How to convert binary data to NSData - iphone

Question

I have converted the UIImageview into NSData and stored it as binary data. but i don't know how to retrieve the binary data to NSData and convert that to UIImageview
my code is below
image save as binary data----
-(void) save
{
UIImage *img = [UIImage imageNamed:#"back2.png"];
NSData *dataObj =UIImagePNGRepresentation(img);
NotesDetails *notesDetails = (NotesDetails *) [NSEntityDescription insertNewObjectForEntityForName:#"NotesDetails" inManagedObjectContext:managedObjectContext];
notesDetails.imageData=dataObj;
NSLog(#"NotesDetails: %#",notesDetails);
NSError *error;
if (![managedObjectContext save:&error])
{
}
}
Image Retreive------
-(void)viewDidLoad
{
NSFetchRequest *fectchreq = [[NSFetchRequest alloc] init];
NSEntityDescription *entitydes = [NSEntityDescription entityForName:#"NotesDetails"
inManagedObjectContext:self.managedObjectContext];
[fectchreq setEntity:entitydes];
NSSortDescriptor *sortdes = [[NSSortDescriptor alloc] initWithKey:#"notesTime" ascending:YES];
NSArray *sortdesarray = [[NSArray alloc] initWithObjects:sortdes, nil];
[fectchreq setSortDescriptors:sortdesarray];
NSError *error;
NSMutableArray *storeddata = [[self.managedObjectContext executeFetchRequest:fectchreq error:&error] mutableCopy];
if ([storeddata count] > 0)
{
for (NotesDetails *sc in storeddata)
{
imgFromDb=[NSData dataWithData:[#"%#",sc.imageData]];
}
}
NSLog(#"Image : %#",imgFromDb);
UIImageView *dbImage=[[UIImageView alloc]initWithFrame:CGRectMake(80,20,90,90)];
dbImage.image=[UIImage imageWithData:imgFromDb];
[NoteDetails addSubview:dbImage];
}

Answer 1

You can use NSKeyedUnarchiver:
imgFromDb= [NSKeyedUnarchiver unarchiveObjectWithData: sc.imageData];
And you can do the opposite (object to data) with NSKeyedArchiver if you prefer it vs UIImagePNGRepresentation().
And there are other ways to do this, for example:
imgFromDb= [UIImage imageWithData: sc.imageData];