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UpdateAfterEvent with setInterval

updateAfterEvent can be called in conjunction with the setInterval method, let's see what the Adobe documentation tells us about setInterval first.

setInterval function
Calls a function or a method of an object at periodic intervals while a SWF file plays. You can use setInterval() to execute any function repetitively over time.

Let's put it into practise, have a look at the 2 animations below :

As you can see the animation on the right is a lot smoother. You can compare both code and you will see again that the only difference is that we have added updateAfterEvent in the second movie.

// ---------------- code movie 1 ---------------

// The function moveSphere is going to be called every 10ms
setInterval(moveSphere, 10);

// this is our main function that will animate the ball
function moveSphere() {
if (greenSphere._x>220) {
sphereDirection = "left";
}
if (greenSphere._x<5) {
sphereDirection = "right";
}
if (sphereDirection == "right") {
greenSphere._x += 2;
} else {
greenSphere._x -= 2;
}
}

// ---------------- code movie 2 ---------------

// The function moveSphere is going to be called every 10ms
setInterval(moveSphere, 10);

Tips regarding the use of setInterval:

- you can clear an interval set by setInterval by using the method clearInterval. In order to do it you need to assign an ID to a variable, for example :

myInterval = setInterval(myFunction,2000);

function myFunction(){
trace("I will show that message in 2 seconds and just once because after me the interval is cleared");
clearInterval(myInterval);
}

- you can pass parameters to the function you call by using the following syntax :

myInterval = setInterval(myFunction,2000,"Tom",32);

function myFunction(myName,myAge){
trace("my name is "+myName+" and I am"+myAge);
clearInterval(myInterval);
}
// Displays "my name is Tome and I am 32"

I hope this little tutorial will help to understand a bit more why and when to use updateAfterEvent.

Good luck :)

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