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Event between actors

I'm trying to use events to do something on actor but i don't understand how to do it properly.
I have a button on my screen and a text (just for example). they are both actors in a stage
my purpose is: if i click on the button, i would like to change text
I add listener on my button, i get the click but i don't know how to send event (or anything else) to my text to set it.
Main class with stage definition and his
public class AGame implements ApplicationListener {
private WorldRendererTouchPad renderer;
private Stage stage;
private static Vector3 cameraVelocity=new Vector3(0,0,0);
private ButtonJump button;
public static final int SCREEN_WIDTH=800;
public static final int SCREEN_HEIGHT=480;
public void create() {
stage = new Stage();
stage.setViewport(SCREEN_WIDTH, SCREEN_HEIGHT, true);
stage.getCamera().translate(-stage.getGutterWidth(), -stage.getGutterHeight(), 0);
renderer = new MyRenderer(SCREEN_WIDTH, SCREEN_HEIGHT);
stage.addActor(renderer);
renderer.create();
button=new ButtonJump();
stage.addActor(button);
button.create();
Gdx.input.setInputProcessor(stage);
}
....
resize and other methods
}
MyRenderer class (contains text actor):
public class MyRenderer {
private TextTest text;
public MyRenderer(float screenWidth, float screenHeight) {
setBounds(0, 0, screenWidth, screenHeight);
}
public void create() {
this.initActors();
}
private void initActors() {
text=new TextTest("Hello world!");
addActor(text);
}
// is it usefull?
public void setText(String newText) {
text.setText(newText);
}
}
and the ButtonJump class (extends MyButton just here for define Skin and ButtonStyle)
public class ButtonJump extends MyButton {
public boolean isJump=false;
private static InputListener buttonListener=new InputListener() {
public boolean touchDown (InputEvent event, float x, float y, int pointer, int button) {
Gdx.app.log("event" , "="+event.toString());
// do something to update text
return true;
}
};
public ButtonJump() {
super();
}
public void create() {
this.setPosition(getStage().getWidth()-60, 30);
this.addCaptureListener(buttonListener);
}
public void capture() {
if (this.isJump)
Gdx.app.log("jump button", "Jump is set");
else
Gdx.app.log("jump button", "No jump");
}
}

