iOS 更新 dispatch_async 中的 RLMObject

Question

I would like to update RLMObject in dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0) and get result in dispatch_get_main_queue(), but object updated in other thread is not updated in main ui thread. What is solution? Example code is:

Result is:Age of dogs1: 9Age of dogs2: 9

but it should be:Age of dogs1: 9Age of dogs2: 11

// Create a standalone object
Dog *mydog = [[Dog alloc] init];

// Set & read properties
mydog.name = @"Rex2";
mydog.age = 9;
NSLog(@"Name of dog: %@", mydog.name);

// Realms are used to group data together
RLMRealm *realm = [RLMRealm defaultRealm]; // Create realm pointing to default file

// Save your object
[realm beginWriteTransaction];
[realm addObject:mydog];
[realm commitWriteTransaction];

// Multi-threading
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    RLMRealm *otherRealm = [RLMRealm defaultRealm];
    RLMResults *otherResults = [Dog objectsInRealm:otherRealm where:@"name contains 'Rex2'"];
    Dog* dog = [otherResults firstObject];

    NSLog(@"Age of dogs1: %ld", (long)dog.age);

    [otherRealm beginWriteTransaction];
    dog.age = 11;
    [otherRealm commitWriteTransaction];

    dispatch_async(dispatch_get_main_queue(), ^{
        RLMRealm *otherRealm2 = [RLMRealm defaultRealm];
        RLMResults *otherResults2 = [Dog objectsInRealm:otherRealm2 where:@"name contains 'Rex2'"];
        Dog* dog2 = [otherResults2 firstObject];

        NSLog(@"Age of dogs2: %ld", (long)dog2.age);
    });
});

Answer 1

如果你在它们各自的调度块的顶部调用[otherRealm refresh]和[otherRealm2 refresh] ，这将确保给定的领域正在查看数据库中最新的事务。