SKAction: how to generate a random delay in generation of nodes - ios

Question

I use the following piece of code to generate SKNodes periodically. Is there a way to make the period of generation of these SKNodes random. Specifically, how do I make the "delayFish" in the following code an action with a random delay?
[self removeActionForKey:#"fishSpawn"];
SKAction* spawnFish = [SKAction performSelector:#selector(spawnLittleFishes) onTarget:self];
SKAction* delayFish = [SKAction waitForDuration:3.0/_moving.speed];
SKAction* spawnThenDelayFish = [SKAction sequence:#[spawnFish, delayFish]];
SKAction* spawnThenDelayFishForever = [SKAction repeatActionForever:spawnThenDelayFish];
[self runAction:spawnThenDelayFishForever withKey:#"fishSpawn"];

Answer 1

ObjC:
First set an average delay and range...
#define kAverageDelay 2.0
#define kDelayRange 1.0 // vary by plus or minus 0.5 seconds
and then change your delayFish action to this...
SKAction* delayFish = [SKAction waitForDuration:kAverageDelay withRange:kDelayRange];
Swift:
First set an average delay and range...
let averageDelay:TimeInterval = 2.0
let delayRange:TimeInterval = 1.0 // vary by plus or minus 0.5 seconds
and then change your delayFish action to this...
let delayFish = SKAction.wait(forDuration:averageDelay, withRange:delayRange)

Answer 2

Insert a random float instead of a fixed one.
In your case something like this:
double value = ((double)arc4random() / ARC4RANDOM_MAX)
* (maxValue - minValue)
+ minValue;
SKAction* delayFish = [SKAction waitForDuration:value/_moving.speed];
I see. This won't work in your case as repeatActionForever will run with the last created random value. Forever.
Maybe try this instead. I'm not sure if this works though:
SKAction* delayFish = [SKAction waitForDuration: (((double)arc4random() / ARC4RANDOM_MAX) * (maxValue - minValue)+ minValue)/_moving.speed];
I suggest making the random value an own method though.
-(double) getRandomValue(){
return (((double)arc4random() / ARC4RANDOM_MAX) * (maxValue - minValue)+ minValue);
}
EDIT:
Here is a link to a similar issue. Maybe that might help. Sorry!
SKAction *randomXMovement = [SKAction runBlock:^(void){
NSInteger xMovement = arc4random() % 20;
NSInteger leftOrRight = arc4random() % 2;
if (leftOrRight == 1) {
xMovement *= -1;
}
SKAction *moveX = [SKAction moveByX:xMovement y:0 duration:1.0];
[aSprite runAction:moveX];
}];
SKAction *wait = [SKAction waitForDuration:1.0];
SKAction *sequence = [SKAction sequence:#[randomXMovement, wait]];
SKAction *repeat = [SKAction repeatActionForever:sequence];
[aSprite runAction: repeat];
Source: SKAction: How to Animate Random Repeated Actions