If you use the clicklistener you need to let the other actor hold an reference to it to call a method on click. It is not that good to let all Actor know of each other. Use an anonymous way.
There is a "common" system for it in games.
If you really want to use Events, do implement an Event-System. Therefore you have an interface Listen and an Interface Event_Handler. At the start of your game you init one Implementation of the Eventhandler. The interface should at least look like this:
public interface Interface_EventHandler extends Disposable
{
public void handleEvent(final Event... e);
public void registerListener(final Interface_Listen listener,
final Event_Type... type);
public void unregisterListener(final Interface_Listen... listener);
public void unregisterAllListener();
public void unregisterAllListener(final Event_Type... type);
public void processEvents();
public void processEvents(final int maxTimeInMS);
}
Okay so now how does it work. The handler has an hashmap with all eventtypes as Key and an list of listeners as Value. So if someone want to notice an event he registers with the registerListerner at the handler for the right Event_Type (Enum). It need to have the interface Listen to get events. Everyone can now push an Event into the handler with the handleEvent(...) method. Or even more than one.. (varargs) ..
Okay that still does not explain how it work. We now have a registered listener (actor for example) and we have events that get into the handler.
Every Rendercycle you call the processEvents() at the hanlder once. That mean that every event that get pushed in at a frame get handled at the next frame. (Asynchronus) While that he iterates over all events and push them to the listeners. Moreover the listener should have a queue too where they put all events and when they are at their .act() they handle the events. (more asynchronus).
Okay here is an Handler i use:
package com.portaaenigma.eventsystem;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import com.badlogic.gdx.utils.TimeUtils;
import com.portaaenigma.managers.Logger;
public class EventHandler implements Interface_EventHandler
{
private HashMap> listeners;
private LinkedList events;
public EventHandler()
{
listeners = new HashMap<Event_Type, ArrayList<Interface_Listen>>();
// add the arraylist for every Eventtype
for (Event_Type e : Event_Type.values())
{
listeners.put(e, new ArrayList<Interface_Listen>());
}
events = new LinkedList<Event>();
}
#Override
public void handleEvent(final Event... e)
{
for (Event event : e)
{
events.push(event);
}
}
#Override
public void unregisterListener(final Interface_Listen... listener)
{
for (Event_Type e : Event_Type.values())
{
for (Interface_Listen interface_Listen : listener)
{
listeners.get(e).remove(interface_Listen);
}
}
}
#Override
public void processEvents()
{
while (events.size() != 0)
{
// get the first element and delete it
Event e = events.pop();
for (Interface_Listen l : listeners.get(e.getType()))
{
l.handleEvent(e);
}
}
}
#Override
public void processEvents(final int maxTimeInMS)
{
int startSize = 0;
if (events.size() != 0)
{
startSize = events.size();
Logger.log("Processing Events: " + events.size());
}
long startTime = TimeUtils.millis();
while (events.size() != 0)
{
// get the first element and delete it
Event e = events.pop();
for (Interface_Listen l : listeners.get(e.getType()))
{
l.handleEvent(e);
}
// stop handling if time is up
if (startTime - TimeUtils.millis() > maxTimeInMS)
{
Logger.log("Handled " + (events.size() - startSize) + " Events");
break;
}
}
}
#Override
public void registerListener(final Interface_Listen listener,
Event_Type... type)
{
for (Event_Type event_Type : type)
{
listeners.get(event_Type).add(listener);
}
}
#Override
public void unregisterAllListener()
{
Logger.log("UnregisterAll");
for (Event_Type e : Event_Type.values())
{
listeners.get(e).clear();
}
}
#Override
public void unregisterAllListener(final Event_Type... type)
{
for (Event_Type event_Type : type)
{
listeners.get(event_Type).clear();
}
}
#Override
public void dispose()
{
unregisterAllListener();
events.clear();
listeners.clear();
}
}
The interface for all listeners is simple it's just this:
public interface Interface_Listen
{
public void handleEvent(final Event e);
}
Last but not least the event. How can you now send different data? Quiet simple. Have an hashmap out of Strings and Strings and for sure the EventType.
public class Event
{
private Event_Type type;
private HashMap<String, String> m_messages;
public Event(final Event_Type e, final Event_Message... m)
{
m_messages = new HashMap<String, String>();
for (Event_Message message : m)
{
m_messages.put(message.m_key, message.m_value);
}
type = e;
}
public Event_Type getType()
{
return type;
}
public void addMessages(final Event_Message... m)
{
for (Event_Message event_Message : m)
{
m_messages.put(event_Message.m_key, event_Message.m_value);
}
}
public String getMessage(final String name)
{
if (m_messages.get(name) == null)
{
Logger.error("Message not found: " + name);
}
// if null return an empty string
return m_messages.get(name) != null ? m_messages.get(name) : "";
}
public void clearMessages()
{
m_messages.clear();
}
}
Okay i hope this does explain how to implement an EventSystem at a Game. This meight not be the regular way at other Software but in games you queue up the events and handle them once in a Gameloop cycle. Also the listeners do the same.
So in your case. Implement such an handler and register the actors as listener. Sure they need to implement the listener interface and do something with the event. Let the one actor push an event into the handler which directs to the other actor and your are done. And they event dont need to know of each other and it does work for as much actors as you whish. You can even create 1 event for different classes different actors and so on. Usefull for example at mapchange. You push one event with the notice.. "changemap".. and every actor knows he need to stop moving and every subsystem knows that it does need to stop because of an mapchange and so on ...
It seems to be a bit overkill but it has alot of advantages and worth to use even at early stages. I made the misstake and started using it laterly and now i regret it.
Sorry for the bracing. It's not the regular java standart but more clear i think... Sorry for alot of varargs just like it at that point. Meight be confusing.
Literatur:
Game Coding Complete, Fourth Edition Chapter 11

