Reading and Writing plists

Reading a plist file from the application bundle just requires a few lines of code, and some error handling. I like to place that code in a nice convenience method like this:
 

- (id)readPlist:(NSString *)fileName {
   NSData *plistData;
   NSString *error;
   NSPropertyListFormat format;
   id plist;

   NSString *localizedPath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"plist"];
   plistData = [NSData dataWithContentsOfFile:localizedPath];
   plist = [NSPropertyListSerialization propertyListFromData:plistData mutabilityOption:NSPropertyListImmutable format:&format errorDescription:&error];
   if (!plist) {
      NSLog(@"Error reading plist from file '%s', error = '%s'", [localizedPath UTF8String], [error UTF8String]);
      [error release];
   }

   return plist;
}

I’m not too fond of using id as return values or parameters to methods. I prefer stronger type checks, so I typically wrap the readPlist method in two methods that return either an array or a dictionary.



- (NSArray *)getArray:(NSString *)fileName {
   return (NSArray *)[self readPlist:fileName];
}

- (NSDictionary *)getDictionary:(NSString *)fileName {
   return (NSDictionary *)[self readPlist:fileName];
}

Writing to a plist file is not much more difficult:

- (void)writePlist:(id)plist fileName:(NSString *)fileName {
   NSData *xmlData;
   NSString *error;

   NSString *localizedPath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"plist"];
   xmlData = [NSPropertyListSerialization dataFromPropertyList:plist format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
   if (xmlData) {
      [xmlData writeToFile:localizedPath atomically:YES];
   } else {
      NSLog(@"Error writing plist to file '%s', error = '%s'", [localizedPath UTF8String], [error UTF8String]);
      [error release];
   }
}