Question

I have an application that has an area that is supposed to behave somewhat like a photo gallery. The user chooses a picture from their camera roll, and the photos get displayed in UIImageViews. I’m trying to save the image that they select. I have 9 UIImageView’s, and the issue is that when I select a different photo for each UIImageView, close and relaunch the app, all of the UIImageViews are blank. Here is the code that I’m working with:

- (void)viewWillAppear:(BOOL)animated
{

    self.user = [NSUserDefaults standardUserDefaults];

    NSMutableArray* array = [[self.user objectForKey:@"images"]mutableCopy];
    while(array == nil)
    {
        [self.user setObject:[NSMutableArray arrayWithObject:@""] forKey:@"images"];
        array = [[self.user objectForKey:@"images"]mutableCopy];
        NSLog(@"%@",@"attempting to create an array to store the images in");
    }

}

- (void)applicationDidEnterBackground:(UIApplication*)application {
    NSLog(@"Image on didenterbackground: %@", imageView);
    NSMutableArray* array = [NSMutableArray arrayWithObject:[NSData dataWithData:UIImagePNGRepresentation(imageView.image)]];

    [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView2.image)]];
     [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView3.image)]];
      [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView4.image)]];
       [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView5.image)]];
        [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView6.image)]];
         [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView7.image)]];
          [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView8.image)]];
           [array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView9.image)]];

            [self.user setObject:array forKey:@"images"];

            }

- (void)viewDidLoad
    {
        NSMutableArray* array = [[self.user objectForKey:@"images"]mutableCopy];
        imageView.image = [[UIImage alloc] initWithData:[array objectAtIndex:0]];
        imageView2.image = [[UIImage alloc] initWithData:[array objectAtIndex:1]];
        imageView3.image = [[UIImage alloc] initWithData:[array objectAtIndex:2]];
        imageView4.image = [[UIImage alloc] initWithData:[array objectAtIndex:3]];
        imageView5.image = [[UIImage alloc] initWithData:[array objectAtIndex:4]];
        imageView6.image = [[UIImage alloc] initWithData:[array objectAtIndex:5]];
        imageView7.image = [[UIImage alloc] initWithData:[array objectAtIndex:6]];
        imageView8.image = [[UIImage alloc] initWithData:[array objectAtIndex:7]];
        imageView9.image = [[UIImage alloc] initWithData:[array objectAtIndex:8]];



        UIApplication *app = [UIApplication sharedApplication];
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(applicationDidEnterBackground:)
                                                     name:UIApplicationDidEnterBackgroundNotification
                                                   object:app];


        [super viewDidLoad];

    }

- (void)viewDidUnload
    {
        self.user = nil;
    }

Everything looks okay to me, so I can’t figure out why they are not saving / loading. Any help is much appreciated, thanks!

Answer 1

You assign self.user in viewWillAppear which is called after viewDidLoad.

You should change viewDidLoad to:

-(void)viewDidLoad {
  self.user = [NSUserDefaults standardUserDefaults];
  // ... rest the same