How can I access to an object who fires an eventListener event?
Let's say I have a mc:
var element = new MovieClip();
which has an eventlistener:
element.addEventListener(MouseEvent.CLICK, elementEventHandler);
And then, in the event handler, I want to add something to my mc:
function elementEventHandler(event:MouseEvent):void
{
var b1:balloon = new balloon("ballon1"); //this is another class.
event.target.addChild(b1);//this doesn't work.
}
So that is what I want to achieve... Recover the object who fired the event and then do crazy things with it (in this example, add another object in it).
If anybody has any idea, thanks in advance!
pd: yes, I know I can directly use the var element in this snippet, but in the real code I'm generating the mcs in a loop, according to a xml file.
function elementEventHandler(event:MouseEvent):void
{
// use the as-operator to cast the target into the class you need
var element:DisplayObjectContainer = e.target as DisplayObjectContainer;
// if the cast fails, element will be null, then we bail
if(!element) return;
// then, create your child and add it
var b1:balloon = new balloon("ballon1");
element.addChild(b1);
}
The reason you're getting an error is probably that the event is not coming directly from element but instead from one of its descendant objects.
"click" is a bubbling event.
Check out event flow in the DOM Level 3 Events spec to understand how the capture, target, and bubbling phases work:
http://www.w3.org/TR/DOM-Level-3-Events/#dom-event-architecture
So here's what I would do:
function elementEventHandler(event:MouseEvent):void
{
if (event.target != event.currentTarget)
// If event is not from "element", ignore it.
return;
...
}
Related
I searched quite a bit to find out the correct way to remove event listeners in Cesium. I believe the confusion I have is around whether to treat Cesium events as regular dom events (due to a lack of knowledge about events in general in javascript). I am creating a screen space event like below:
var handler = new Cesium.ScreenSpaceEventHandler(canvas);
handler.setInputAction(function (movement) {
var picked = scene.pick(movement.endPosition);
if (Cesium.defined(picked) && picked.id === someEntity) {
labelEntity.position = someEntity.position;
labelEntity.label.show = true;
} else {
labelEntity.label.show = false;
}
}, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
My question is, how can I remove this event? Is handler.destroy() removes all the event listeners associated with handler, or do I specifically have to remove event listeners by pointing to the cesium map dom element and calling removeEventListener on it? If that's the case, what parameters should be passed to removeEventListener?
The parameters for removeInputAction are just the type and optionally the modifer, and it looks like you're not using the modifier (SHIFT key, ALT key etc.)
So for the code you posted above, the removal would be:
handler.removeInputAction(Cesium.ScreenSpaceEventType.MOUSE_MOVE);
I have created symbols which contain animations (mc1 - mc25). I would like to play these animations if I click on the symbols (click on mc1 -> play mc1, click on mc2 -> play mc2 etc.).
I created an array to address all my symbols in one go. It works ok.
var A:Array = [mc1, mc2, mc3, mc4,...mc25] // create array
car aClip:MovieClip;
for each (aClip in A) // stop all symbols
{aClip.stop();}
How can I get to the result below for all my symbols using an array function?
mc1.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler_4);
function fl_MouseClickHandler_4(event:MouseEvent):void
{
mc1.play();
}
I tried something like this but I couldn't get it work:
aClip.addEventListener(MouseEvent.CLICK, fl_MouseClickHandler);
function fl_MouseClickHandler(event:MouseEvent):void {
aClip.play();
}
Thank you!
The simple way about it is to algorithmically figure which one was clicked. The script below is short and does not contain various checks, it assumes all the elements of A are really MovieClips.
// Assume, you filled the Array with these clips already.
var A:Array;
// Iterate all the clips.
for each (var aClip:MovieClip in A)
{
// Subscribe to each of the clips for the CLICK event.
aClip.addEventListener(MouseEvent.CLICK, clickPlay);
}
// Click event handler function. The point is, you can subscribe it
// to the multiple objects and use the function argument to figure out
// which one of them all is actually the source of the event.
// Furthermore, you can subscribe it to handle multiple events too,
// the argument also carries the id of the event. Sometimes it is
// really simpler to compose a single event-processing gate
// rather then process each one event in a separate handler.
function clickPlay(e:MouseEvent):void
{
// Use e.currentTarget because the initial e.target
// could be not the MovieClip itself, but some interactive
// element deep inside the MovieClip's hierarchy.
// Read about bubbling events (MouseEvent is bubbling)
// to get the whole picture of it.
// Typecasting, because e.target and e.currentTarget
// are of base Object type.
var aClip:MovieClip = e.currentTarget as MovieClip;
// Well, the only thing that is left.
aClip.play();
}
I have an array with movieclips (r1, r2 etc) which are placed on stage dynamically every time there is a hittestobject. I want to add event listener to those movieclips in the array so that every time there is a click on them the last item to be removed. I have this code but it seems to be wrong because only the first element of the array is remove. Can you please help me?
var counter:int = 0;
function releaseToDrop(e:MouseEvent):void
{
Star(e.target).stopDrag();
if (Star(e.target).hitTestObject(target))
{
removeChild(Star(e.target));
var replace:Array = [r1,r2,r3,r4,r5,r6,r7,r8]
addChild(replace[counter]);
counter = counter+1;
}
else
{
trace("No collision.");
removeChild(Star(e.target));
}
}
replace[counter].addEventListener("click", bindClick(o));
function bindClick(o)
{
replace.splice(replace.indexOf(replace[counter]),1);
trace(counter);
}
For one, your bindClick function is inside the releaseToDrop function. This way that function will not be called. Also, try to use the static refence for the click event, so MouseEvent.Click instead of "click".
