Question

在我的应用程序中，执行获取请求应用程序时随机冻结。我尝试了多个选择，如@synchronized和performblock仍然挂起发生。下面是我的第一个获取请求块。应用程序随机挂起此获取请求。

+(BXXXX *)getDetailsById:(NSNumber *)Id
    {
        NSFetchRequest *fetch = [[NSFetchRequest alloc] init];
        NSEntityDescription *entityDescription = [NSEntityDescription

                                                  entityForName:@"BXXXX"  inManagedObjectContext:[SDataManager managedObjectContext]];
        [fetch setEntity:entityDescription];
        [fetch setPredicate:[NSPredicate predicateWithFormat:
                             @"(BId = %@)",Id]];


        __block NSArray *bDetails;
        [[SDataManager managedObjectContext] performBlockAndWait:^{
            NSError *error = nil;
            bDetails = [[SDataManager managedObjectContext] executeFetchRequest:fetch error:&error];

        }];

        if([bDetails count] == 1)
            return [bDetails objectAtIndex:0];
        else
            return nil;

    }

// MY管理对象上下文声明

+(NSManagedObjectContext *)managedObjectContext
{
    static NSManagedObjectContext *managedObjectContext;
    if(managedObjectContext!=nil){
        return managedObjectContext;
    }
    @try { 
        NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
        if (coordinator != nil) {
            managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
            [managedObjectContext setPersistentStoreCoordinator: coordinator];
        }
    }
    @catch (NSException *exception) {
        NSLog(@"Exception occur %@",exception);
    }
        return managedObjectContext;

}

请指导我解决此问题。我努力了，但我现在还无法解决这个问题。

Answer 1

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

您的托管对象上下文将在主队列上执行所有操作。这将阻止主事件循环并导致您的应用似乎挂起。

将工作移出主队列。请参阅Core Data Concurrency Guide。

Answer 2

I have fixed this issue by creating two managed object context like this.
// Base
    +(NSManagedObjectContext *)managedObjectContext
    {
        static NSManagedObjectContext *managedObjectContext;
        if(managedObjectContext!=nil){
            return managedObjectContext;
        }
        @try { 
            NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
            if (coordinator != nil) {
                managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
                [managedObjectContext setPersistentStoreCoordinator: coordinator];
            }
        }
        @catch (NSException *exception) {
            NSLog(@"Exception occur %@",exception);
        }
            return managedObjectContext;

    }

//Child

    +(NSManagedObjectContext *)childManagedObjectContext
    {
        static NSManagedObjectContext *managedObjectContext;
        if(managedObjectContext!=nil){
            return managedObjectContext;
        }
        @try {
            NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
            if (coordinator != nil) {
                managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
                [managedObjectContext setPersistentStoreCoordinator: coordinator];
            }
        }
        @catch (NSException *exception) {
            NSLog(@"Exception occur %@",exception);
        }
        return managedObjectContext;

    }

用于执行获取请求我使用了并发类型的子管理对象上下文作为NSPrivateQueueConcurrencyType。它对我来说很好。现在UI挂起不存在。

执行获取请求时应用程序冻结

2 个答案: