enumerateLinesUsingBlock完成时如何获得通知

Question

Is there any way to notify when a enumerateLinesUsingBlock is completed? Please check below code. I am calling createFastSearchData method with chunk by chunk data in a while loop and inside that taking each lines and processing it. In while condition I am checking the length of the main string and I want to continue untill it completes the total length. So I want to make sure that enumerateLinesUsingBlock is completed before the while loop trigger again.

while(<checking the length of the mainstring>){
   [self createFastSearchData:string];
}


- (void)createFastSearchData:(NSString *)newChunk{
     [newChunk enumerateLinesUsingBlock:^(NSString * line, BOOL * stop)
         {}];
}

Added:

I am working with blocks and finding difficulty to understand the actual flow. Please check the below code. I want to call fetchCSVData method by passing different values in an array filesToBeFetchedWhat . I want to make sure that, fetchCSVData should not overlap. How can I do that? Please help

    dispatch_async( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        @autoreleasepool {
            for (int i = 0; i < filesToBeFetched.count; i++) {
                [applicationDelegate fetchCSVData:[filesToBeFetched objectAtIndex:i]];
            }
        }
        dispatch_async( dispatch_get_main_queue(), ^{
            NSLog(@"Fetching is done *********************");
        });
    });

Answer 1

To answer the first part of the question:

All enumerate...UsingBlock methods don't work asynchronously.

Regarding the added part:

Assuming fetchCSVData works also synchronously, that's the preferred way to process the data

dispatch_async( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    @autoreleasepool {
       for (int i = 0; i < filesToBeFetched.count; i++) {
          [applicationDelegate fetchCSVData:[filesToBeFetched objectAtIndex:i]];
          dispatch_async( dispatch_get_main_queue(), ^{
            NSLog(@"Fetching is done *********************");
          });
       }
    }
});