将第三方库自定义对象保存到NSUSerDefault

Question

So,I am using the AFPhotoEditorController and there is property of it named as AFPhotoeditorSession that stores and tracks all user action.THis session class is custom object that inherits from NSObject,I have googled about how to save custom objects in NSUser Defaults and came to know that We can save that class if that class conforms to protocol NSCoding ,I don't know that whether I can change this class,Because it is only.h file that I have in my custom framework of AviarySDk.

    NSData *myEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:
   [self.sessions objectAtIndex:0]]; // self.session an array of one object of AFPhotoeditorSession
        NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
        [defaults setObject:myEncodedObject forKey:@"myEncodedObjectKey"];
        [defaults synchronize];
        NSData *data1 = [defaults objectForKey:@"myEncodedObjectKey"];
        AFPhotoEditorSession *obj = (AFPhotoEditorSession *)[NSKeyedUnarchiver unarchiveObjectWithData: data1];
        NSLog(@"%@",obj);

I am getting error like :

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<AFPhotoEditorSession 0x1c5fa0f0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key modified.'

And you can check the AFPhotoEditor Session class at PhotoEditorSession

Answer 1

您可以通过声明并定义一个符合该协议并实现必要方法的类别，使该类符合NSCoding 。

Answer 2

Actually creating your own category means that you will have to have it compliant with that object as new ivars are added or changed, forever.

The right way to do this is to determine exactly what you would need to recreate an object of that class - the core values - then create keys and values for each and put them into a dictionary. Put the dictionaries into your user defaults. When you want to retrieve the values, pull out a dictionary, use those values to instantiate the objects.

The other option is to ask the author of AFPhotoeditor to do it, or do it yourself, and send him a pull request. But if you do it as a add on, you will have to update your category everytime the original framework changes.