CODEWITHSUNDEEP
ioscore-data
booker
booker

Reputation: 1286

Core Data saving progress

I would like to know if I could have information about saving progress of NSManagedObjectContext.

if (![self.context save:&error]) 
{
    NSLog(@"Unresolved error %@", error);
    [self.context rollback];
    return NO;
}

I need to save a lot of stuff so the saving could take a lot of time... I need to inform the user about the progress in percentage.

Upvotes: 2

Views: 777

Answers (2)

Jody Hagins
Jody Hagins

Reputation: 28409

The method easiest is to just make changes to the MOC in small chunks, saving each small change. However, in order to do a true percentage you have to know the total amount of work in the first place... or make a good guess and update the total as you go.

Anyway, you could do something like this...

dispatch_async(some_queue, ^{
    while (workToDo) {
        getSomeWorkToDo();
        doTheCurrentPieceOfWork();
        // Save current piece of work practicing Safe Core Data
        [managedObjectContext performBlock:^{
            if (![managedObjectContext save:&error]) {
                // Handle error
            }
        }];
        computePercentageComplete();
        dispatch_async(dispatch_get_main_queue(), ^{
            // Update the control with the new percent complete
        });
    }
});

Upvotes: 1

runmad
runmad

Reputation: 14886

Unfortunately there isn't really a process for Core Data saves and it varies from device to device - saves on 4S is much faster than 3GS for example.

What you may be able to do is do several saves. I did this for one project. I was looping through a lot of XML and for every 20 loops I would save the context and update a progress bar. This made the whole parsing + saving process seem a bit faster visually. It may actually also help speed things up because saving a small chunk of data at a time was faster for me than saving all the changes to the context at the end. I ended up with a magic number of 17 saves in my loop, which was the fastest parsing time for me, so you can play around with the number a bit.

You can also just show an activity view (spinner) which is an indefinite way or providing visual feedback to a user on the saving process.

Upvotes: 2

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