For your convenience, trace the current state of "counter" in the bindClick function, so you know what element will be removed. You will probably then find out where the flaw is in your logic.
A wise thing to to is also to check counter is not outside the scope of your array. So in bindClick, check for counter < replace.length. (for that the replace array of course has to be defined outside of the function scope of releaseToDrop.
Hope this gets you working in the right direction.
For future references adding addEventListener to the elements of an array so that every time there is a click on them the last item to be removed can be done by this code:
import flash.display.Sprite;
var replace:Array = [r1,r2,r3,r4,r5,r6,r7,r8]
var counter:int = 0;
// Every time there is a hittestobject an element of the array is placed on stage
function releaseToDrop(e:MouseEvent):void
{
Star(e.target).stopDrag();
if (Star(e.target).hitTestObject(target))
{
removeChild(Star(e.target));
addChild(replace[counter]);
counter = counter+1;
trace(counter);
}
}
// The first element of the array has an eventListener and when is clicked the last item of that array shown on stage is removed
var yourSprite:Sprite=new Sprite();
replace.push(yourSprite);
replace[0].addEventListener(MouseEvent.CLICK, myClickHandler, false, 0, true);
function myClickHandler (e:MouseEvent):void
{
counter =counter-1;
if (contains(replace[counter]))
removeChild(replace[counter]);
trace(counter);
}
Can you add an event listener to every movie clip that you spawn, then in each event handler, add a conditional to check if the clicked movie clip is the last item, then remove it (or do whatever you need to to it).
You should also accept Chicken's advice.
I want to set an object to null when it's being clicked and I'm trying to implement this code:
public function onClick(evt:MouseEvent):void{
var thisPatient = evt.target;
thisPatient = null;
}
However, the element is still on the stage.
public function onClick(evt:MouseEvent):void{
var thisPatient = evt.target;
(thisPatient as DisplayObject).parent.removeChild(thisPatient);
//or if thisPatient is this
parent.removeChild(this);
}
But it's bad practive to allow children to remove itself. More right solution is dispathing event because parent must decide remove or not remove child.
public function onClick(evt:MouseEvent):void{
dispatchEvent(new Event("removeMe", true));
}
//parent's code...
child.addEventListener("removeMe", removeHandler);
Setting it to null doesn't suffice. You also have to remove it from its parent container using removeElement() or removeChild() depending on what kind of container you're using.
You just have to do removeChild(thisPatient) and if you put the object inside another object you have to do parent.removeChild(thisPatient)!
In my experience, Register for a events object, you must remove all of the events. all events will be removed completely manually. removeChild on the object that will not release all of the events. the removeChild but, finely memory leak occurs. This is because you did not remove the event. Before you remove an object, you must remove the event.
I have a Movie Clip, and I need to stop the movie when it's reaches a certain frame. To do this, I need to add an event listener that will dispatch when that specific movie clip enters a new frame (as opposed to the whole animation ENTER_FRAME).
bar.addEventListener(Event.ENTER_FRAME, function(e:Event) {
var b:MovieClip = MovieClip(e.currentTarget);
if(b.currentFrame == mp.getPopularity())
b.stop();
});
Any ideas?
Thanks.
Try this;
A simple function:
function playUntil(target:MovieClip, frame:int):void
{
target.stopFrame = frame; // Works because MovieClip is dynamic.
target.addEventListener(Event.ENTER_FRAME, _checkFrame);
}
With the listening function:
function _checkFrame(e:Event):void
{
var m:MovieClip = e.target as MovieClip;
if(m.currentFrame == m.stopFrame)
{
m.stop();
m.removeEventListener(Event.ENTER_FRAME, _checkFrame);
}
}
Apply it to all your instances:
playUntil(instance1, 15);
playUntil(instance2, 27);
playUntil(instance3, 113);
You should remove the event listener when it's no longer needed, otherwise you risk memory leaks. An anonymous function can make this difficult, though you might be able to do it with arguments.callee.
bar.addEventListener(Event.ENTER_FRAME, function(e:Event) {
var b:MovieClip = MovieClip(e.currentTarget);
if(b.currentFrame == mp.getPopularity()){
b.stop();
b.removeEventListener(e.type, arguments.callee);
// ^^ this may work to remove your anonymous listener.
}
});
There's another way to go about this, though. Does mp.getPopularity() change frequently? If it does not change after bar is told to play() then you could use addFrameScript. Just remember that addFrameScript is 0-indexed, so adding a script to frame 1 means you have to pass 0... so if an action is to happen on mp.getPopularity() then you'll have to pass mp.getPopularity() - 1.
var framescript:Function = function():void{
bar.stop();
bar.addFrameScript(bar.currentFrame-1, null);
// ^^ nulling the framescript after
// ^^ it is no longer needed.
}
bar.stop(); // Generally a good idea to call stop before calling addFrameScript
bar.addFrameScript(mp.getPopularity() - 1, framescript);
bar.gotoAndPlay(1); // or wherever it needs to start from.
This is a more precise solution, but you do have to remember to clean up your framescript after you're done, if you plan to use this same bar instance later with a different mp.getPopularity() value.