Error when trying to save indexPath to NSUserDefau

问题:

I am trying to save the indexPath for UICollectionView, but I get the following error:

libc++abi.dylib: terminating with uncaught exception of type NSException

My code is: Save index path:

[[NSUserDefaults standardUserDefaults] setObject:indexPath forKey:@"CollectionIndex"];
[[NSUserDefaults standardUserDefaults] synchronize];

Load indexPath:

NSIndexPath *storedIndexPath = [[NSUserDefaults standardUserDefaults] objectForKey:@"CollectionIndex"];

I have commented out code to find out which code that makes the error, and it is the code I am using to save the indexPath that creates the SIGABRT error.

回答1:

Read the documentation of NSUserDefaults > setObjectForKey:

"The value parameter can be only property list objects: NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. For NSArray and NSDictionary objects, their contents must be property list objects. See “What is a Property List?” in Property List Programming Guide."

To save an indexPath in the UserDefaults, you would have to make another representation, e.g. as a dictionary:

[[NSUserDefaults standardUserDefaults] setObject:@{@"row": @(indexPath.row),
                                                   @"section": @(indexPath.section)}
                                          forKey:@"CollectionIndex"];