Question

I’m trying to use the stringWithString: and stringWithContentsOfFile to save a string to a file and then read it back. It seemed like it should be very simple, but the object return by stringWithContentsOfFile is a null

code

// test strings
NSString *s=[ NSString stringWithString:@"hi"];
[ s writeToFile:@"test.txt" atomically:TRUE];

NSString *g=[ NSString stringWithContentsOfFile:@"test.txt"];

Answer 1

With your code, it will try to save the test.txt file in the root directory, and we can’t have access to the root directory. The only way to save a file is to write it on the application document directory :

NSString *path = [NSString stringWithFormat:@"%@/test.txt", [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]];
[s writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:NULL];