I was wondering: If I have built a Flex application, is it possible to somehow collect it's class hierarchy using reflection or some other method? For example if I have defined components: CustomButton which derives from Button and RedCustomButton which derives from CustomButton. Is it possible to get a result like: "Button <- CustomButton <- RedCustomButton"?
Thanks in advance for any help!
You can use describeType
trace(describeType(UIComponent));
public function describeType(value:*):XML Reference from Adobe Help
Produces an XML object that describes the ActionScript object named as
the parameter of the method. This method implements the programming
concept of reflection for the ActionScript language.
Also I recommend you to use Spicelib Reflect library.
Related
Working on a Java FXML application called EVIF VideoRouter. Main class is then VideoRouter.java and the controller class is called VideoRouterFXMLController.java.
I have a method in the VideoRouterFXMLController.java class that I need to be able to call from other external classes within the application. Based on extensive searching and reading, I altered the FXML loader code in the main VideoRouter.java class to be thus:
FXMLLoader EVIFloader = new FXMLLoader(this.getClass().getResource("VideoRouterFXML.fxml"));
Parent EVIFroot = (Parent) EVIFloader.load();
VideoRouterFXMLController EVIFcontroller = EVIFloader.getController();
Now, as I understand this process, I'm somehow supposed to create a getter in the main VideoRouter.java class that returns the EVIFcontroller instance I've created above? And then I can use that getter in other classes and call the method inside the returned instance?
If so, I'm having difficulty figuring out where exactly to place the getter. Does it go in the controller class, or the main class? In either case it doesn't seem to be able to see the controller instance in order to return it.
Again, I've searched extensively and the related posts I've found to not appear to address this specific problem I'm having. Any help?
Many thanks in advance!
You have already partly answered your problem: create VideoRouterFXMLController member variable in your VideoRouter class and a getter to expose it, then set it to the controller instance after you load the FXML like in the code snippet your provided.
Having said that, I would propose a different approach to your problem because this approach is generally not a good design due to high coupling between your classes. I would recommend Observer pattern as an alternative approach and EventBus as a library to do this.
I made a custom itemRenderer, and need to access a variable in my Project file (mxml). How can I make my public var available in the custom itemRenderer file?
public function lang_f(trans_short:String):String{
if(outerDocument.language == "de"){
...
}
}
Greetings
Markus
You shouldn't access outer document data from within item renderer. It breaks OOP principles such as low coupling etc. You should either set this data to item renderer with data from data provider or extend your list based component to instantiate renderers with that data. And don't think about MXML component as files. The file structure is just a form of representation. You'd better think MXML files as classes or components — in terms of application structure.
To go along with Constantiner's answer, if you still need to access that variable, you can access the variable in your itemRenderer using outerDocument:
outerDocument.myVariableName
Is the variable defined in main file of your application ? If that's the case you can access is using FlexGlobals.topLevelApplication.YOUR_VARIABLE_NAME
However I agree with Constantiner. This violation of OOP principles. But I hope that solves your problem.
I've got a class called ArtificialIntelligenceBase from which you can create your own artificial intelligence configuration sending some variables to the constructor or you can make a class that inherits from ArtificialIntelligenceBase and in the constructor of this new class just call the function super() with the parameters of the configurations.
I've also created some examples of artificial intelligences in classes, AIPassive, AIAgressive and AIDefensive. Obviously all of them inherits from ArtificialIntelligenceBase.
The point is that there're only few public functions in the base class. The variables in the base class are read only and the non public functions are protected in case you need to apply some modifications on them when created another pre-defined AI.
You can also create another AI just calling the base class sending some parameters in the constructor like this: new ArtificialIntelligenceBase(param1, param2, param3, param4);
I've tought about make the classes as a singleton because the classes can never change and once setted, their variables never change.
The question is: Is the singleton the best pattern to do this? Because I'm not sure.
PD: You don't need to explain any patter, just mention the name and I'll search for how it works
PPD: I'm developing in AS3. Just in case it helps
Thanks
In general, singletons are evil. I don't see any reason in your case to use a singleton, either. It sounds like you're using your own version of a factory method pattern (using a constructor somehow?) or maybe a prototype (I don't know AS3 one bit), but if you're looking for other patterns a couple of other ones are abstract factory and builder.
You don't need to use the singleton pattern to limit yourself to using only one instance per type of class, though. It doesn't help avoid redundancy.
Is there any way to get interface to play along with custom namespace? Example follows.
IHeaderRenderer.as:
public interface IHeaderRenderer{
function set header(value:IHeader):void;
function get header():IHeader;
}
HeaderRenderer.as
import fi.test.internalNamespace;
public class HeaderRenderer implements IHeaderRenderer{
internalNamespace function set header(value:IHeader):void{
// do something
}
internalNamespace function get header():IHeader{
// do something
}
}
This gives you the basic compiler error:
1044: Interface method get header in namespace fi.gridutils.headerrenderers:IHeaderRenderer not implemented by class fi.gridutils.headerrenderers.implementation:HeaderRenderer.
Why is this needed, you might ask. I'm developing a component, where the header accessors should not be directly visible to the components end user (developer), but if the developer wants to create his own Renderer he should know that they are needed. This is because the parent component will use these accessors to give the custom renderer the data it needs to render the header correctly.
Now to my mind there seems to be only three choices:
1) use public access control. This has the setback that the end developer will see accessors, which should not be directly accessed by him. Plus they add unnecessary clutter as they appear in auto-complete.
2) do not use interface. This means the end user has pretty poor options of developing the component further.
3) use the interface, but omit the accessors that use internalNamespace. Now the end developer will not know that he should add also header accessors to his custom headerrenderer class, which ends up in Flash Player giving following error to the developer in runtime:
Cannot create property internalNamespace/::header on fi.gridutils.headerrenderers.implementation.HeaderRenderer.
Sorry for all the blabbing. Any cunning ideas how this kind of situation could be handled?
In ActionScript, the interface methods need to be public. What good is an interface, if you can't guarantee the component using it can access the relevant interface methods?
that said, you can use the exclude metadata to prevent properties from showing up in code hinting.
Something like this:
[Exclude(name="header", kind="property")]
More info
i have in my flex application various mxml components that all need to show stats based on the same data. how can i go about doing that? do i need some mvc framework like cairngrom or puremvc for that or can i do it without them?
any design ideas?
You don't need any framework for that. Do you know about data-binding?
http://www.flexafterdark.com/docs/Flex-Binding
This way you can set your data as dataprovider for many components. For example to show your data in dataGrid you set in mxml it's attribute
dataProvider="{yourDataArrayCollectionIdentifier}"
and in your arrayCollection declaration you need to set metatag [Bindable]
[Bindable] var yourDataArrayCollectionIdentifier : ArrayCollection;
there are other datatypes you can use as dataprovider, just arrayCollection is the most common
There are a handful of approaches to this. For encapsulation purposes, you should isolate your shared data out into a separate class; possibly a Value Object although it does't have to be.
Then create a public variable property in each MXML Component of this classes type. When you create the instance of each mxml component, pass in your 'global' instance of the data class.
You don't need to use an MVC framework, but the Cairngorm Model Locator could also be used to address this problem. The Model Locator is a singleton. You'd store your data inside the singleton instance; and then each MXML Component would reference the singleton for the data. Creating an external dependency like this breaks encapsulation, though. I much prefer the parameter passing route for non-application specific components.
package
{
public class ApplicationViewModel
{
[Bindable] public var message:String = "";
}
}
You can now use this message across your MXML where you make the instance of that.
A singleton class is used in different scenarios where you want to hold some information of all states. A better example would be Chess Board, where your board is Singleton class and its state should never change as you have to keep track of all coins moved across the board and its position.
You are injecting this message variable in the views where you want to show the data.