How to pass elements of an array to variadic function?

I'm sure this must be answered somewhere already but I'm struggling to find the right search terms for the answer.

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In my objective-c code I have an NSArray of an unknown number strings that I want to pass its elements to a variadic init method, in this case its the ... list of 'otherButtonTitles' in the constructer of UIActionSheet. How can this be achieved?

thanks in advance

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I think you would need to pass the first element of the array to the constructor and then use the addButtonWithTitle method to loop through the remaining elements and add them:

UIActionSheet *mySheet = [[UIActionSheet alloc] initWithTitle:title delegate:delegate cancelButtonTitle:cancelButtonTitle destructiveButtonTitle:destructiveButtonTitle otherButtonTitles:[myOtherButtons objectAtIndex:0],nil];

NSMutableArray *otherbuttons = myOtherButtons;
[otherButtons removeObjectAtIndex:0];

NSEnumerator *enumerator = [otherButtons objectEnumerator];
id anObject;

while (title = [enumerator nextObject]) {
    [mySheet addButtonWithTitle:title];
}

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There isn't a general way to do this, but for UIActionSheet specifically, you don't need to use that constructor.

UIActionSheet *sheet = [[UIActionSheet alloc] init];

// set properties
sheet.title = @"Title!";

// add buttons
for (NSString *buttonTitle in otherButtonTitles) {
    [sheet addButtonWithTitle:buttonTitle];
}

sheet.cancelButtonIndex =
    [sheet addButtonWithTitle:@"Cancel"];

UIAlertView can be initialized in a similar way.