I have a collection of objects and each object throws an event every time its value gets updated. Im trying to capture that event by adding a listener to the arraycollection that holds it (see main class) but its not working. Honestly I'm not sure this is the correct approach.
I'm avoiding using Collection.CHANGE because it fells into an infinite recursion ultimately ends in a stack overflow. Any ideas?
[Bindable]
public class NamesVO {
public var steveList:ArrayCollection; // array of SteveVO objects
public function NamesVO() {
steveList = new ArrayCollection();
}
public function rename():void {
for each(var steve:SteveVO in steveList) {
steve.rename();
}
}
}
[Bindable]
public class SteveVO extends EventDispatcher {
public static const VALUE_CHANGED:String = "VALUE_CHANGED";
public var code:String;
public var name:String;
public var _quantity:Number;
public function SteveVO() {
this.code = "";
this.name = "";
_quantity = 0;
}
public function get quantity():Number {
return _quantity;
}
public function set quantity(quantity:Number):void {
_quantity = quantity;
dispatchEvent(new Event(VALUE_CHANGED));
}
public function rename():void {
name = code + " - " + _quantity;
}
}
Main class:
names = new NamesVO();
names.steveList.addEventListener(SteveVO.VALUE_CHANGED, function():void {
names.rename(); // this anon function is not being executed!!
});
var steve:SteveVO = new SteveVO();
names.steveList.addItem(steve);
// names is bound on a datagrid and uses itemeditor for each SteveVO object
The VALUE_CHANGED event is not dispatched by the steveList array Collection so won't be detected by your listener. You could encapsulate the functionality you want inside the NamesVO class by detecting when an item is added to the array collection and adding a listener to the new steveVO object that dispatches the same event from NamesVO. Then just listen for that event in your main class.
Is there a reason to change all the names when one quantity is changed. Would it be better simply to call rename inside the set function of the steveVO class?
To implement the change:
import flash.events.Event;
import mx.collections.ArrayCollection;
import mx.events.CollectionEvent;
import mx.events.CollectionEventKind;
[Bindable]
public class namesVO
{
public var steveList:ArrayCollection; // array of SteveVO objects
public function namesVO()
{
steveList = new ArrayCollection();
steveList.addEventListener(CollectionEvent.COLLECTION_CHANGE,collChanged);
}
private function collChanged(e:CollectionEvent):void
{
if (e.kind == CollectionEventKind.ADD)
e.items[0].addEventListener(steveVO.VALUE_CHANGED,valueChanged);
}
private function valueChanged(e:Event):void
{
dispatchEvent(new Event(steveVO.VALUE_CHANGED));
}
public function rename():void
{
for each(var steve:steveVO in steveList)
{
steve.rename();
}
}
}
In the main class use:
names = new namesVO();
names.addEventListener(steveVO.VALUE_CHANGED, function():void
{
names.rename();
});
steve = new steveVO();
names.steveList.addItem(steve);
steve.quantity = 12;
Of course this is only an example and only includes the case where one item is added at a time.
Related
i want to call an external function inside a class. thats the code;
in checkConnectionStatus function,
this[_funcNameForSucceededCon].apply(); doesnt work because "this" is the class, not the Application. How can i reach Application at this time or what can i do?
any help will be greatly appreciated.
best regards,
mira.
package myLibrary
{
import air.net.URLMonitor;
import flash.events.Event;
import flash.events.StatusEvent;
import flash.net.URLRequest;
public class connectionControl
{
private var _urlReq:URLRequest;
private var _urlMonitor:URLMonitor;
private var _funcNameForSucceededCon:String;
private var _funcNameForFailedCon:String;
public function connectionControl(targetURL:String, funcNameForSucceededCon:String, funcNameForFailedCon:String)
{
_urlReq = new URLRequest(targetURL);
_urlMonitor = new URLMoniotor(_urlReq);
_urlMonitor.addEventListener(StatusEvent.STATUS, checkConnectionStatus);
_funcNameForSucceededCon = funcNameForSucceededCon;
_funcNameForFailedCon = funcNameForFailedCon;
if(_urlMonitor.running == false)
{
_urlMonitor.start();
}
else
{
_urlMonitor.stop();
_urlMonitor.start();
}
}
private function checkConnectionStatus(e:Event):void
{
_urlMonitor.removeEventListener(StatusEvent.STATUS, checkConnectionStatus);
if(_urlMonitor.available)
{
this[_funcNameForSucceededCon].apply();
}
else
{
this[_funcNameForFailedCon].apply();
}
}
}
}
You have passed the name of the function to be serving as a callback. Use instead the function itself and pass it to connectionControl.
public class connectionControl
{
private var _funcSucceededCon:Function;
private var _funcFailedCon:Function;
public function connectionControl(targetURL:String, funcSucceededCon:Function, funcFailedCon:Function)
{
_urlReq = new URLRequest(targetURL);
_urlMonitor = new URLMoniotor(_urlReq);
_urlMonitor.addEventListener(StatusEvent.STATUS, checkConnectionStatus);
_funcSucceededCon= funcSucceededCon;
_funcFailedCon= funcFailedCon;
...
