UICollectionView Memory Leak Crash - objective-c

Question

My CollectionView is retrieving images from the Parse network, and keeps crashing. I keep getting memory warnings right before the crash. I'm guessing I need to free up space. But the problem is i'm relatively new to coding so I don't know how to do this. I don't even know where the memory needs to be freed from. Could someone please help me understand what I am doing wrong in my code?
- (void)viewDidLoad {
[super viewDidLoad];
[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:#"NavBar1.png"] forBarMetrics:UIBarMetricsDefault];
// self.navigationController.hidesBarsOnSwipe = true;
[self queryParseMethodCell];
// Do any additional setup after loading the view.
}
- (void)queryParseMethodCell {
NSLog(#"start Money");
PFQuery *query3 = [PFQuery queryWithClassName:#"MainWall"];
PFQuery *query4 = [PFQuery queryWithClassName:#"MainWall"];
[query3 orderByDescending:#"createdAt"];
[query4 orderByAscending:#"createdAt"];
[query3 findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
NSLog(#"check bobby");
imageFilesArray2 = [[NSArray alloc] initWithArray:objects];
[self.HomePost reloadData];
}
else{
NSLog(#"NO Good33");
}
}];
[query4 findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
NSLog(#"check bobby");
imageFilesArray3 = [[NSArray alloc] initWithArray:objects];
[self.HomePost reloadData];
}
else{
NSLog(#"NO Good44");
}
}];
}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView {
if (self.lastContentOffset > scrollView.contentOffset.y) {
[self.navigationController setNavigationBarHidden:NO animated:YES];
}
else if (self.lastContentOffset < scrollView.contentOffset.y){
[self.navigationController setNavigationBarHidden:YES animated:YES];
}
else {
NSLog(#"Andy Error1");
}
}
- (IBAction)SwipeLeft:(UISwipeGestureRecognizer *)sender {
[self performSegueWithIdentifier:#"Notifications" sender:self];
}
- (IBAction)SwipeRight:(UISwipeGestureRecognizer *)sender{
[self performSegueWithIdentifier:#"FavWall" sender:self];
}
- (IBAction)MainWall:(id)sender{
[self performSegueWithIdentifier:#"MainWall" sender:self];
}
- (IBAction)FavWall:(id)sender{
[self performSegueWithIdentifier:#"FavWall" sender:self];
}
- (IBAction)Notifications:(id)sender{
[self performSegueWithIdentifier:#"Notifications" sender:self];
}
- (IBAction)Home:(id)sender{
[self performSegueWithIdentifier:#"Home" sender:self];
}
- (IBAction)YourAccount:(id)sender{
[self performSegueWithIdentifier:#"YourAccount" sender:self];
}
- (IBAction)UsersAccount:(id)sender{
[self performSegueWithIdentifier:#"UsersAccount" sender:self];
}
-(IBAction)PicTake:(id)sender{
[self performSegueWithIdentifier:#"Camera" sender:self];
}
#pragma mark Collection View
-(NSInteger )numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return [imageFilesArray2 count];
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"TopCell";
DiscoverCell *cell = nil;
if (cell == nil) {
cell = (DiscoverCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
}
else {
NSLog(#"2Error");
}
PFObject *imageObject2 = [imageFilesArray2 objectAtIndex:indexPath.row];
cell.Username.text = [imageObject2 objectForKey:#"Name"];
PFFile *imageFile3 = [imageObject2 objectForKey:#"ProfilePicture"];
[imageFile3 getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
NSLog(#"CheckCash");
// cell.TopStory.image = [UIImage imageWithData:data];
cell.HomeImg.image = [UIImage imageWithData:data];
cell.Back.image = [UIImage imageWithData:data];
//cell.HomeImg2.image = [UIImage imageWithData:data];
}
else{
NSLog(#"NO Good");
}
cell.HomeImg.layer.cornerRadius = cell.HomeImg.frame.size.width /2;
cell.HomeImg.clipsToBounds = YES;
cell.Back.image = cell.HomeImg.image;
}];
PFObject *imageObject5 = [imageFilesArray3 objectAtIndex:indexPath.row];
cell.Username.text = [imageObject5 objectForKey:#"Name"];
PFFile *imageFile4 = [imageObject5 objectForKey:#"ProfilePicture"];
[imageFile4 getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
NSLog(#"CheckCash");
cell.TopStory.image = [UIImage imageWithData:data];
}
else{
NSLog(#"NO Good22");
}
}];
return cell;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end

Answer 1

You have a memory leak. Everytime you scroll all images all reloaded. Something like this should solve the problem
//at start For every data DataisNotLoaded should be true
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
if dataisNotLoaded[index] {
DataisNotLoaded[index] = false
[imageFile3 getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
NSLog(#"CheckCash");
// cell.TopStory.image = [UIImage imageWithData:data];
cell.HomeImg.image = [UIImage imageWithData:data];
cell.Back.image = [UIImage imageWithData:data];
//cell.HomeImg2.image = [UIImage imageWithData:data];
}
else{
NSLog(#"NO Good");
}
}