Can I write an array of UILocalNotifications to disk? - iphone

Question

I'm trying to use the following code to persist the current list of local notifications. NSArray explicitly lists the kind of objects it will work with, which implies I can not use this with an array full of UILocalNotification objects. However, UILocalNotifications does implement NSCoding, which led me to believe there must be an easy way to serialize/deserialize this list of objects. Do I need to do the encoding and file persistence myself? Also, is there a way to get more information about why the write failed?
- (NSString*)getSavedNotifsPath {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
return [documentsDirectory stringByAppendingString:#"saved_notifs.plist"];
}
- (void)prepareToHide {
UIApplication* app = [UIApplication sharedApplication];
NSArray *existingNotifications = [app scheduledLocalNotifications];
if (! [existingNotifications writeToFile:[self getSavedNotifsPath] atomically:NO] ) {
// alert
[self showSomething:#"write failed"];
}
}

Answer 1

First, change the code
return [documentsDirectory stringByAppendingString:#"saved_notifs.plist"];
to
return [documentsDirectory stringByAppendingPathComponent:#"saved_notifs.plist"];
stringByAppendingPathComponent: will ensure a slash (/) is included, if needed, before the file name.
NSArray can only save property list objects, which UILocalNotification is not. Instead, try using NSKeyedArchiver. For example:
- (void)prepareToHide {
UIApplication* app = [UIApplication sharedApplication];
NSArray *existingNotifications = [app scheduledLocalNotifications];
NSString *path = [self getSavedNotifsPath];
BOOL success = [NSKeyedArchiver archiveRootObject:existingNotifications toFile:path];
if (! success ) {
// alert
[self showSomething:#"write failed"];
}
}
Use NSKeyedUnarchiver to retrieve the array from the saved file.
Note: I have not actually tested this so I'm not 100% sure it will work. But give it a try and see what happens.