Trying to create and write to file using NSFileHandle... and it doesn't seem to be working

Question

What am I doing wrong here:

NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; 
self.gpsFilePath = [documentsDirectory stringByAppendingString: @"/gpsReadings.txt"];
self.gpsFile = [NSFileHandle fileHandleForWritingAtPath:self.gpsFilePath];
[self.gpsFile writeData:@"GPS Readings"];
[self.gpsFile closeFile];

Answer 1

I need to create the file first:

[[NSFileManager defaultManager] createFileAtPath:self.gpsFilePath contents:nil attributes:nil];