Pass outer anon class ref to a method in an inner anon class

How to pass outer anon class ref to a method in an inner anon class in Java?
I have a method that makes async call to a server - sendCall(some_args, callback). The callback is represented by anonymous class (let's name it OuterAnon) and contains a method for failure case. Inside this method a message box is created and sendCall() is called each time OK button is pressed. So I need to pass OuterAnon to the method again.
Here is a code to demonstrate what I mean:
private void sendCall(MyData data, OuterAnon<Boolean> callback){/*...*/}
private void myCall(final MyData data) {
sendCall(data, new OuterAnon<Boolean>() {
public void onFailure(Throwable throwable) {
final OuterAnon<Boolean> callback = this; //how to avoid this?
MessageBox.show(throwable.getMessage(), new MessageListener() {
public void process(MessageBox.OnClick action) {
if (action == MessageBox.OnClick.OK) {
sendCall(new MyData("resend?"), callback);
}
}
});
}
}
});
}
As you noticed, I take a ref for callback here:
final OuterAnon<Boolean> callback = this;
and use it here:
sendCall(new MyData("resend?"), callback);
But I want to avoid ref creation and pass callback like:
sendCall(new MyData("resend?"), this); //at the moment we point to MessageListener instead of OuterAnon.
Is there any way to do it in Java?

It's hard for us to fix since you've only shown incomplete code with classes that aren't supplied, so I don't know if this example is syntactically correct. That being said, a refactoring like this may suit your needs:
private void myCall(final MyData data)
{
sendCall(data, new OuterAnon<Boolean>()
{
public void onFailure(Throwable throwable)
{
showErrorMessage(throwable);
}
});
}
private void showErrorMessage(Throwable throwable)
{
MessageBox.show(throwable.getMessage(), new MessageListener()
{
public void process(MessageBox.OnClick action)
{
if (action == MessageBox.OnClick.OK)
{
sendCall(new MyData("resend?"));
}
}
});
}
private void sendCall(MyData data)
{
sendCall(data, this);
}
In general, I think it's a usually good idea to abstract code out of anon inner classes and into their own method on the enclosing class. It's now testable, reusable, and more readable, IMO.

If you really need to specify the onFailure inside the inner class the way you showed the code, and if you need to use that specific reference for callback, and you need to code this way...
Let's answer the question: no.
In my attempts, I've achieved 3 ways to access the anon-inner-least instance inside the anon-inner-most instance, but I think that none satisfies what you expect.
In that case, the anon-inner-most doesn't have a reference to the anon-inner-least: as you said, the this now points to the anon-inner-least.
Also, I tried to search at the java specification, but couldn't find exactly the answer to the question - if someone find the answer there, please contribute.
My try:
import java.util.ArrayList;
import java.util.LinkedList;
public abstract class AnonTest {
public static void main(String[] args) {
new ArrayList<Object>() {
private static final long serialVersionUID = -5986194903357006553L;
{
// initialize inner anon class
add("1");
}
// Way 1
private Object thisReference1 = this;
// Way 2
private Object getThisReference2() {
return this;
}
#Override
public boolean equals(Object obj) {
// Way 3
final Object thisReference3 = this;
new LinkedList<Object>() {
private static final long serialVersionUID = 900418265794508265L;
{
// initialize inner inner anon class
add("2");
}
#Override
public boolean equals(Object innerObj) {
// achieving the instance
System.out.println(thisReference1);
System.out.println(getThisReference2());
System.out.println(thisReference3);
System.out.println(this);
System.out.println();
// achieving the class
System.out.println(thisReference1.getClass());
System.out.println(getThisReference2().getClass());
System.out.println(thisReference3.getClass());
System.out.println(this.getClass());
System.out.println(this.getClass().getEnclosingClass());
return super.equals(innerObj);
}
}.equals("");
return super.equals(obj);
}
}.equals("");
}
}

