Calling specific method after another method - ios

Question

I'm retrieving data from my parse database and looping it into an NSMutableArray. This is in my getHomes method, which is being called in viewDidLoad. The NSMutableArray contain various UIImages, which CGSize' i'm looping through. This method is called getCellHeights. I want to call this method right after the getHomes method, but stacking them like this in viewdidLoad does not do the trick. The getCellHeights method is not running since there is no objects in the NSMutableArray, cause its not completed with the retrieving of data.
How can i make sure that the getCellHeights is not running before the getHomes method is completed?
getCellHeights
-(void)getcellHeights {
for (int i = 0; i < homesDic.count; i++) {
UIImage *image = [[homesDic objectAtIndex:i] objectForKey:#"image"];
CGFloat divider = image.size.width/145;
CGFloat wantedWidth = 145;
CGFloat wantedHeight = image.size.height/divider;
NSLog(#"width: %f height: %f", wantedWidth, wantedHeight);
CGSize size = CGSizeMake(wantedWidth, wantedHeight);
[_cellSizes addObject:[NSValue valueWithCGSize:size]];
}
}
getHomes
-(void)getHomes {
PFQuery *query = [PFQuery queryWithClassName:#"Homes"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects1, NSError *error) {
if (!error) {
for (PFObject *object in objects1) {
PFQuery *userQ = [PFUser query];
[userQ getObjectInBackgroundWithId:[object objectForKey:#"userId"] block:^(PFObject *userName, NSError *error) {
NSLog(#"%#", userName);
[[userName objectForKey:#"file"] getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
UIImage *profileImage = [UIImage imageWithData:data];
PFQuery *homeQ = [PFQuery queryWithClassName:#"homeImages"];
[homeQ whereKey:#"homeId" equalTo:object.objectId];
[homeQ whereKey:#"number" equalTo:#(0)];
[homeQ findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
PFQuery *cityQ = [PFQuery queryWithClassName:#"City"];
id zip = [NSNumber numberWithInteger: [[object objectForKey:#"zip"] intValue]];
[cityQ whereKey:#"fra" greaterThanOrEqualTo:zip];
[cityQ whereKey:#"fra" lessThanOrEqualTo:zip];
[cityQ findObjectsInBackgroundWithBlock:^(NSArray *cObject, NSError *error) {
if (!error) {
PFObject *cityObject = [cObject lastObject];
PFObject *image = [objects lastObject];
[[image objectForKey:#"Image"] getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
UIImage *image = [UIImage imageWithData:data];
NSMutableDictionary *flagDict = [[NSMutableDictionary alloc] init];
[flagDict setObject:[object objectForKey:#"title"] forKey:#"title"];
[flagDict setObject:image forKey:#"image"];
[flagDict setObject:[cityObject objectForKey:#"navn"] forKey:#"city"];
[flagDict setObject:[userName objectForKey:#"name"] forKey:#"name"];
[flagDict setObject:profileImage forKey:#"profileImage"];
[homesDic addObject:flagDict];
[self.collectionView reloadData];
} else {
// Log details of the failure
NSLog(#"Error: %# %#", error, [error userInfo]);
}
}];
}
}];
}
}];
}];
}];
}
} else {
// Log details of the failure
NSLog(#"Error: %# %#", error, [error userInfo]);
}
}];
}

Answer 1

The Blocks that you're passing to the Parse framework query methods are completion/callback Blocks; when the fetch has completed, they are run. Do whatever you need to do after the fetch -- including calling cellHeights -- in the appropriate completion Block.