Question

I installed everything according to README file and imported all necessary libraries. Still, when implementing this method:

- (CPTLayer *)dataLabelForPlot:(CPTPlot *)plot recordIndex:(NSUInteger)index {
    CPTMutableTextStyle *labelText = nil;
    labelText= [[CPTMutableTextStyle alloc] init];
    labelText.color = [CPTColor grayColor];

    return [[CPTTextLayer alloc] initWithText:@"Test" style:labelText];
}

I receive errors:

ARC Semantic issue - Receiver 'CPTTextLayer' for class message is a forward declaration
and
ARC Semantic issue - Receiver 'CPTTextLayer' for instance message is a forward declaration

I read in many posts, that this is the fault of missing Quartz library, though I have it imported in the project and included in the class: #import <QuartzCore/QuartzCore.h>.

When I return nil instead of this, everything works, but hey, I need those data labels to work!

Anybody knows how to make it work?

Answer 1

Normally forward class error comes when that particular class is not imported in the current class and an @class is declared in .h file. If @class is also not present, it normally gives an unknown type error. So in this case as mentioned in comments, it is clear that the import statement for CPTTextLayer is missing.