无法在NSUSerDefault中保存双精度值

Question

Hi everybody :) i want to save a double Value into NSUserDefault like this:

NSUserDefaults *startValues = [NSUserDefaults standardUserDefaults];

[startValues setDouble:[[self.dataList objectAtIndex:indexPath.row]doubleValue] forKey:@"lat"];

[startValues synchronize];

I get no Errors or Warnings from Xcode, but when i run the Code, it crashes with the Message:

-[__NSCFDictionary doubleValue]: unrecognized selector sent to instance

I also tried to split up the Code like:

double lat = [[self.dataList objectAtIndex:indexPath.row]doubleValue];

    [startValues setDouble:lat forKey:@"lat"];

but of course, i get the same error. Whats the Problem?

Thanks for your time and help :)

Answer 1

The problem is that [self.dataList objectAtIndex:indexPath.row] contains a dictionary. NSDictionary does not understand the doubleValue message.

You have to somehow extract the double value from the dictionary:

NSDictionary *dictionary = self.dataList[indexPath.row];
double value = [dictionary[@"latitude"] doubleValue];
[startValues setDouble:value forKey:@"lat"];