how I can arrange the object on the stage AS3 - actionscript-3

Question

I have a puzzle and 9 pictures, so when I Start Drag any picture i want it to come above of the all remaining.
How I can do it on Action Script 3.0?
this is for example:
import flash.events.Event;
Puz3_Level7A.addEventListener (MouseEvent.MOUSE_DOWN, StartPuz3);
function StartPuz3 (e:Event):void
{
Puz3_Level7A.startDrag();
}
Puz2_Level7A.addEventListener (MouseEvent.MOUSE_DOWN, StartPuz2);
function StartPuz2 (e:Event):void
{
Puz2_Level7A.startDrag();
}
Puz1_Level7A.addEventListener (MouseEvent.MOUSE_DOWN, StartPuz1);
function StartPuz1 (e:Event):void
{
Puz1_Level7A.startDrag();
}

Answer 1

Try following.
import flash.events.Event;
Puz3_Level7A.addEventListener (MouseEvent.MOUSE_DOWN, StartPuz3);
function StartPuz3 (e:Event):void
{
this.setChildIndex(Puz3_Level7A, this.numChildren - 1);
Puz3_Level7A.startDrag();
}
Puz2_Level7A.addEventListener (MouseEvent.MOUSE_DOWN, StartPuz2);
function StartPuz2 (e:Event):void
{
this.setChildIndex(Puz2_Level7A, this.numChildren - 1);
Puz2_Level7A.startDrag();
}
Puz1_Level7A.addEventListener (MouseEvent.MOUSE_DOWN, StartPuz1);
function StartPuz1 (e:Event):void
{
this.setChildIndex(Puz1_Level7A, this.numChildren - 1);
Puz1_Level7A.startDrag();
}
This code assume all the above sprites are children of same sprite.

Answer 2

you can just do
this.parent.addChild(this);
to put 'this' on the top of all parent's children

Answer 3

There are some perfectly good answers already, but in the interest of DRY (don't repeat yourself) and completeness, here is my take on this.
A clean way of doing this, including stopping the drag. No inline functions or unnecessarily repeated code.
//add the mouse down listener to all objects you want to be able to drag.
//if you have a lot, you could also do this in a loop to make it more concise.
Puz3_Level7A.addEventListener(MouseEvent.MOUSE_DOWN, dragPuzzlePiece, false, 0, true);
Puz2_Level7A.addEventListener(MouseEvent.MOUSE_DOWN, dragPuzzlePiece, false, 0, true);
Puz1_Level7A.addEventListener(MouseEvent.MOUSE_DOWN, dragPuzzlePiece, false, 0, true);
var currentPiece:Sprite; //a var to hold a reference to item last mouse downed (to use in the mouse up handler)
//the mouse down handler to drag a piece
function dragPuzzlePiece(e:Event):void
{
currentPiece = e.currentTarget as Sprite; //the event's current target is a reference to the item you added the listener to. We are casting it as a Sprite so the compiler knows what kind of object it is.
addChild(currentPiece); //this will bring it to the top.
//setChildIndex(currentPiece, numChildren-1); //this would do the same as above
//swapChildren(currentPiece, getChildAt(numChildren-1); //this would do the same as above
currentPiece.startDrag(); //start dragging the piece that was clicked
//now listen for the mouse up event to stop dragging the piece
//we listen on the stage, as sometimes dragging can lag when moving the mouse quickly and the mouse may not be over the item when you release the button
stage.addEventListener(MouseEvent.MOUSE_UP, mouseUpHandler);
}
function mouseUpHandler(e:Event):void {
//remove the mouse up listener
stage.removeEventListener(MouseEvent.MOUSE_UP, mouseUpHandler);
//stop the drag:
if(currentPiece) currentPiece.stopDrag();
//do something with currentPiece now that the drag is done.
//like make sure the piece is in a valid spot
//check if the puzzle is complete now
puzzleDone(); //let's say you call this function at some point
}
function puzzleDone():void {
currentPiece = null; //clear this var so objects can be garbage collected
//!important
//when you use setChildIndex, or AddChild, or SwapChildren
//or anything that modifies the parentage of a object
//that object will no longer be removed by timeline keyframes
//it will stick around until it's parent is removed, or you explicitly remove it.
//to that end, you'll want to manually remove your puzzle pieces when done
removeChild(Puz3_Level7A);
removeChild(Puz2_Level7A);
removeChild(Puz1_Level7A);
//you can use some of patterns below for this as well.
}
In regards to adding the mouse down listeners to all your puzzle pieces, here are some other options to scale better if you have a whole lot of pieces:
If the pieces are all FlashPro instance names, you could do this:
//loop three times
for(var i:int=1;i<=3;i++){
//get the child dynamically from the name (
var piece:DisplayObject = getChildByName("Puz" + i + "_Level7A");
if(piece){
piece.addEventListener(MouseEvent.MOUSE_DOWN, dragPuzzlePiece, false, 0, true);
}
}
If your puzzle pieces are the sole children of a common parent (let's say this code is on the timeline of that parent), you could do this:
//loop backwards through all children of this
var i:int = this.numChildren;
while(i--){
this.getChildAt(i).addEventListener(MouseEvent.MOUSE_DOWN, dragPuzzlePiece, false, 0, true);
}
If you have your pieces in an array:
var allPieces:Array = [Puz3_Level7A, Puz2_Level7A, Puz3_Level7A];
for(var i:int=0;i<allPieces.length;i++){
allPieces[i].addEventListener(MouseEvent.MOUSE_DOWN, dragPuzzlePiece, false, 0, true);
}

Answer 4

I upvoted #SameerJain's answer, it will do what you want. Taking it a little further, you can reduce all your repeated code with a simple function that makes your puzzle pieces draggable:
function makeDraggable(target:Sprite):void {
target.addEventListener(MouseEvent.MOUSE_DOWN, dragStart);
}
function dragStart(e:MouseEvent):void {
var target:Sprite = e.currentTarget as Sprite;
target.startDrag();
setChildIndex(target, numChildren - 1);
stage.addEventListener(MouseEvent.MOUSE_UP, dragEnd);
}
function dragEnd(e:MouseEvent):void {
stopDrag();
stage.removeEventListener(MouseEvent.MOUSE_UP, dragEnd);
}
makeDraggable(Puz3_Level7A);
makeDraggable(Puz2_Level7A);
makeDraggable(Puz1_Level7A);