How to slowly move item up and down? - actionscript-3

Question

I need to do simple thing, by clicking button 1 time, slowly move item1 by 100 px up and move down by 100 px. I've tried this, but item1 immediately increasing by 50px and immediately decreasing by 50px, I need to make It slower.
var moving:Boolean = false;
if(!moving){
item1.y -= 50;
moving = true;
}
else {
item1.y += 50;
moving = false;
}

Answer 1

You could set up a max moving value like 50, and then move the item1 on the Y with 1, and decrease that max value by 1. When the max value reaches 0, the item reached it's destiny.
if(!moving){
item1.y-=1;
maxValue--;
if(maxValue==0){
//reached final position
}
}

Answer 2

Use a Timer object. Declare that object inside of your class. Then, when the button has been clicked, set the object to a new instance of a Timer that will run very quickly and for many iterations, add an event listener to your new Timer, and in the event listener, apply much smaller increments or decrements to item1.y. For example:
private var m_tmr:Timer;
private function buttonClickHandler(pEvent:MouseEvent):void
{
// This is the function that's called when the button's clicked.
if (m_tmr == null)
{
m_tmr = new Timer(200, 0);
m_tmr.addEventListener(TimerEvent.TIMER, onTimer);
m_tmr.start();
}
}
private function onTimer(pEvent:TimerEvent):void
{
// The first several times this function is called (should be around every
// 200 milliseconds), increment item1.y by 1 or 2 or something else small.
// After the first many times, start decrementing item1.y by the same amount.
// Then call m_tmr.removeEventListener(TimerEvent.TIMER, onTimer);
}

Answer 3

You have to tell Flash to re-draw the screen after each incremental move. An excellent way to do this is with an ENTER_FRAME loop:
var moving:Boolean = false;
const initY = item1.y; // your starting y value
const limitY = initY - 100; // your move will end here
if(!moving){
moving = true;
addEventListener(Event.ENTER_FRAME,moveit)
function moveit(e)
{
item1.y -=1
if (item1.y < limitY)
removeEventListener(Event.ENTER_FRAME,moveit)
}
you have to removeEventListener(...) once you've got to where you want to be, otherwise the loop will go on and hog memory and performance.
UPDATE
So, to move up on a mouse click, you'd do this:
var moving:Boolean = false;
const initY = item1.y; // your starting y value
const limitY = initY - 100; // your move will end here
stage.addEventListener(MouseEvent.CLICK, moveUp)
function moveUp(e)
{
stage.removeEventListener(MouseEvent.CLICK, moveUp)
if(!moving){
moving = true;
addEventListener(Event.ENTER_FRAME,moveit)
function moveit(e)
{
item1.y -=1;
if (item1.y < limitY)
{
removeEventListener(Event.ENTER_FRAME,moveit);
item1.y = limitY;
moving = false;
}
}
}
Instead of targeting stage you may just want to target your button when you use the addEventListener method to register the listener function with the mouse click.
To move back to the start position, apply the same idea to another button or another MouseEvent. For instance you could move up on MOUSE_DOWN and move down on MOUSE_UP.
There are more sophisticated things you can do inside the listener functions (in this case the moving functions). You could apply "easing" to the beginning and ending of the moves so that the motion seems more natural. But, you'll have to read up on that - this answer is too long already!

Answer 4

I would like participate in this conversation. My version of object movement without If statements. Movement is based on trigonometric function:
var objectToAnimate:Shape = new Shape();
objectToAnimate.graphics.beginFill(0x009900);
objectToAnimate.graphics.drawCircle(0, 0, 20);
addChild(objectToAnimate);
//Place it somewhere
objectToAnimate.x = objectToAnimate.y = 200;
//Config for movement
var step:Number = 1; //really slow... 1° per frame
var maxOffsetY:Number = -100; //Move object maximum on 100px top
var cursor:Number = -90;
var position: Number = objectToAnimate.y; // catch current position
var timer:Timer = new Timer(30, 180);
timer.addEventListener(TimerEvent.TIMER, updateAnimation);
timer.start();
function updateAnimation(e:TimerEvent):void {
objectToAnimate.y = position + Math.cos(cursor * Math.PI / 180) * maxOffsetY;
cursor += step;
}