是否可以使用NSKeyedArchiver存储动画的UIImage？

Question

I loaded an image using frames downloaded from a web server.

NSArray* frames = [self fetchFramesFromServer];
imageView.image = [UIImage animatedImageWithImages:frames duration:1.0];

Whenever I try to archive these frames, the encoding function returns NO:

BOOL success = [NSKeyedArchiver archiveRootObject:(frames) toFile:archivePath];

Whenever I try to archive the image, the encoding function also returns NO:

BOOL success = [NSKeyedArchiver archiveRootObject:(imageView.image) toFile:archivePath];

Is this even possible, or am I missing some caveat of archiveRootObject that requires the UIImage to be loaded from the bundle, in png-format, or non-animated?

Just FYI, the archivePath when printed out in the debugger is

NSPathStore2 * @"/var/mobile/Containers/Data/Application/E475E3C1-4E3F-43D6-AD66-0F98320CF279/Library/Private Documents/assets/a/b/c.archive"   0x000000012c555a60

UPDATE:

I am storing the individual frames of the animation inside a for-loop, but I get the following:

+ (void) saveImage:(UIImage*)inputImage
    withSuffix:(NSString*)fileSuffix
{
if (inputImage == nil) {
    NSLog(@"ERROR: input image is nil!");
    return;
}

// strip away intermediate folders to avoid over-nesting
// ex: __F1/MF/FR/1_MF_FR_Animation_a1.png
// ===> 1_MF_FR_Animation_a1.png
NSString* suffixStub = [MyDatabase stubOfFilepath:fileSuffix];

NSURL* url = [MyDatabase folderURL];
NSURL* imageURL = [url URLByAppendingPathComponent:suffixStub];

NSData* pngData = UIImagePNGRepresentation(inputImage);
[NSKeyedArchiver archiveRootObject:pngData toFile:imageURL.path];
pngData = nil;

NSLog(@"Image %@ successfully saved!", fileSuffix);
} 

But on the NSKeyedArchiver line, I get "malloc: *** error for object 0x178202340: Freeing unallocated pointer"

Answer 1

First convert your image to NSData and then try archiving it

NSData* data = UIImagePNGRepresentation(imageView.image);
BOOL success = [NSKeyedArchiver archiveRootObject:data toFile:archivePath];

In case of NSArray , archiving is possible only if all the objects of array conforms to NSCoding protocol. If your array has custom object refer Custom object archiving on how to conform to NSCoding .

UPDATE

If objects of your array are frames of type CGRect the you can use NSStringFromCGRect() and CGRectFromString() to store and then retrieve them.