Question

I am having an issue with NSDictionary returning null for an NSString even though the string is in the dictionary. Here is the code:

- (void)sourceDidChange:(NSNotification *)aNote {
    NSDictionary *aDict = [aNote userInfo];
    DLog(@"%@", aDict);
    NSString *newSourceString = [aDict objectForKey:@"newSource"];
    DLog(@"%@", newSourceString);
    newSourceString = [newSourceString stringByReplacingOccurrencesOfString:@" " withString:@""];
    DLog(@"%@", newSourceString);
    NSString *inspectorString = [newSourceString stringByAppendingString:@"InspectorController"];
    DLog(@"%@", inspectorString);
    newSourceString = [newSourceString stringByAppendingString:@"ViewController"];
    DLog(@"%@", newSourceString);
}

And I get the following log statements:

2010-04-17 23:50:13.913 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] { newSource = "Second View"; }
2010-04-17 23:50:13.914 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null)
2010-04-17 23:50:13.916 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null)
2010-04-17 23:50:13.917 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null)
2010-04-17 23:50:13.917 CoreDataUISandbox[13417:a0f] -[RightViewController sourceDidChange:] (null)

As you can see, the string is in the dictionary under the key newSource, yet when I call objectForKey:, I get null. I have even tried the fallback option of cleaning the project.

Has anyone ever run into this, or have I just forgotten something really basic?

Answer 1

At this point, you’re left with a reporting error from DLog for some reason.

Try:

1. Logging with NSLog.
2. Check the value of newSourceString directly in the debugger while the code is live.