【发布时间】：2015-05-27 14:19:48
【问题描述】：
我是 MagicalRecord 的新手。我从不同的方法更新相同的实体时遇到问题。这是我的例子：我有一些从网络服务获得的广告。完成后，如果有任何将它们的活动属性设置为 0，我需要更新数据库中的广告。立即，我需要调用保存我的广告的函数或只更新它们。之后，我需要删除所有过期的广告，然后删除不活动的广告。这些广告实际上是基于语言的，所以每次我更改应用程序的语言时，一些广告就会变得无效。它需要是这样的。这是我的保存和删除代码：
- (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从我的视图模型中调用它们，在我的 RAC 信号的完整块中获取我的广告：
[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 时并未完成，因此一切都无法正常工作。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。？
【问题讨论】：
标签： ios objective-c core-data magicalrecord