How do I 'call' external instance methods?

Question

I want to send a message from a Controller to another Class  to execute a method.  Inside the controller, I typed my message:     
                [[MemoryContent]  PopulateMemory];
What I think I am doing here is telling it to go to the MemoryContent class and execute the method called PopulateMemory.  The compiler insists that I make PopulateMemory into a class method.  But when I do that, I cannot deal with the instance methods and instance variables that I need.  What am I missing?

Answer 1

Assuming you are following recommended Cocoa naming conventions, the fact that MemoryContent has an initial cap means it is a class, not an instance of a class. So the compiler error is correct. If you want to use an instance method, first create an instance of the class, then call the method on the instance.
Your method name PopulateMemory should probably not have an initial cap.
So you would typically see something like this.
MemoryContent *memoryContent = [[MemoryContent alloc] init];
[memoryContent populateMemory];
Of course if the class instance already exists, don't create another one. Instead get a reference to the existing instance.