GWT Editors - how to add N sub-editors of the same type based on a Collection

I have an object, Supply, that can either be an ElecSupply or GasSupply (see related question).
Regardless of which subclass is being edited, they all have a list of BillingPeriods.
I now need to instantiate N number of BillingPeriodEditors based on the contents of that list, and am pretty baffled as to how I should do it.
I am using GWTP. Here is the code of the SupplyEditor I have just got working:
public class SupplyEditor extends Composite implements ValueAwareEditor<Supply>
{
private static SupplyEditorUiBinder uiBinder = GWT.create(SupplyEditorUiBinder.class);
interface SupplyEditorUiBinder extends UiBinder<Widget, SupplyEditor>
{
}
#Ignore
final ElecSupplyEditor elecSupplyEditor = new ElecSupplyEditor();
#Path("")
final AbstractSubTypeEditor<Supply, ElecSupply, ElecSupplyEditor> elecSupplyEditorWrapper = new AbstractSubTypeEditor<Supply, ElecSupply, ElecSupplyEditor>(
elecSupplyEditor)
{
#Override
public void setValue(final Supply value)
{
setValue(value, value instanceof ElecSupply);
if(!(value instanceof ElecSupply))
{
showGasFields();
}
else
{
showElecFields();
}
}
};
#Ignore
final GasSupplyEditor gasSupplyEditor = new GasSupplyEditor();
#Path("")
final AbstractSubTypeEditor<Supply, GasSupply, GasSupplyEditor> gasSupplyEditorWrapper = new AbstractSubTypeEditor<Supply, GasSupply, GasSupplyEditor>(
gasSupplyEditor)
{
#Override
public void setValue(final Supply value)
{
setValue(value, value instanceof GasSupply);
if(!(value instanceof GasSupply))
{
showElecFields();
}
else
{
showGasFields();
}
}
};
#UiField
Panel elecPanel, gasPanel, unitSection;
public SupplyEditor()
{
initWidget(uiBinder.createAndBindUi(this));
gasPanel.add(gasSupplyEditor);
elecPanel.add(elecSupplyEditor);
}
// functions to show and hide depending on which type...
#Override
public void setValue(Supply value)
{
if(value instanceof ElecSupply)
{
showElecFields();
}
else if(value instanceof GasSupply)
{
showGasFields();
}
else
{
showNeither();
}
}
}
Now, as the list of BillingPeriods is a part of any Supply, I presume the logic for this should be in the SupplyEditor.
I got some really good help on the thread How to access PresenterWidget fields when added dynamically, but that was before I had implemented the Editor Framework at all, so I think the logic is in the wrong places.
Any help greatly appreciated. I can post more code (Presenter and View) but I didn't want to make it too hard to read and all they do is get the Supply from the datastore and call edit() on the View.
I have had a look at some examples of ListEditor but I don't really get it!

You need a ListEditor
It depends of how you want to present them in your actual view, but the same idea apply:
public class BillingPeriodListEditor implements isEditor<ListEditor<BillingPeriod,BillingPeriodEditor>>, HasRequestContext{
private class BillingPeriodEditorSource extends EditorSource<BillingPeriodEditor>{
#Override
public EmailsItemEditor create(final int index) {
// called each time u add or retrive new object on the list
// of the #ManyToOne or #ManyToMany
}
#Override
public void dispose(EmailsItemEditor subEditor) {
// called each time you remove the object from the list
}
#Override
public void setIndex(EmailsItemEditor editor, int index) {
// i would suggest track the index of the subeditor.
}
}
private ListEditor<BillingPeriod, BillingPeriodEditor> listEditor = ListEditor.of(new BillingPeriodEditorSource ());
// on add new one ...
// apply or request factory
// you must implement the HasRequestContext to
// call the create.(Proxy.class)
public void createNewBillingPeriod(){
// create a new one then add to the list
listEditor.getList().add(...)
}
}
public class BillingPeriodEditor implements Editor<BillingPeriod>{
// edit you BillingPeriod object
}
Then in you actual editor edit as is in the path Example getBillingPeriods();
BillingPeriodListEditor billingPeriods = new BillingPeriodListEditor ();
// latter on the clickhandler
billingPeriods.createNewBillingPeriod()
You are done now.

