ios programming - Data argument not used by format string

Question

I get a Data argument not used by format string error when I run the following code:

- (void)pickerView:(UIPickerView *)thePickerView didSelectR         


        

Answer 1

NSLog(@"NSString = ", colour);    
NSLog(@"NSUserDefaults =", [defaults objectForKey:@"colour"]);

Is problematic

Should be

NSLog(@"NSString = %@", colour);
NSLog(@"NSUserDefaults = %@", [defaults objectForKey:@"colour"]);

The format specifier in this case is the %@ which is used to print an object. To print numbers you'd use something like %d. See complete documentation here.

Answer 2

Answer from @debuggerman is absolutely correct. But you can improve your code if you use [defaults setObject:colour forKey:@"colour”]; instead of [defaults setObject:(colour) forKey:@"colour"];

Note that I removed the parentheses for object colour.