Increment Number in plist - iphone

Question

I am using the method below to get an array from my plist and then increase a certain value by 1, then save it. However I log the array and the value doesn't actually go up each time.
In my plist, I have an array and in that number values, each one is set to 0. So every time I run this again it goes back to 0 it seems.
NSString *path = [[NSBundle mainBundle] bundlePath];
NSString *finalPath = [path stringByAppendingPathComponent:#"Words.plist"];
NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithContentsOfFile:finalPath];
NSMutableArray *errors = [dict objectForKey:[NSString stringWithFormat:#"Errors%d.%d", [[stageSelectionTable indexPathForSelectedRow] section] +1, [[stageSelectionTable indexPathForSelectedRow] row] +1]];
int a = [[errors objectAtIndex:wordIndexPath] intValue];
a += 1;
NSNumber *b = [NSNumber numberWithInt:a];
[errors replaceObjectAtIndex:wordIndexPath withObject:b];
[errors writeToFile:finalPath atomically:YES];

Answer 1

You can only write to a file in the documents-folder. You can't write to your bundle!
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:#"Namelist.plist"];
You can use NSFilemanager to copy your Plist-File to the documents-folder.
To get the path of your file:
- (NSString *)filePath {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:#"MyFile.plist"];
return filePath;
}
To copy the file if it doesn't exist:
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath:[self filePath]]) {
NSString *path = [[NSBundle mainBundle] pathForResource:#"MyFile" ofType:#"plist"];
[fileManager copyItemAtPath:path toPath:[self filePath] error:nil];
}
Now you can write your NSDictionary to the Documents-Directory:
[dict writeToFile:[self filePath] atomically:YES];
But you really need to update the array in the dict!

Answer 2

You are writing the array to disk, instead of the dictionary that the array originated from:
[dict writeToFile:finalPath atomically:YES];
Also, you will need to replace the Errors%d.%d object with the updated one before saving it:
[dict setObject:errors forKey:/* your formatted key*/];
Finally, as #mavrick3 pointed out, you cannot save files to your bundle, only to your application's documents directory.