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how to create an "array of selectors' in objective-c

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By User


i'm using the iphone sdk (3.0) and i'm trying to create an array of selectors to invoke a variety of methods within one class.



Obviously, I'm doing something wrong (I think @selector isn't considered a class and so stuffing them into an NSArray isn't working).



I tried this, but it's obviously wrong.



Is there a simple way to have an array of selectors like this? Or is there a better way to iterate through a collection of methods?



Thanks for any insight!! 





selectors = [NSArray arrayWithObjects:

                          @selector(method1),

                          @selector(method2),

                          @selector(method3),

                          @selector(method4),

                          @selector(method5),

                          @selector(method6),

                          @selector(method7), nil];



for (int i = 0; i < [selectors count]; i++) {

  if ([self performSelector:[selectors objectAtIndex:i]]) // do stuff;

}

Source: Tips4all, CCNA FINAL EXAM
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Comments

  1. UserMay 19, 2012 at 2:53 AM

    Could you store strings and use NSSelectorFromString?

    From the docs

    NSSelectorFromString


    Returns the selector with a given name.

    SEL NSSelectorFromString (
    NSString *aSelectorName
    );

    ReplyDelete
  2. UserMay 19, 2012 at 2:53 AM

    This creates an object out of selector:

    [NSValue valueWithPointer:@selector(x)]

    ReplyDelete
  3. UserMay 19, 2012 at 2:53 AM

    Why not just use a simple C array?

    static const SEL selectors[] = {@selector(method1),
    ....
    @selector(method7)};

    ...

    for (int i = 0; i < sizeof(selectors)/sizeof(selectors[0]); i++) {
    [self performSelector:selectors[i]];
    // ....
    }

    ReplyDelete
  4. UserMay 19, 2012 at 2:53 AM

    You can also create an array of NSInvocations. This is handy if you need an argument to go with your selector.

    NSMethodSignature *sig = [[yourTarget class] instanceMethodSignatureForSelector:yourSEL];
    NSInvocation *inv = [NSInvocation invocationWithMethodSignature:sig];
    [inv setTarget:yourTarget];
    [inv setSelector:yourSEL];
    [inv setArgument:&yourObject atIndex:2]; // Address of your object

    ReplyDelete

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