Timeline code:
import as3.first;
first._this=this;
var str1:String='this is timeline';
Class code:
package as3 {
import flash.display.MovieClip;
public class first extends MovieClip {
public static var _this:Object;
trace(_this.str1);
}
}
Error message:
TypeError: Error #1009: Cannot access a property or method of a null
object reference.
Trying to wrap my mind around how classes work. Need to access timeline functions and variables from class. What am I doing wrong and how can I make this work?
All in all what you are doing is somewhat weird. May be, you just want a document class for your SWF root? You as well could add a class to any movieclip in your library: both ways grant you access to timeline.
package as3
{
import flash.display.MovieClip;
public class first extends MovieClip
{
public static var _this:Object;
trace(_this.str1); // you may place code here... but consider this:
// this area is STATIC, the code here
// executes only once when class gets initialized,
// so, this happens BEFORE you assign first._this=this;
}
}
Related
I'm trying to debug a library which uses haxe.macro.TypeTools::findField. I've created a simple code for that:
package;
using haxe.macro.TypeTools;
class Main
{
public function new()
{
var test = findField(Child, "hello");
trace(test);
}
}
class Base
{
private function hello()
{
}
}
class Child extends Base
{
public function new() {}
}
However I'm getting error Unknown identifier : findField. Is this because it can only be used in build macro context?
This is what I'm trying to emulate.
First of all, function findField() is not from the haxe.macro.TypeTools.
It is a helper function from edge.core.macro.Macros.
To use it without a class path, import it's class with a wildcard import edge.core.macro.Macros.*
Secondly, findField() should be used in a build macro context only, since it expects Array<Field>, which is obtained by haxe.macro.Context.getBuildFields().
Lets assume i have a class which has the same name as an previously defined type which is defined inside lib.d.ts. How would i make use of that type within this class.
For example, i have the class Event, which has to deal with the browsers Event object, which is defined as an interface in lib.d.ts.
export class Event { // own definition of Event which hides original Event
public dealWithBrowserEvent(event: Event): void { // Event object defined by lib.d.ts
// deal with it
}
}
How would i tell Typescript that this are two different types. Of course i could simply rename my class, but i don't want to do that, because the name is perfect for my use case.
You can archive this by doing so:
E.ts:
class CustomEvent
{
public dealWithBrowserEvent(event: Event): void
{
}
}
export default CustomEvent;
A.ts:
import Event from './E'
export class SomeClass
{
//Parameter e here is instance of your CustomEvent class
public someMethod(e: Event): void
{
let be: any;
//get browser event here
e.dealWithBrowserEvent(be)
}
}
More on declaration merging, and what can be merged and what not: link
I strongly recommend you not doing so. This code will lead to a lot of confusion for your colleagues reading/modifying it later, let alone headache of not being able to use in the same file standard class for Event.
In the meantime i found a quite doable solution. I defined an additional module which exports renamed interfaces. If i import this module, i can use the renamed types as if they would be original types.
browser.ts
// Event will be the one from lib.d.ts, because the compiler does not know anything about
// the class Event inside this module/file.
// All defined properties will be inherited for code completion.
export interface BrowserEvent extends Event {
additionalProperty1: SomeType;
additionalProperty2: SomeType;
}
If you don't need additional properties you can just do type aliasing:
browser.ts
// Alias for Event
export type BrowserEvent = Event;
event.ts
import {BrowserEvent} from './browser.ts';
export class Event { // Definition of Event hides original Event, but not BrowserEvent
public dealWithBrowserEvent(event: BrowserEvent): void {
// deal with it
}
}
I'm quite happy with this solution, but maybe there is a even better solution.
I have an OnMethodBoundaryAspect and within the CompileTimeValidate method I'd like to verify that the Aspect attribute is being applied at the class level.
example:
[MyCustomAspect]
public class SomeClass
{
...
I wouldn't like this to throw a compilation error.
example:
public class SomeClass
{
[MyCustomAspect]
public void SomeMethod() {
...
How can I detect where my Aspect attribute is being applied?
The moment when CompileTimeValidate method executes is already too late to validate the attribute application. The "attribute multicasting" step runs first, and it will propagate the method level aspect applied on a class to the class methods, removing the original attribute at the same time.
To validate the attribute application you can configure the valid targets with [AttributeUsage].
[Serializable]
[AttributeUsage(AttributeTargets.Class)]
public class MyCustomAspect : MethodLevelAspect
{
// ...
}
Is there a better way to hook up dependencies??
This relies on the singleton App.Current and exposing a function that exposes the _container.SatisfyImports.
Is there a more MEF-tastic way of doing things?
Here is part of my main application class
public partial class App : Application
{
private CompositionContainer _container;
....
public void SatisfyImportsOnce(Object satifyMe)
{
_container.SatisfyImportsOnce(satisfyMe);
}
}
Here is a test class instantiated long after ComposeParts is called...
public class TestClass
{
public TestClass()
{
Console.WriteLine("Created a TestClass");
((Microsoft.Samples.XFileExplorer.App)App.Current).SatisfyImportsOnce(this);
}
}
I am in a similar situation in a WPF application where I want the MainWindow instance to import MEF exports. Since MEF does not create the MainWindow instance, it will not satisfy the imports unless you tell it to.
The way you are doing it will work if you do not want your instance to be registered for recomposition. If you do want recomposition, you should call ComposeParts.
Recomposition will update the imports in your class if and when they change.
I have a class that extends AbstractGinModule
like:
public class ClientModule extends AbstractGinModule {
public ClientModule() { }
#Override
protected void configure() {
...
...
bind(...class).annotatedWith(...).to(...class).in(Singleton.class);
...
}
}
The idea that I have is to bind one class with another class based on a value stored in a property file.
like:
param contains the value coming from the property file
if(param.equals("instanceB"))
bind(a.class).to(b.class)
else
bind(a.class).to(c.class)
I have a class that access this property file and return a string with the value.
This class is called: InstanceParameters.java
I would like to get an instance of this class within my ClientModule.
But I don't find any way to do it.
I tried with:
- InstanceParameters param = new InstanceParameters ();
- GWT.create(InstanceParameters.class); (Error because this method should only be used on the client side)
Is there a way to access this InstanceParameters class within this clientModule?
Thank you for your help
You don't need to read the file before launching the application - just before creating the AbstractGinModule (via GWT.create). So, load the Dictionary in your onModuleLoad method and pass the parameters, either as a whole InstanceParameters class or as the extracted String, via a provider or any other means.