memory issue nsobject and nsmutablearray UICollectionView - ios

Question

I added a simple collection view and i add items fetched from my backend , when I add all the objects to a nsmutablearray it takes less memory but when I add the fetched objects to a NSObject while scrolling the collection view it takes more memory .
here is a sample code
myObjectModel.h
#import <Foundation/Foundation.h>
#interface myObjectModel: NSObject
#property (nonatomic, strong) NSString *objectTitle;
#property (nonatomic, strong) NSString *objectDesc;
#property (nonatomic, strong) NSString *objectImgURL;
- (id)initWithObjectTitle:(NSString *)dTitle
objectImgURL:(NSString *)dObjectImgURL
objectDesc:(NSString *)dObjectDesc;
#end
myObjectModel.m
#import "myObjectModel.h"
#implementation myObjectModel
- (id)initWithObjectTitle:(NSString *)dTitle
objectImgURL:(NSString *)dObjectImgURL
objectDesc:(NSString *)dObjectDesc {
self = [super init];
if (self) {
self.objectTitle = dTitle;
self.objectImgURL = dObjectImgURL;
self.objectDesc = dObjectDesc;
}
return self;
}
#end;
then I imported this header to my UIViewController which has a collectionview while fetching all the objects i add this method to add those objects and then save them into a nsmutablearray
BackendlessDataQuery *query = [BackendlessDataQuery query];
query.queryOptions.pageSize = #(100); //set page size
[[backendless.persistenceService of:[Channels class]] find:query response:^(BackendlessCollection *backendlessObjects) {
NSArray *currentPage = [backendlessObjects getCurrentPage];
NSMutableArray *arrData = [[NSMutableArray alloc]init];
for (Objects *objects in currentPage) {
#autoreleasepool {
myObjectModel *dataItem = [[myObjectModel alloc]initWithObjectTitle:backendlessObjects.title
objectImgURL:backendlessObjects.image
objectDesc:backendlessObjects.Desc;
[arrData addObject:dataItem];
}
//Test is a nsarray added in the header file
self.test = arrData;
[self.collectionView reloadData];
} error:^(Fault *fault) {
}];
here is what I add to my collection data source
#pragma mark - UICollectionViewDatasource
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView; {
return 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return [test count];
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
myCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"data" forIndexPath:indexPath];
myObjectModel *dataItem = (myObjectModel*)[test objectAtIndex:indexPath.row];
// cell.objectTitle.text = dataItem.objectTitle;
[cell.channelImg sd_setImageWithURL:[NSURL URLWithString:dataItem.objectImgURL] placeholderImage:[UIImage imageNamed:#"NoImage.png"]];
return cell;
}
when I run this code all my objects will appear in the collectionview but while scrolling the memory keeps increasing.

Answer 1

There is no reason to increase memory by using test Array the reason is by using this
[cell.channelImg sd_setImageWithURL:[NSURL URLWithString:dataItem.objectImgURL] placeholderImage:[UIImage imageNamed:#"NoImage.png"]];
this will Asynchronously download image from URL.if you comment above line then it may not increase memory.