And:
if(_urlMonitor.available)
{
_funcSucceededCon();
}
I am trying to make a class that staggers the net connections calls by a certain amount to not put too much pressure on my server, and so I don't have a dozen net connectors running around in my code.
I want a class that I can send a call command to, the class adds the call to the queue, and then about every one second it see if anything is in the queue, and if so calls it. This is what I have so far.
package net
{
import flash.events.TimerEvent;
import flash.net.NetConnection;
import flash.net.Responder;
import flash.utils.Timer;
public class Server
{
private static var gateway:String = "http://localhost/gateway.php";
private static var queue:Vector.<ServerNode>
private static var nc:NetConnection;
private static var instance:Server = null;
private static var res:Responder;
private var timer:Timer;
public function Server(e:ServerEnforcer) {
nc = new NetConnection();
queue = new Vector.<ServerNode>();
timer = new Timer(1000);
timer.addEventListener(TimerEvent.TIMER, execCall);
timer.start();
}
public static function getInstance():Server {
if (instance == null) {
instance = new Server(new ServerEnforcer);
}
return instance;
}
private function execCall(e:Event):void {
if (queue.length > 0) {
var node:ServerNode = queue.pop();
nc.call(node.method, node.res, node.args);
}
}
public function call(method:String, success:Function, failure:Function, ...args):void {
queue.unshift(new ServerNode(method, success, failure, args));
}
private function serverFailure(event:Object):void {
trace("Server Failure : " + event.description);
}
}
}
import flash.net.Responder;
class ServerEnforcer { }
class ServerNode {
public var method:String;
public var success:Function;
public var failure:Function;
public var args:Array;
public var res:Responder
public function ServerNode(_method:String, _success:Function, _failure:Function, _args:Array) {
method = _method;
success = _success;
failure = _failure;
res = new Responder(success, failure);
args = _args;
}
}
Now when I call
Server.getInstance().call("Fetch.getData", parseAllData, onError)
public function parseAllData(event:Object):void {
trace("Victory!");
}
public function onError(event:Object):void {
trace("Error :" + event);
}
absolutely nothing happens. Any idea why or a point in the right direction why this isn't working?
You created an instance of the NetConnection, but haven't actually initiated a connection with the server.
In other words,
nc.connect(gateway);
is missing.
See NetConnection documentation for more information on that class.
There are 3 properties (example 1):
[Bindable] public var name:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
I needed to have 3 helper methods that will be bindable too (example 2):
[Bindable] public var name:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
public function get nameIsOk():Boolean { return !Strings.isEmpty(name) }
public function get emailIsOk():Boolean { return email == 3 }
public function get addressIsOk():Boolean { return address }
Sure, the code above doesn't work. I made it work by doing this (example 3):
private var _name:String
[Bindable("nameChanged")]
public function get name():String { return _name }
public function set name(v:String):void { _name = v; dispatchEvent(new Event("nameChanged")) }
[Bindable("nameChanged")]
public function get nameIsOk():Boolean { return !Strings.isEmpty(name) }
private var _email:Number
[Bindable("emailChanged")]
public function get email():Number { return _email }
public function set email(v:Number):void { _email = v; dispatchEvent(new Event("emailChanged")) }
[Bindable("emailChanged")]
public function get emailIsOk():Boolean { return email == 3 }
private var _address:Boolean
[Bindable("addressChanged")]
public function get address():Boolean { return _address }
public function set address(v:Boolean):void { _address = v; dispatchEvent(new Event("addressChanged")) }
[Bindable("addressChanged")]
public function get addressIsOk():Boolean { return address }
It does work, but now it is bloated.
Is there a way to reduce this code (example 3) to something smaller (like example 2)?
UPDATE:
Kudos to just_a_dude for nice answer. Here is the final version:
[Bindable] public var name:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
public function Remixer() {
for each (var f:String in Strings.split("name email address")) {
ChangeWatcher.watch(this, f, onChange)
}
}
private function onChange(e:PropertyChangeEvent):void {
dispatchEvent(new Event(e.property + "Changed"))
}
[Bindable("nameChanged")]
public function get nameIsOk():Boolean { return !Strings.isEmpty(name) }
[Bindable("emailChanged")]
public function get emailIsOk():Boolean { return email == 3 }
[Bindable("addressChanged")]
public function get addressIsOk():Boolean { return address }
Not sure if this is what you're looking for but you can use mx.binding.utils.ChangeWatcher to "watch" for property changes
<?xml version="1.0" encoding="utf-8"?>
<mx:Script>
<![CDATA[
import mx.events.PropertyChangeEvent;
import mx.binding.utils.ChangeWatcher;
[Bindable] public var firstName:String;
[Bindable] public var email:Number;
[Bindable] public var address:Boolean;
private var _watcher:ChangeWatcher;
private function init():void {
ChangeWatcher.watch(this, "firstName", propertyChangeHandler);
ChangeWatcher.watch(this, "email", propertyChangeHandler);
ChangeWatcher.watch(this, "address", propertyChangeHandler);
firstName = "foo";
email = 0;
address = true;
firstName = "bar";
email = 1;
address = false;
}
protected function propertyChangeHandler(event:PropertyChangeEvent):void {
var prop:Object = event.property;
var name:String = prop.toString() + "Changed";
// trace(name); // displays firstNameChanged or emailChanged or addressChanged
dispatchEvent(new Event(name));
}
]]>
</mx:Script>
Let me know if this helps
Cheers
I'm not sure if you need getters, but if not, a nice way to do it, is to just use a single function, and put your bindable strings as arguments.
if you put this in your object:
public function isOk(s:String):Boolean
{
return !Strings.isEmpty(s)
}
You would use it like this:
<mx:CheckBox selected="{yourObject.isOk(yourObject.name)}" />
Generally, if you put a function inside the "{}" with parameters which are bindable, it will be called each time that parameter changes.
I would encapsulate your functionality in a class. Do not repeat yourself :)
I have a simple flex3 project with and mxml file (with some as inside of it) and FMSConnection.as
I have something like this
public class FMSConnection extends NetConnection
{
//this methods is called from the media server
public function Message(message:String):void
{
//how to display (add it to a textarea) this message, when this method is invoked ?
}
}
//in the mxml, after FMSConnection is created:
fmsConn.addEventListener(FMSConnection.MESSAGE_RECEIVED, onMessage);
private function onMessage(e:Event):void
{
fmsConn = FMSConnection(e.target);
textArea.text += fmsConn.lastMessage;
}
//FMSConnection
public class FMSConnection extends NetConnection
{
public static const MESSAGE_RECEIVED:String = "messageReceived";
public var lastMessage:String;
public function Message(message:String):void
{
lastMessage = message;
dispatchEvent(new Event(MESSAGE_RECEIVED));
}
}
Instead of declaring the lastMessage variable, you can dispatch a custom event and store the message in it if you want to.
//MsgEvent.as
public class MsgEvent extends Event
{
public static const MESSAGE_RECEIVED:String = "messageReceived";
public var message:String;
public function MsgEvent(message:String, type:String)
{
super(type);
this.message = message;
}
override public function clone():Event
{
return new MsgEvent(message, type);
}
}
//in the mxml, after FMSConnection is created:
fmsConn.addEventListener(MsgEvent.MESSAGE_RECEIVED, onMessage);
private function onMessage(e:MsgEvent):void
{
textArea.text += e.message;
}
//FMSConnection
public class FMSConnection extends NetConnection
{
public function Message(message:String):void
{
dispatchEvent(new MsgEvent(message, MsgEvent.MESSAGE_RECEIVED));
}
}
Overriding the clone method is not necessary in this case, but it's a good practice to follow while using custom events. If you don't override the clone method, you will get a runtime error while trying to redispatch the custom event from the event handler.
private var _product:Product;
[Bindable]
public function get product():Product
{
return _product;
}
public function set product(p:Product):void
{
_product = p;
tn.selectedIndex = 0;
}
<mx:Label text="{product.name}" fontSize="11" fontWeight="bold"/>
How are they getting the product.name value which is inside product class.
package samples.flexstore
{
[Bindable]
public class Product
{
public var productId:int;
public var name:String;
public var description:String;
public var price:Number;
public var image:String;
public var series:String;
public var triband:Boolean;
public var camera:Boolean;
public var video:Boolean;
public var highlight1:String;
public var highlight2:String;
public var qty:int;
public function Product()
{
}
public function fill(obj:Object):void
{
for (var i:String in obj)
{
this[i] = obj[i];
}
}
[Bindable(event="propertyChange")]
public function get featureString():String
{
var str:String = "";
if (triband)
str += "Tri-band ";
if (camera)
str += "Camera ";
if (video)
str += "Video";
return str;
}
}
}
"{product.name}" , the product refers to the getter method!
That's the trick of Flex/ActionScript 3's getter and setter methods
http://livedocs.adobe.com/flex/201/html/wwhelp/wwhimpl/common/html/wwhelp.htm?context=LiveDocs_Book_Parts&file=ascomponents_147_08.html
"name" is a public var on the Product class. By definition, "name" will be accessible to any other class. That's what "public" means.
_product is a private instance of the Product class. They are supplying the set product method with a Product value, which sets the _product private variable to an instance of the Product class.
The bracket notation in the text="{product.name}" portion of the above code is shorthand notation for binding the contained variable, in this case the name property of the product instance, to the component property (text). When the set product method is supplied a Product instance, Flex fires events internally that update the components that have that property bound.
Defining Data Models - Flex Quickstarts