Question

When the user starts the app for the first time he gets a pop up and has to save an image. It works on the simulator and on the 4S. But when I start it with my 3G it gives me a SIGABRT error as soon as I chose a picture. I assume its because of the size of the picture which is too pick and therefore claiming all of the ram – But that is rather weird, because I make it much smaller. Here is the code:

- (void)viewDidLoad
{ 
    [super viewDidLoad];
    if ([[NSUserDefaults standardUserDefaults] objectForKey:@"bild"] == nil) { 
        picker = [[UIImagePickerController alloc] init];
        picker.delegate = self;
        picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        [self presentModalViewController:picker animated:YES];
    }
}

- (void)imagePickerController:(UIImagePickerController *) Picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    double compressionRatio=1;
    NSData *imageData=UIImageJPEGRepresentation([info objectForKey:@"bild"],compressionRatio);
    while ([imageData length]>5000) { 
        compressionRatio=compressionRatio*0.20;
        imageData=UIImageJPEGRepresentation([info objectForKey:@"bild"],compressionRatio);
    }

    UIImage *yourUIImage;
    yourUIImage = [info objectForKey:UIImagePickerControllerOriginalImage];
    imageData = [NSKeyedArchiver archivedDataWithRootObject:yourUIImage];
    [[NSUserDefaults standardUserDefaults] setObject:imageData forKey:@"bild"];
    [[NSUserDefaults standardUserDefaults] synchronize];

    [self dismissModalViewControllerAnimated:YES];
}

I get the SIGABRT error at this line imageData = [NSKeyedArchiver archivedDataWithRootObject:yourUIImage];

Should I use another method to resize the image? Or should I save it as a local file and retrieve it everytime the app starts? (If its possible)

Answer 1

You are using NSCoding to archive an UIImage into a NSData object.
Before iOS5 UIImage didn’t implement the methods for NSCoding. You simply can’t use archivedDataWithRootObject: with UIImages before iOS5.
That’s why you get an exception on the iPhone 3G.

This is just a very educated guess because I can’t confirm that with documentation or a test on a device but there are a lot of questions and forum posts around that ask how to implement NSCoding on UIImage.

---

and this whole block of code isn’t called at all because [info objectForKey:@"bild"] will return nil. The info dictionary does not contain an object for the key bild.
Documentation for UIImagePickerControllerDelegate_Protocol contains a List of valid keys

NSData *imageData=UIImageJPEGRepresentation([info objectForKey:@"bild"],compressionRatio);
while ([imageData length]>5000) { 
    compressionRatio=compressionRatio*0.20;
    imageData=UIImageJPEGRepresentation([info objectForKey:@"bild"],compressionRatio);
}

---

you probably want to use something like that:

NSData *data;
if ([[UIImage class] conformsToProtocol:@protocol(NSCoding)]) {
    // >= iOS5
    data = [NSKeyedArchiver archivedDataWithRootObject:image];
    // save so you know it's an archived UIImage object
}
else {
    // < iOS5
    data = /* your UIImageJPEGRepresentation method but this time with the key UIImagePickerControllerOriginalImage instead of "bild" */
    // save so you know it's raw JPEG data
}