CODEWITHSUNDEEP
objective-c
muttley91
muttley91

Reputation: 12674

Invalid Selector on doubleValue

A bit new to Objective-C, so please bear with me.

Firstly, I'm using the FMDB library for SQLite management.

I'm populating an NSMutableDictionary using the following method:

//....
while([effectivenessResults next]) //this loops through the results of a query (verified that this works)
    {
        NSMutableArray *dFactors = [[NSMutableArray alloc]init];
        if([resultDict objectForKey:[effectivenessResults stringForColumn:@"tName"]])
        {
            dFactors = [resultDict objectForKey:[effectivenessResults stringForColumn:@"tName"]];
        }
        NSNumber *effectivenessValToAdd = [NSNumber numberWithDouble:[effectivenessResults doubleForColumn:@"dFactor"]/100];
        [dFactors addObject:[NSMutableString stringWithFormat:@"%@",effectivenessValToAdd]];
        [resultDict setObject:dFactors forKey:[effectivenessResults stringForColumn:@"tName"]];
    }

I'm returning the array properly (I have verified this). Then, I am accessing this NSMutableDictionary elsewhere, using the follwing method:

for(id type in tEffect) //tEffect is the NSMutableDictionary, returned from the previous code (there known as resultDict)
{
    effectivenessString = [self getEffectivenessString:[tEffect objectForKey:type]];

    tInfo = [NSMutableString stringWithFormat:@"%@", [tInfo stringByAppendingFormat:@"%@: %@\n", type, effectivenessString]];

}

which calls the following two methods:

-(NSMutableString *)getEffectivenessString:(NSNumber *) numberPassedIn
{
    double dFactor = [numberPassedIn doubleValue];
    //adds the above value to a string, this will not affect anything
}

and

-(NSNumber *) listProduct: (NSMutableArray *)listOfValues //calculates the product of an NSMutableArray of numbers
{
NSNumber *product=[NSNumber numberWithDouble:1.0];

for(int i = 0; i < [listOfValues count]; i++)
{
    NSNumber *newVal = [listOfValues objectAtIndex:i];
    product = [NSNumber numberWithDouble:[product doubleValue] * [newVal doubleValue]];
}
return product;
}

So, when I call these methods, I am getting the following error:

2013-08-04 13:52:04.514 effectCalculator[45573:c07] -[__NSArrayM doubleValue]:              
unrecognized selector sent to instance 0x8c19e00
2013-08-04 13:52:04.521 effectCalculator[45573:c07] *** Terminating app due to uncaught     
exception 'NSInvalidArgumentException', reason: '-[__NSArrayM doubleValue]: unrecognized 
selector sent to instance 0x8c19e00'

Important to note: This error occurs on the retrieval, NOT the populating of the NSMutableDictionary. This means the population of this dictionary not the an issue, but it might have something to do with why it's having trouble retrieving the data.

So what might cause this error?

Upvotes: 0

Views: 165

Answers (1)

Dave
Dave

Reputation: 46329

Your code is pretty difficult to follow. In future please post a minimal sample which compiles, or at least is a single block of understandable code.

Having said that, I believe your issue is with this bit:

for(id type in tEffect) //tEffect is the NSMutableDictionary, returned from the previous code (there known as resultDict)
{
    effectivenessString = [self getEffectivenessString:[tEffect objectForKey:type]];

what does resultDict contain?

[resultDict setObject:dFactors ...

but dFactors is an NSMutableArray. Well getEffectivenessString expects a NSNumber, not a NSMutableArray. So it complains. Also I think you intended for the method to take a string, not a number, although I don't see why you're not casting as you load them (instead of as you use them).

Since Objective C doesn't support strongly-typed arrays or dictionaries, your best bet to defend against this in the future is to name your variables more logically. It should stand out when you try to call a method which expects a number with an array instead.

Upvotes: 2

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