How to get reference to an anonymous object 2 levels up

I have code like this:
TextBox txt = new TextBox(){
public void onLoad(){
this.addFocusHandler(new FocusHandler(){
//some codes here
//if I use "this" keyword, it refers to the handler, but how can I get a reference to the textbox?
});
}
};
Question is embedded in the position.
Edit:
In respect to the answers, the creation of a pre-defined reference works for this situation, but this apparently lost (or at least reduce) the benefits of anonymous object/function.
I hope to find a way without creating a new reference. Rather just to get the reference from that scope.
After all the answers, here is a conclusion:
Reflection does not work in GWT. (at least I did not succeed) obj.getClass() works, but others like getMethods() or getEnclosingClass() don't work.
The way to get a reference can either be declaring a reference in the right scope, or get a higher level object reference and reference downwards. I prefer the latter simply because you don't need to create a new variable.

TextBox txt = new TextBox(){
public void onLoad(){
final TextBox finalThis = this;
this.addFocusHandler(new FocusHandler(){
finalThis.doSomething();
);
}
};

The enclosing instance of a non-static inner class (anonymous or named) in Java is available as ClassName.this, i.e.
TextBox txt = new TextBox(){
public void onLoad(){
this.addFocusHandler(new FocusHandler(){
doSomethingCleverWith(TextBox.this);
});
}
};

This has worked for me in the past. It works in client side js too. Here is a reference to more detail
What is the difference between Class.this and this in Java
public class FOO {
TextBox txt = new TextBox(){
public void onLoad(){
this.addFocusHandler(new FocusHandler(){
#Override
public void onFocus(FocusEvent event) {
FOO.this.txt.setHeight("100px");
}
});
}
};
}

This may work for you:
TextBox txt = new TextBox(){
public void onLoad(){
final TextBox ref = this;
this.addFocusHandler(new FocusHandler(){
public void doSomething(){
//some codes
ref.execute();
}
});
}
};
But I prefer to migrate inner classes to named classes:
public class Test {
public void demo(){
TextBox txt = new TextBox(){
public void onLoad(){
this.addFocusHandler(new DemoFocusHandler(this));
}
};
}
}
External FocusHandler:
public class DemoFocusHandler extends FocusHandler {
private TextBox textBox;
public DemoFocusHandler(TextBox textBox){
this.textBox = textBox;
}
public void doSomething(){
//some codes
textBox.execute();
}
}

If gwt supported reflection you could do something along the lines of this:
final TextBox txt = new TextBox() {
public void onLoad() {
final Object finalThis = this;
this.addFocusHandler(new FocusHandler() {
#Override
public void onFocus(FocusEvent event) {
try {
Method method= finalThis.getClass().getMethod("getVisibleLength");
method.invoke(finalThis);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
};
Without reflection the existing answers are you best bet. There are two gwt reflection projects gwt reflection and gwt-preprocessor both are in beta and I have not tried them.

