CODEWITHSUNDEEP
objective-c
CodeHelp
CodeHelp

Reputation: 1328

How to call method in same class

I have a superclass, SuperClassYeh and a subclass, SubClassYeh. I have method inheritTest in SuperClassYeh and I override inheritTest in SubClassYeh. I start the program running by calling method testSuperAndSelf in SubClassYeh. This method would call another method, fromYEH in SuperClassYeh. In fromYEH, I would like to call inheritTest in SuperClassYeh. How do I do that? Using [self inheritTest] calls the inheritTest in SubClassYeh, not SuperClassYeh.

Here's the code fragment to start the whole thing running

SubClassYeh *testing = [[SubClassYeh alloc] init];
[testing testSuperAndSelf];

Here's the code fragment for SuperClassYeh

- (void) fromYEH
{
    [self inheritTest]; //Calls the inheritTest in SubClassYeh, not SuperClassYeh
}

- (void) inheritTest
{
    NSLog(@"Testing Indicator. Inside SuperClassYEH inheritTest");
}

Here's the code fragment for SubClassYeh

- (void) inheritTest
{
    NSLog(@"Testing Indicator. Inside SubClassYeh inheritTest");
}

- (void) testSuperAndSelf
{
    [super fromYEH];  
}

Upvotes: 0

Views: 1005

Answers (5)

techniao
techniao

Reputation: 151

Just for the record...

What you want to do isn't as difficult as you think, if you look at it from a different perspective.

All you have to do is define a C function and call that.

- (void) fromYEH
{
    inheritTest(self); //Calls the inheritTest() in SuperClassYeh
}

void inheritTest(SuperClassYeh *self)
{
    NSLog(@"Testing Indicator. Inside SuperClassYEH inheritTest");
}    

- (void) inheritTest
{
    inheritTest(self);
}

(I love the names... ;)

Upvotes: 0

CodeHelp
CodeHelp

Reputation: 1328

I found the solution. Instead of calling [super fromYeh]in testSuperAndSelf, change the receiver to the superclass. Use [[[[SubClassYeh superclass] alloc] init] fromYEH]. Inside method fromYEH, the inheritTest of SuperClassYEH would be called.
Here is the code fragment for method testSuperAndSelf in SubClassYeh. Other codes remain the same.

- (void) testSuperAndSelf
{
    [[[[SubClassYeh superclass] alloc] init] fromYEH];  
}

Upvotes: 0

Morion
Morion

Reputation: 10860

Even it is a quite strange behavior, you can try something like this(didn't test it, actually)

- (void) fromYEH
{
    bool isSubClass = [self isKindOfClass:[SubClassYeh class]];
    if(isSubClass == YES)
    {
        [super performSelector:@selector(inheritTest)];
    }
    else
    {
        [self inheritTest];
    }
}

Anyway, even if this code will really do the trick, I still think that this is very bad practice.

EDIT:

Checked this in XCode. It will not do the trick =) So upvoted Martin's answer =)

Upvotes: 0

Martin R
Martin R

Reputation: 539685

You can't, and this is the intended behaviour of inheritance in Objective-C.

If self is an instance of SubClassYeh, then

[self inheritTest]

calls the SubClassYeh implementation of inheritTest (if there is one), no matter from where that message is sent (subclass or superclass).

The only difference between [super fromYEH] and [self fromYEH] is that the lookup for the "fromYEH" message starts at the superclass, but it does not change the fact that self is an instance of SubClassYeh.

And you cannot prevent a method from being overriden in Objective-C (see How to avoid superclass methods getting overridden by sub class in objective - c or other Q&A's about that topic).

The only thing that you can do in the superclass is to choose method names that are not overriden accidentally, e.g. by prefixing the method name with the class name, as suggested here: https://stackoverflow.com/a/17209309/1187415.

Upvotes: 5

thatzprem
thatzprem

Reputation: 4767

If you can call [super fromYEH] from SubClassYeh, what is the problem in calling [super inheritTest] the same way?

Upvotes: 0

Related Questions