Question

In my app I am working with the SimpleKML framework

https://github.com/mapbox/Simple-KML

I have some big files which takes about 5 seconds to process thought this library. I was thinking to cache the object in something like NSData.

I have read this tutorial from Apple:

https://developer.apple.com/library/mac/#documentation/cocoa/conceptual/Archiving/Articles/archives.html

But i dont really know of using nscoder is the best way to do this. Can someone point me in the right direction?

Answer 1

You want to use NSKeyedArchiver and NSKeyedUnarchiver.

If the object you’re saving (and the objects it has as properties, and their properties, etc.) implement the NSCoding protocol then it’s, as simple as

NSData *savedData = [NSKeyedArchiver archivedDataWithRootObject:someObject];
[savedData writeToFile:pathToSaveFile atomically:YES];

to archive the object into an NSData and then save it to disk, and then later

NSData *loadedData = [NSData dataWithContentsOfFile:pathToSaveFile];
SomeClass *foo = [NSKeyedUnarchiver loadedData]

to load the data and unarchive the object from the data.

If not, you’ll need to override initWithCoder: and encodeWithCoder: for the objects in question to make them serialize properly.