Array Objects update without assign - ios

Question

I want to add image from Gallery/Camera to NSMutableDictionary & i am using following methods which i found Here
[dict setObject:UIImageJPEGRepresentation(chosenImage,0.5) forKey:#"image_four"];
[documents replaceObjectAtIndex:0 withObject:dict];
[tableOne reloadData];
In Cell for row at Indexpath
[cell.oneImgView setImage:[[UIImage alloc]initWithData:[dict objectForKey:#"image_four"]]];
I m adding NSMutableDictionary objects into one global array in ViewController A & Sending it to ViewController B where i add/update image from gallery/camera.
but when i press back button and go back UIViewController A and then again go to view controller B those images are still in that array.
In short, whenever i add image to Array of UIViewController B it some how affects to Array of UIViewController A.
I want this to be done on Done button click but if i click on back button of navigation bar it does the same as Done button.
- (IBAction)goToBack:(id)sender {
[self.navigationController popViewControllerAnimated:YES];
}
Can someone tell me where i m going wrong?

Answer 1

Create another array and assign the ViewController array to this array
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
ViewControllerB *controllerb = [segue destinationViewController];
[controllerb setDocuments1:sender];
}
ViewControllerB.h
#property (nonatomic, strong) NSMutableArray *documents1;
ViewController.m
#import "ViewControllerB.h"
#import "UploadCell.h"
#interface ViewControllerB ()
{
NSArray *arrSavedObjects;
}
#end
#implementation ViewControllerB
#synthesize documents,documents1;
-(void)viewWillAppear:(BOOL)animated
{
arrSavedObjects = [[NSUserDefaults standardUserDefaults] objectForKey:#"arrayObjects"];
documents = [NSMutableArray arrayWithArray:arrSavedObjects];
if(documents.count==0)
{
documents = documents1;
}
}
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
UIImage *chosenImage = info[UIImagePickerControllerOriginalImage];
//NSMutableDictionary *dict = [documents objectAtIndex:selected];
NSMutableDictionary *dict = [[NSMutableDictionary alloc] initWithDictionary:[documents objectAtIndex:selected]];
if (![dict objectForKey:#"image1"]) {
[dict setObject:UIImageJPEGRepresentation(chosenImage, 0.5) forKey:#"image1"];
}
else{
[dict setObject:UIImageJPEGRepresentation(chosenImage, 0.5) forKey:#"image2"];
}
[documents removeAllObjects];
[documents addObject:dict];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:documents forKey:#"arrayObjects"];
[defaults synchronize];
[tableDocuments reloadData];
[controller dismissViewControllerAnimated:YES completion:nil];
}

Answer 2

Finally, solved by copying objects of NSObject class & adding it array.
[[controllerb setDocuments1]addObjectsFromArray:array];