Block in a loop for paging - objective-c

Question

With the following code I'm trying to read the Instagram API content with paging. In the FOR loop I intent to call the method loopData to get the content with a block which has in every loop a new page id.
...
for (int a = 1; a <= 3; a++)
{
NSLog(#"Loop count: %i", a);
[self loopData];
}
-(void)loopData
{
NSString *next;
next = [Globals sharedGlobalData].nextMaxId;
[client getUserMedia:[userTextField stringValue]
count:kCount
minId:-1
maxId:next
success:^(NSArray *media) {
[textView setString:[media description]];
NSLog(#"Next_Max_Id: %# ", [Globals sharedGlobalData].nextMaxId);
}
failure:^(NSError *error, NSInteger statusCode) {
[self logError:#"media" error:error statusCode:statusCode];
}
];
}
My problem is, that the block runs thee times, but not in every loop cycle. The block runs after the for loop is finished. Therefore the new page id can't passed to the block.
The Log looks like this:
Loop 1
Loop 2
Loop 3
Read content through block
Read content through block
Read content through block
Many thanks for ideas!!
--- Implementation of getUserMedia
// Get a user's media
- (void)getUserMedia:(NSString*)userId // Can be 'self' for the current user
count:(int)count
minId:(int)minId // -1 for start
maxId:(int)maxId // -1 for no upper limit
success:(void (^)(NSArray* media))success
failure:(void (^)(NSError* error, NSInteger statusCode))failure {
// Setup the parameters
NSMutableDictionary* parameters = [NSMutableDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithInt:count], #"count", nil];
if (minId > 0) [parameters setObject:[NSNumber numberWithInt:minId] forKey:#"minId"];
if (maxId > 0) [parameters setObject:[NSNumber numberWithInt:maxId] forKey:#"maxId"];
// Fire the get request
[self getPath:[NSString stringWithFormat:#"users/%#/media/recent", userId]
modelClass:[InstagramMedia class]
parameters:parameters
collection:success
single:nil
failure:failure];
}

Answer 1

The blocks you pass into this method are executed asynchronously. The client starts an asynchronous network request and immediately returns when you call this method. Once the network request succeeds or fails, one of the blocks you passed to it is invoked. This is pretty much the standard behavior of any API that takes blocks to use for callbacks like this.
I'm not completely sure what you're trying to do inside the blocks with respect to the nextID and whatnot, but you need to know this: 1) The blocks will not run within the loop and 2) they will not run in any guaranteed order. So whatever problem you are trying to solve, you will need to keep that in mind.
Hope this helps, and let me know if you have any questions.