讀外面的檔案

1.m

NSString *path = [[NSBundle mainBundle] pathForResource:@"SleepTypeExplanation"
                                                 ofType:@"rtf"];
NSString *fileContent = [NSString stringWithContentsOfFile:path
                                                  encoding:NSUTF32StringEncoding
                                	             error:&error];

2.m

NSURL *url = [NSURL fileURLWithPath:@"SleepTypeExplanation.rtf"];
NSString *fileContent = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];

handle-error.m

if (fileContent == nil) {
        // an error occurred
        NSLog(@"Error reading file at %@\n%@", path, [error localizedFailureReason]);
}