writeToFile:atomically: not saving new plist data - ios

Question

I am using writeToFile:atomically: to update the value of a key in my plist by 1 every time the app is launched. I put this code in viewDidLoad, which reads the string value of the key, gets the numeric value of that string, increases it by 1, converts it back to a string, and writes that as the new string for that key, but when I read it again it seems to have not updated. I can't figure out what I'm doing wrong. I don't need a special framework for writeToFile:atomically:, do I?
Here is the code:
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"DaysLaunched.plist"];
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath: path])
{
NSString *bundle = [[NSBundle mainBundle] pathForResource:#"DaysLaunched" ofType:#"plist"];
[fileManager copyItemAtPath:bundle toPath:path error:&error];
}
NSMutableDictionary *plistDict = [[NSMutableDictionary alloc] initWithContentsOfFile: path];
NSMutableDictionary *data1 = [[NSMutableDictionary alloc] initWithContentsOfFile: path];
NSString *currentNumberOfDays = [NSString stringWithFormat:#"%#",[plistDict objectForKey:#"numberOfDays"]];
NSLog(#"currentNumberOfDays = %#", currentNumberOfDays); //0
int days = [currentNumberOfDays intValue];
days ++;
currentNumberOfDays = [NSString stringWithFormat:#"%d", days];
[data1 setObject:[NSString stringWithFormat:#"numberOfDays"] forKey:currentNumberOfDays];
NSLog(#"currentNumberOfDays = %#", currentNumberOfDays); //1
[data1 writeToFile: path atomically:YES];
currentNumberOfDays = [NSString stringWithFormat:#"%#",[plistDict objectForKey:#"numberOfDays"]];
NSLog(#"currentNumberOfDays = %#", currentNumberOfDays); //0 ??????? writeToFile isn't working?
And here is a screenshot of "DaysLaunched.plist" in my 'Supporting Files' folder, (I've also verified that the plist file name is spelled exactly the same way I spelled it in my code, via Copy-Paste)
The original plist file is also in my 'Copy Bundle Resources' in targets.

Answer 1

Try
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"DaysLaunched.plist"];
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager fileExistsAtPath: path])
{
NSString *bundle = [[NSBundle mainBundle] pathForResource:#"DaysLaunched"
ofType:#"plist"];
[fileManager copyItemAtPath:bundle toPath:path error:&error];
}
NSMutableDictionary *plistDict = [NSMutableDictionary dictionaryWithContentsOfFile:path];
NSInteger days = [plistDict[#"numberOfDays"] integerValue];
plistDict[#"numberOfDays"] = [#(++days) stringValue];
[plistDict writeToFile: path atomically:YES];

Answer 2

You have made a mistake while setting your data.
You should do:
[data1 setObject:currentNumberOfDays forKey:#"numberOfDays"];
instead of:
[data1 setObject:[NSString stringWithFormat:#"numberOfDays"] forKey:currentNumberOfDays];