Question

I have a function that checks whether the plist exists or not, if not it will create the plist.

this function is called in background i.e
[self performSelectorInBackground:@selector(CreatePlist:) withObject:xyz];

everything goes just perfect.

but when i try to fetch the data from the plist on main thread i.e

NSString *path = [[NSBundle mainBundle] pathForResource:@"calendar" ofType:@"plist"];
NSLog(@"path is %@", path); // path comes null
fileName = [fileName stringByReplacingOccurrencesOfString:@"/" withString:@""];
NSLog(@"file name data contain %@",fileName);
NSFileManager *fileManager = [NSFileManager defaultManager];

//see if Data.plist exists in the Documents directory
if (![fileManager fileExistsAtPath:[self saveMyPath:fileName] ]) {
    [fileManager copyItemAtPath:path toPath:[self saveMyPath:@""] error:nil]; //at this point the app crashes saying path is null
}

when i moved my application from the background to the main thread it works well.
what is the problem here.?

Answer 1

looks like the background thread isn’t finished when the main thread gets to it.

you could try using grand central dispatch.. e.g.

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
  [self CreatePlist:xyz];
  dispatch_async(dispatch_get_main_queue(), ^{
    NSString *path = [[NSBundle mainBundle] pathForResource:@"calendar" ofType:@"plist"];
    NSLog(@"path is %@", path); // path comes null
    fileName = [fileName stringByReplacingOccurrencesOfString:@"/" withString:@""];
    NSLog(@"file name data contain %@",fileName);
    NSFileManager *fileManager = [NSFileManager defaultManager];

    //see if Data.plist exists in the Documents directory
    if (![fileManager fileExistsAtPath:[self saveMyPath:fileName] ]) {
       [fileManager copyItemAtPath:path toPath:[self saveMyPath:@""] error:nil]; //at this point the app crashes saying path is null
  });
});