Sprite Kit Calling a random method - iphone

Question

I am currently making a game in sprite kit and i have 8 methods, I have written all the timing code E.T.C so it calls a method every 1 second, but i want it to call a random one of the eight methods, I have been trying to get this working for weeks, any help would be muchly appreciated, Here is my timing code -
- (void)updateWithTimeSinceLastUpdate:(CFTimeInterval)timeSinceLast {
self.lastSpawnTimeInterval += timeSinceLast;
if (self.lastSpawnTimeInterval > 5) {
self.lastSpawnTimeInterval = 0;
[self shoot1];
}
}
- (void)update:(NSTimeInterval)currentTime {
// Handle time delta.
// If we drop below 60fps, we still want everything to move the same distance.
CFTimeInterval timeSinceLast = currentTime - self.lastUpdateTimeInterval;
self.lastUpdateTimeInterval = currentTime;
if (timeSinceLast > 1) { // more than a second since last update
timeSinceLast = 1.0 / 60.0;
self.lastUpdateTimeInterval = currentTime;
}
[self updateWithTimeSinceLastUpdate:timeSinceLast];
}
As you can see instead of [self shoot1]i want it to randomly call one of the eight methods, Also all the methods are named Shoot1, Shoot2, all the way to Shoot8. Thankyou

Answer 1

I can think of two options...
Option 1
Just pick a random number between 1 and 8, and use a switch statement:
- (void)updateWithTimeSinceLastUpdate:(CFTimeInterval)timeSinceLast {
self.lastSpawnTimeInterval += timeSinceLast;
if (self.lastSpawnTimeInterval > 5) {
self.lastSpawnTimeInterval = 0;
int randomNumber = arc4random_uniform(8);
switch(randomNumber) {
case 0:
[self shoot1];
break;
case 1:
[self shoot2];
break;
// ... cases 2-6
case 7:
[self shoot8];
break;
}
}
}
Option 2
Rewrite your shootN methods so that you only have one method that takes an integer as a parameter:
- (void)shoot:(int)index;
Then, you can just do the following:
[self shoot:arc4random_uniform(8)];

Answer 2

You could also live dangerously...
int random = arc4random() % 8;
NSString *selectorName = [NSString stringWithFormat:#"shoot%i", random];
SEL selector = NSSelectorFromString(selectorName);
if ([self respondsToSelector:selector]) {
[self performSelector:selector];
}
This will, by the way, generate a warning when using ARC.