Objective-C basics: subclassing and member variable accessability

Posted by Krumelur on Stack Overflow See other posts from Stack Overflow or by Krumelur
Published on 2010-05-19T14:19:56Z Indexed on 2010/05/19 14:20 UTC
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Hi,

Code below is pseudo code. Imagine a class "Fruit" which has a factory method to create a fruit.

interface Fruit
{
}
+(Fruit*) createFruit:
{
  return [[Fruit alloc] init autorelease];
}

Now I want to subclass the Fruit to get an Apple:

interface Apple : Fruit
{
int iSeeds;
}
+(Apple*) createAppleWithColor: (int) iSeeds
{
Apple* oApple = [Apple createFruit:];
oApple.iSeeds = iSeeds;
return oApple;
}

Questions:

  • How can I make "iSeeds" private so it cannot be changed from outside? If I add a "private" keyword it does not build anymore.
  • Still I want to set iSeeds from inside my Apple's factory method.
  • I want users allow to READ the content of iSeeds. So I suppose I should have a getter but I can't get it to work. I always get some error about "LValue assignment".
  • The Fruit's createFruit is making use of autorelease. Does the Apple have to reatin/release anything?

René

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