saving udid string to a text file - ios

Question

hi i'm working on a simple activation app in iOS. i want to save udid in a text file and equal text file with current udid but i can't save udid to text file
NSString *udid = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
NSURL *fileURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:#"h" ofType:#"txt"]];
NSMutableString *text = [NSMutableString stringWithContentsOfURL:fileURL encoding:NSUTF8StringEncoding error:nil];
NSLog(#"text is : %#",text);
NSString *text1 = text;
NSString *y;
if ([text1 isEqualToString:y]) {
[text appendString:udid];
NSString *myURLString = [fileURL absoluteString];
[text writeToFile:myURLString atomically: YES encoding:NSUTF8StringEncoding error:nil];
NSLog(#"saved to file : %#",text);
}else {
if ([text isEqualToString:udid]) {
NSLog(#"yes thats it");
lable.text = #"yes thats it";
}else {
NSLog(#"nononono");
exit(0);
}
}

Answer 1

There's a few problems with your code. Starting with:
if ([text1 isEqualToString:y]) {
where is "y" defined or declared?
Also, you never look at the error parameter while writing to a file. Change this:
[text writeToFile:myURLString atomically: YES encoding:NSUTF8StringEncoding error:nil];
to this:
NSError *error;
BOOL success = [text writeToFile:myURLString atomically: YES encoding:NSUTF8StringEncoding error:&error];
if(NO == success)
{
NSLog(#"error from writing to %# is %#", myURLString, [error localizedDescription]);
}
And you might have a better clue as to what kind of error you're running into.
Lastly, with your comment, you've made it clear you're trying to write a file directly into the bundle of your application. Which is a big (sandboxed) no no.
Instead of:
NSURL *fileURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:#"h" ofType:#"txt"]];
do this instead:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *basePath = [paths firstObject];
NSURL *fileURL = [NSURL fileURLWithPath:[basePath stringByAppendingString:#"/h.txt"]];
and this will save your file into the Documents directory, which is a legal place to save files.