Question

I’m using a property-file with this structure:

maxRating     Number    --> 5
gradePercent  Dictonary
>grade1       Number    --> 0.85
>grade2       Number    --> 0.70
>grade3       Number    --> 0.55
>grade4       Number    --> 0.40

To read the properties I’m using

NSDictionary *plist = [[NSDictionary alloc] initWithContentsOfFile:filepath];

rating = [[plist objectForKey:@"maxRating"] intValue];
gradePercent = (NSMutableDictionary*)[[plist objectForKey:@"gradePercent"] copy];

Till here every thing works perfectly…I can get the right objects with [gradePercent objectForKey:@"grade1"]

but when I try to set one of them with

[gradePercent setObject:[NSNumber numberWithFloat:0.90] forKey:@"grade1"]

I always get a SIGABRT error and the APP is crashing.

Does anyone see why this isn’t working? Because I don’t -.-

Answer 1

An NSDictionary is immutable, and simply casting the pointer to NSMutableDictionary * doesn’t make the object magically become mutable. So you need a mutable dictionary. You could do it like this:

NSMutableDictionary *plist = [[NSMutableDictionary alloc] initWithContentsOfFile:filepath];