@"I am here");
         }];
    }
}
}

- (void)setBannerInactive:(NSString *)country withCompletion:(void(^)())completionBlock
{

NSPredicate *bannerFilter = [NSPredicate predicateWithFormat:@"country IN %@", @[[country uppercaseString]]]; // paziti na upperCase, tako vraca u bazi
NSArray *banners = [Banner MR_findAllWithPredicate:bannerFilter];
NSNumber *bannersCount = [Banner MR_numberOfEntitiesWithPredicate:bannerFilter];

if (bannersCount.integerValue != 0)
{
    for (int i = 0; i < bannersCount.integerValue; i++)
    {

        [MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext)
         {
             Banner *banner = [Banner MR_findFirstByAttribute:@"serverId" withValue:[banners[i] serverId] inContext:localContext];

             if (banner != nil)
             {
                 Banner *localBanner = [banner MR_inContext:localContext];
                 localBanner.active = [NSNumber numberWithBool:NO];
             }
         } completion:^(BOOL success, NSError *error) {
             NSLog(@"I am here");
if(completionBlock)
completionBlock();
         }];
    }
}
}

- (void)deleteInactiveBanners withCompletion:(void(^)())completionBlock
{

NSPredicate *inactiveBannerFilter = [NSPredicate predicateWithFormat:@"active = NO"]; // NO = neaktivni
NSArray *banners = [Banner MR_findAllWithPredicate:inactiveBannerFilter];

if (banners != nil || [banners count] != 0)
{
    for (int i = 0; i < [banners count]; i++)
    {
        Banner *banner = banners[i];

        if (banner != nil)
        {
            [MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext)
             {
                 Banner *localBanner = [banner MR_inContext:localContext];
                 [localBanner MR_deleteEntity];
             } completion:^(BOOL success, NSError *error) {
             NSLog(@"I am here");
if(completionBlock)
completionBlock();
         }];
        }
    }

}
}

像这样使用它

[self.viewModel setBannerInactive:appLanguage withCompletion:^(){

 if (self.viewModel.activeBanner != nil)
 {
     [self.viewModel saveBanner:self.splashViewModel.activeBanner withCompletion:^(){
         [self.viewModel deleteInactiveBanners withCompletion:nil];
      }];
 }
else
{     
     [self.viewModel deleteInactiveBanners withCompletion:nil];
}
}];

MagicalRecord调用多个保存方法

1 个答案: