using robotlegs i always retrieve this error. I have not idea whats wrong.
TypeError: Error #1009: Cannot access a property or method of a null
object reference.
at org.robotlegs.mvcs::Actor/dispatch()[/Users/shaun/Documents/
Development/Workspaces/GanymedeFB4/robotlegs-framework/src/org/
robotlegs/mvcs/Actor.as:57]
Model
package com.something.model {
// someimports
public class PhotoModel extends Actor {
public function uploadAndDetect() : void {
// something
dispatch(new DetectEvent(DetectEvent.DETECTED));
}
}
}
Event
package com.something.events {
// someimports
public class DetectEvent extends Event {
public static const DETECTED : String = "DETECTED";
public function DetectEvent(type:String, bubbles:Boolean = false, cancelable:Boolean = false){
super(type, bubbles, cancelable);
}
override public function clone():Event{
return new DetectEvent(type, bubbles, cancelable);
}
}
}
I can't read German well enough to be sure, but I'd suspect that the issue is that your Model isn't getting injected with the Event Bus (IEventDispatcher shared by just about everything Robotlegs needs to communicate with).
How are you instantiating this? Are you running this from a Unit test? If so, you need to set the eventDispatcher on your Model. If not, you need to use mapClass, mapSingleton, or mapSingletonOf to make sure your Model gets instantiated with the things it needs to work as an Actor.
When and where are creating the Model? I bet that your are not injecting its dependencies.
The model should be created in a Command and the use:
var model: PhotoModel = new PhotoModel();
injector.injectInto(model);
And then the eventDispatcher (the only dependency of Actor) should be injected.
Related
I have Flex/Java project with blazeDS. Now I have an actionscript file that call a method of another actionscript that call the remoteObject (java class who make a simple select on db)
Here's the code:
Home.as
..
private var _dm:DataManager = new DataManager;
public function getPerson():void { // this is connect to a button in .mxml
_dm.getPerson();
}
..
DataManager.as
public class DataManager {
private var _service:RemoteObject;
private var _url:URLRequest;
private var loCs:ChannelSet = new ChannelSet();
public function DataManager () {
_service = new RemoteObject("PeopleDAO");
loCs.addChannel(new AMFChannel("canale", "http://localhost:8080/FlexTRYOUT/messagebroker/amf"));
_service.channelSet = loCs;
}
private function onFault(event:FaultEvent,token:Object):void {
var _fail:String = "fault";
}
private function onResult(event:ResultEvent,token:Object):void {
per = event.result as People; // is a bean class
Alert.show(per.nome);
}
public function getPerson():void {
var token:AsyncToken = _service.getPersona();
token.addResponder(new AsyncResponder(onResult,onFault));
}
}
The call works fine, it calls java method names getPerson() of the DataManger.java class. It return simply one object with name and surname (it's just a hello world to understand this damned AsyncCall). The problem is that I don't know how send this result to Home.as with a classic (java) return type. I have the result in onResult method and I don't know how to get it.
I try to follow Brian instructions and I just waste my time. Maybe because I'm not a flex actionscript programmer but I added the code Brian posted and:
public function getPerson():void { // this is connect to a button in .mxml
_dm.addEventListener(DATA_RECEIVED, onPersonFound); * compile error 1
_dm.getPerson();
}
error is DATA_RECEIVED is undefined
than in DataManager:
public class DataManager {
public static const DATA_RECEIVED:String = "DATA_RECEIVED";
...
private function onResult(event:ResultEvent,token:Object):void {
per = event.result as People; // is a bean class
dispatchEvent(new DataReceivedEvent(DATA_RECEIVED, per)); * compile error 2
}
}
error 2 is call of possible undefined method dispatchEvent
Where is the mistake? Please guys write the complete code because I'm on flex - actionscript - blazeds from two days and I have a few time to try solution. Thanks
OK, Sorry for all this post, I just create new one (but more elaborated and clear) with the same question. Step by Step I'm studing this language and I manage to implement the Brian code but DataManager.as class must extend EventDispatcher, if I don't extend this I have the compile error I posted. At moment I mangage to obtain the resultEvent data in the method defined in the addEventListener call (onPeopleFound in this case). Thanks a lot Brian I think I surely need your help again in future (at least until acceptance of the project). Bye
You can adjust method getPerson to have two parameters referencing the callback functions.
public function getPerson(onResultCallback:Function, onFaultCallback:Function):void {
var token:AsyncToken = _service.getPersona();
token.addResponder(new AsyncResponder(onResultCallback,onFaultCallback));
}
This way you can receive data in an instance of the class you need.
One option is to dispatch an event when you get the data back from the Java call:
Home.as
...
public function getPerson():void { // this is connect to a button in .mxml
_dm.addEventListener(DATA_RECEIVED, onPersonFound);
_dm.getPerson();
}
private function onPersonFound(dataEvent:DataReceivedEvent):void {
var person:People = dataEvent.people;
//Do important processing...
}
...
In DataManager.as
public class DataManager {
public static const DATA_RECEIVED:String = "DATA_RECEIVED";
...
private function onResult(event:ResultEvent,token:Object):void {
per = event.result as People; // is a bean class
dispatchEvent(new DataReceivedEvent(DATA_RECEIVED, per));
}
}
And DataReceivedEvent.as will look like the answer to How to dispatch an event with added data - AS3
public class DataReceivedEvent extends Event
{
public static const DATA_RECEIVED:String = "DATA_RECEIVED";
// this is the object you want to pass through your event.
public var result:Object;
public function DataReceivedEvent(type:String, result:Object, bubbles:Boolean=false, cancelable:Boolean=false)
{
super(type, bubbles, cancelable);
this.result = result;
}
// always create a clone() method for events in case you want to redispatch them.
public override function clone():Event
{
return new DataReceivedEvent(type, result, bubbles, cancelable);
}
}
Given the following code:
Class CEvent:
public class CEvent extends Event
{
public static const TYPE:String = "cEvent";
private var m_strCode:String;
public function get code():String
{
return m_strCode;
}
public function CEvent(pCode:String, bubbles:Boolean=false,
cancelable:Boolean=false)
{
super(TYPE, bubbles, cancelable);
m_strCode = pCode;
}
}
Class A:
dispatchEvent(new CEvent(MY_CONST))
Class B:
m_a = new A();
m_a.addEventListener(CEvent.TYPE, onCEvent);
.
.
.
private function onCEvent(pEvent:CEvent):void
{
switch (pEvent.code)
{
case A.MY_CONST:
dispatchEvent(pEvent);
}
}
Class C:
m_b = new B();
m_b.addEventListener(CEvent.TYPE, onCEvent);
.
.
.
private function onCEvent(pEvent:CEvent):void
{ // breaks right here
}
I get this error when it breaks on class C, after dispatching it originally from Class A:
Error #1034: Type Coercion failed: cannot convert flash.events::Event#9861089 to
<path>.CEvent.
This doesn't seem to make a lot of sense, and it seems to be going completely against the way inheritance works. Even if there were code in Adobe's implementation of dispatchEvent() that specifically goes through and shaves off anything that's been added through inheritance and just dispatches a "normal" Event instance, that should cause it to break in class B, not C.
Could someone please explain? Thanks.
Edit: By the way changing class B's code to do this instead makes everything work just fine:
dispatchEvent(new CEvent(pEvent.code));
I still need to understand what the issue is though. Thanks.
The error occurs because you have not implemented the clone() method in your custom event.
When you re-dispatch an event (in your Class C), Flash clones the event instead of just re-dispatching the original event.
The event that is re-dispatched therefore is a plain old Event object, because that's what the default clone() method returns.
In general, you should always implement a clone() method for your custom events. It's pretty straight forward to do. In this case it should look something like this:
override public function clone():Event
{
return new CEvent(m_strCode, bubbles, cancelable);
}
Does anyone know of a framework, preferably some way to have the Flex compiler run an extension or perhaps just a build step that we could generate strongly typed proxy classes of our application's data models.
There are 2 main things we want to do with the proxy's:
At runtime we want to lazily parse and instantiate the instance as accessed (similiar to how Java's Hibernate has Lazy proxy objects)
In an editor application we want to implement setter calls so we can track which objects have been modified
The Proxy is really necessary in this situation beyond things like programatically setting up ChangeWatcther's because we need to track Array adds/remove and possibly track "reference" objects so that when a "reference key" is changed we know to save those objects that are referencing it by key
In the first case we want the proxy to basically abstract when that object is loaded from serialized data, but still pass around references of it with the same public properties and data access pattern if it were the real object.
Basically the proxy would instantiate the object the first time a method is called on it.
I know we could use some AS3 byte-code libraries like as3-commons-bytecode.
Or possibly repurposing the GraniteDS Code Generation.
I'd prefer to generate code because it is a deterministic thing and it'd be nice if we could have a way to debug it at runtime easier.
Does anyone know if I could do something like MXMLC does when it generates AS3 code from MXML files.
Also is there anyway to control "when" in the compilation pipeline I can generate code, because we have a lot of data objects using public fields instead of getter/setters, but that are [Bindable] and so if I could generate the proxy based on the generated getter/setter methods that would work.
Here's an example application data object and proxy classes:
[Bindable]
public class PersonDTO implements Serializable {
private var _name:String;
private var _age:Number
public function get age():Number {
return _age;
}
public function set age(a:Number):void {
_age = a;
}
public function get name():String {
return _name;
}
public function set name(n:String):void {
_name = n;
}
public void readObject(data:*) {
//...
}
}
// GENERATED CLASS BASED ON PersonDTO
public class LazyProxy_PersonDTO extends PersonDTO {
private var _instance:PersonDTO = null;
private var _instanceData:*;
private function getInstance():void {
if (_instance == null) {
_instance = new PersonDTO();
_instance.readObject(_instanceData);
}
}
override public function get age():Number {
//Ensure object is instantiated
return getInstance().age;
}
override public function get name():String {
//Ensure object is instantiated
return getInstance().name;
}
}
// GENERATED CLASS BASED ON PersonDTO
public class LogChangeProxy_PersonDTO extends PersonDTO {
//This will be set in the application
public var instance:PersonDTO;
//set by application
public var dirtyWatcher:DirtyWatcherManager;
override public function set age(a:Number):void {
dirtyWatcher.markAsDirty(instance);
instance.age = a;
}
}
Digging a little deeper into AS3-Commons byte code library it looks like they support generating proxy classes and interceptors.
http://www.as3commons.org/as3-commons-bytecode/proxy.html
public class DirtyUpdateInterceptor implements IInterceptor {
public function DirtyUpdateInterceptor() {
super();
}
public function intercept(invocation:IMethodInvocation):void {
if (invocation.kind === MethodInvocationKind.SETTER) {
if (invocation.arguments[0] != invocation.instance[invocation.targetMember]) {
invocation.instance.isDirty = true;
}
}
}
}
I was wondering what the appropriate form was when creating custom events? Should one create a CustomEvent class, and then create a temporary dispatcher in the function, and dispatch the CustomEvent. or is it better to attempt to create a CustomEventDispatcher class, and create the CustomEvent class as an internal class of that class, eg:
package
{
public class CustomEventDispatcher extends EventDispatcher
{
public function CustomEventDispatcher()
{
super(new CustomEvent());
}
}
}
class CustomEvent
{
public function CustomEvent(type:String, bubbles:Boolean=false, cancelable:Boolean=false)
{
super(type, bubbles, cancelable)
}
}
Unilaterally, it is better to make events publicly accessible. This way you can type your listeners (good for code hinting and debugging) and have the Event have public static const types (which you also may want to look in to).
There are two basic questions to answer, when conceiving event mechanics.
1) How do I create dispatcher instance for my events?
General options are: extend EventDispatcher, or aggregate dispatcher instance.
Most basic and common practice (and official docs also state that), is extending EventDispatcher class, thus giving your classes event-dispatching capabilities.
Pros: simple to implement -- just type extends EventDispatcher, and you are done.
Cons: you can't extend something else. Apparently, this is the reason why many native classes are EventDispatcher's grandchildren. Just to spare us the trouble, I guess.
Second general approach is aggregating a dispatcher instance.
package
{
import flash.events.Event;
import flash.events.EventDispatcher;
import flash.events.IEventDispatcher;
public class ClassA implements IEventDispatcher
{
private var dispatcher:EventDispatcher;
public function ClassA()
{
initialize();
}
private function initialize():void
{
dispatcher = new EventDispatcher(this);
}
public function addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void
{
dispatcher.addEventListener(type, listener, useCapture, priority, useWeakReference);
}
public function removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void
{
dispatcher.removeEventListener(type, listener, useCapture);
}
public function dispatchEvent(event:Event):Boolean
{
return dispatcher.dispatchEvent(event);
}
public function hasEventListener(type:String):Boolean
{
return dispatcher.hasEventListener(type);
}
public function willTrigger(type:String):Boolean
{
return dispatcher.willTrigger(type);
}
}
}
Note: we pass a reference to aggregating class to dispatcher constructor.
This is done to make event.target reference your class instance and not the dispatcher instance itself.