ComboBoxModel events not working

I seem not to grasp the concept of Events and such. After reading a while on how to implement the listeners and such I came across the Java tutorial saying I should extend AbstractListModel to get the data event firing. For some reason it still doesn't work.
Is there anything I'm doing wrong?
And what kind of code is expected at addListDataListener(ListDataListener l) for it to work? Since I don't understand that either.
public class CarComboBox extends AbstractListModel<Object> implements ComboBoxModel<Object> {
private JdbcRowSet jdbc;
private int size = 0;
private String selection;
public CarComboBox() {
try {
jdbc = new Query().getCarInfo();
jdbc.beforeFirst();
while (jdbc.next()) {
size++;
}
jdbc.beforeFirst();
}
catch (SQLException ex) {
System.err.println(ex.toString());
}
}
#Override
public void setSelectedItem(Object anItem) {
selection = (String) anItem;
}
#Override
public Object getSelectedItem() {
return selection;
}
#Override
public void addListDataListener(ListDataListener l) {
}
#Override
public void removeListDataListener(ListDataListener l) {
}
#Override
public int getSize() {
return size;
}
#Override
public String getElementAt(int index) {
try {
jdbc.absolute(index + 1);
return jdbc.getString(2);
}
catch (SQLException ex) {
System.out.println(ex.toString());
}
return null;
}
}
And to add a listener to the CarComboBox I do:
CarComboBox ccb = new CarComboBox();
ccb.addListDataListener(new ListDataListener()

I'm guessing that you are using the official tutorial.
However you should not touch ListModel and ComboBoxModel. Those are more advanced features you probably do not need.
The 4 examples in the tutorial do NOT use ListModel and ComboBoxModel.
If you use a standard JComboBox (no ListModel or ComboBoxModel), what happens is that when someone makes a selection, an ActionEvent is fired. This event is magically fired by Swing; you don't have to worry about how it is generated. However what is your responsibility is to have some (zero, one or more) objects being able to receive and do something about the ActionEvent:
public class MyClass implements ActionListener {
JComboBox comboBox = ...;
...
// You must register explicitly every ActionListener that you
// want to receive ActionEvent's from comboBox.
// Here we register this instance of MyClass.
comboBox.addActionListener(this);
...
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() instanceof JComboBox) {
System.out.println("MyClass registered an ActionEvent from a JComboBox.");
System.out.println("Selected: " +
((JComboBox) e.getSource()).getSelectedItem());
}
}
}
Note that if you don't have any other ActionEvent's fired by different Swing components you
can skip the if (e.getSource() instanceof JComboBox) since you know your ActionEvent always comes from a JComboBox.
In my example the JComboBox is inside MyClass, but it does not have to be:
JComboBox comboBox = ...;
MyClass myClass = ...;
comboBox.addActionListener(myClass);
...
comboBox.addActionListener(someOtherActionListener);

You don't need to override addListDataListener() and removeListDataListener() method. The AbstractListModel already take care of the listeners. Here is the implementation of AbstractListModel.addListDataListener():
public void addListDataListener(ListDataListener l) {
listenerList.add(ListDataListener.class, l);
}
The idea of abstract classes is that they do most of the work for you. Usually you only need to implement abstract methods.

XXListener and XXModel are different sides of the coin: the former is the observer to the latter which is the observable. The listener registers itself to the model when it wants to get notified on changes. It's the responsibility of the model to
manage its listeners (that's typically handled already by the AbstractXXModel, as already explained by #userWhateverNumber ;)
fire the notifications if appropirate: that's the part a custom model must take over, in your case
like
#Override
public void setSelectedItem(Object item) {
selection = item;
fireContentChanged(this, -1, -1);
}
Arguably (there are personal preferences around :-) you often don't need custom model implementations but can just as well re-use the provided DefaultXXModels. In your context and assuming the content of the resultset is immutable it might be an option to fill the default model with the data at construction time, like
DefaultComboBoxModel model = new DefaultComboBoxModel();
forEachRowInResultSet {
model.addElement(resultSet.getString(2));
}
If, on the other hand, the content changes then your model implementation is invalid anyway: the model must notify its listeners whenever something had changed
Object one = model.getElementAt(index);
Object other = model.getElementAt(index)
if (!one.equals(other)) {
listener must have received a contentsChanged
}