Is there a better way write this objective-c code?

Question

Hi, this code creates a random transition when I change scenes. There are eleven transitions. Because they are static, I think I cannot use NSClassFromString. I also need to pass the scene (s) object. Right now the switch seems redundant. Is there a way to rewrite this to make it more efficient?

-(void) newScene
{
CCScene *s = [CCScene node];
id child = [sceneCharacter node];
[s addChild:child];
int random = arc4random() % 10;


switch (random)
{
    case 1:
        [[CCDirector sharedDirector] replaceScene:[CCFadeTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 2:
        [[CCDirector sharedDirector] replaceScene:[CCFadeTRTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 3:
        [[CCDirector sharedDirector] replaceScene:[CCJumpZoomTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 4:
        [[CCDirector sharedDirector] replaceScene:[CCMoveInLTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 5:
        [[CCDirector sharedDirector] replaceScene:[CCOrientedTransitionScene transitionWithDuration:0.5f scene:s]];
        break;

    case 6:
        [[CCDirector sharedDirector] replaceScene:[CCPageTurnTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 7:
        [[CCDirector sharedDirector] replaceScene:[CCRotoZoomTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 8:
        [[CCDirector sharedDirector] replaceScene:[CCShrinkGrowTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 9:
        [[CCDirector sharedDirector] replaceScene:[CCSlideInLTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 10:
        [[CCDirector sharedDirector] replaceScene:[CCSplitColsTransition transitionWithDuration:0.5f scene:s]];
        break;

    case 0:
        [[CCDirector sharedDirector] replaceScene:[CCTurnOffTilesTransition transitionWithDuration:0.5f scene:s]];
        break;

    default:
        [[CCDirector sharedDirector] replaceScene:s];
}

}

Answer 1

You could put all of your CC*Transition objects into an array, and use the random number to index that array:

transition tt = transitions[random];
[[CCDirector sharedDirector] replaceScheme:[tt transitionWithDuration: 0.5f scene:s]];

Warning as an aside, your random number will only take on the values between 0 and 9. As written, case 10, and the default will never happen.

Answer 2

How about only assigning the variable s and doing the whole call after the switch statement since your only issue is redundancy? Like:

case 1:;
    s = [CCFadeTransition transitionWithDuration:0.5f scene:s]];
    break;

And then call replaceScene after the switch statement:

[[CCDirector sharedDirector] replaceScene:s];

IMHO, that's cleaner.

Answer 3

Least code and extravagant memory usage:

NSArray *sceneClasses = [[NSArray arrayWithObjects:[CCFadeTransition class],
                                                   [CCFadeTRTransition class],
                                                   /*the whole list of 
                                                   transition types*/
                                                   nil] retain];

[[CCDirector sharedDirector] replaceScene:[[sceneClasses objectAtIndex:random] transitionWithDuration: 0.5f scene:s]];