Pros: you are free to extend whatever you like. You may do some tricks with dispatcher hooks like maintaining listeners list or something alike.
Cons: not as simple as the first approach.
2) How do I pass custom data with my events?
General options are: pass data in an event instance, or only use event.target reference in event handler to access some data from source.
If you choose to access all necessary data through event.target -- no additional work nedded, just cast this reference in event handler to appropriate class.
If you want to pass some data along with event, you subclass Event, and this class should be publicly visible to the code that handles events, as the answer above states. AS3 is all about strict and strong typing, so why would you resist that?
Overriding clone() method in an Event subclass is only necessary if you are going to redispatch handled events. The official docs say you must do that every time you create a custom event class, just to be safe.
don't forget to override clone. it's also a good idea to override toString for debugging.
here's an example of one of my custom events:
package com.mattie.events
{
//Imports
import flash.events.Event;
//Class
public class SearchFieldEvent extends Event
{
//Constants
public static const SEARCH_COMPLETE:String = "search complete";
//Variables
public var totalResults:uint;
public var duration:uint;
public var searchText:String;
//Constructor
public function SearchFieldEvent(type:String, totalResults:uint = 0, duration:uint = 0, searchText:String = "")
{
super(type);
this.totalResults = totalResults;
this.duration = duration;
this.searchText = searchText;
}
//Override clone
public override function clone():Event
{
return new SearchFieldEvent(type, totalResults, duration, searchText);
}
//Override toString
public override function toString():String
{
return formatToString("SearchFieldEvent", "type", "totalResults", "duration", "searchText");
}
}
}
What I am trying to do is kind of odd, but I am wondering if anyone can come up with a clever way to do what I want to do. Basically, I want to re-define a named function at runtime. I can do this with anonymous functions, but I can't figure out a way to do it for named functions. I want to do this so that I can implement a "spy" functionality on an object for a testing framework (a port of Jasmine to Flex).
Take, for instance, this class:
public class TestClass
{
public var anonymous:Function = function():void {
trace("original anonymous");
};
public function named():void {
trace("original named");
}
}
I can easily re-define the anonymous function because it is just a variable. Javascript uses this idiom a lot.
var testClass:TestClass = new TestClass();
testClass.anonymous = function():void { trace("overridden anonymous"); }
BUT, when I do the same thing for named functions, you get a compile-time error:
// Does not compile
testClass.named = function():void { trace("overridden named"); }
I tried to make it a bit more "squishy" but this leads to a runtime failure "Cannot assign to a method named on TestClass".
// Compiles with runtime failure
testClass["named"] = function():void { trace("overridden named"); }
Can anyone more clever than I come up with a way to hack this? Can the bytecode be hijacked? Something?
I want to modify an object, not a
class
But object doesn't contain functions, only non-static variables. I tried to use prototype property and replace method there, but original method still gets called instead of injected one.
About "hack" bytecode, do you mean "hack" already loaded SWF in runtime? I think it's not possible. I'm sure, though, you can parse SWF with something like as3swf, find method in bytecode, replace it and save result in new SWF.
I had an idea bout making a function "cache" . This might work with what you need.
Let's say you have a class "Car" with a method you need to redefine at runtime:
public class Car extends Sprite
{
private var functionCache:Function;
public function Car()
{
super();
}
public function flexibleFunction(functionBody:*=null):void{
if(functionBody is Function){
functionBody.call();
functionCache=functionBody;
} else {
functionCache(functionBody);
}
}
}
Usage:
public class Main extends Sprite
{
private var car:Car;
public function Main()
{
car = new Car();
car.flexibleFunction(function(){trace("redefine test #1")});
car.flexibleFunction();
car.flexibleFunction(function(doParametersWork:String="let's see"){trace("redefine test #2: " + doParametersWork);});
car.flexibleFunction("yes they do");
car.flexibleFunction();
}
}
an easy way to accomplish what you want is to simply pass a new function to the original function and execute it from there:
package
{
//Imports
import flash.display.Sprite;
//Class
public class RedefineFunction extends Sprite
{
//Constructor
public function RedefineFunction()
{
originalFunction();
originalFunction(redefinedFunction);
}
//Original Function
public function originalFunction(redefinition:Function = null):void
{
if (redefinition != null)
redefinition();
else
trace("Original Function Definition");
}
//Redefined Function
private function redefinedFunction():void
{
trace("Redefined Function Definition")
}
}
}
traces:
Original Function Definition
Redefined Function Definition