Comment utiliser MyAsyncCallback?

Version imprimable

Bonsoir,

voilà j'ai créer un AsyncCallBack (MyAsyncCallback):

Code:

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package fr.unice.xmlteam.client;
 
import com.google.gwt.user.client.rpc.AsyncCallback;
 
public class MyAsyncCallback<T> implements AsyncCallback<T> {
 
    private final AjaxHandler handler;
    private final AsyncCallback<T> delegate;
 
    public MyAsyncCallback(AjaxHandler handler, AsyncCallback<T> asyncCallBack) {
        this.handler = handler;
        this.delegate = asyncCallBack;
        handler.onStart();
    }
 
    public void onFailure(Throwable caught) {
        handler.onComplete();
        handler.onError();
        this.delegate.onFailure(caught);
    }
 
    public void onSuccess(T result) {
        handler.onComplete();
        handler.onSuccess();
        this.delegate.onSuccess(result);
    }
 
}

qui implémente AsyncCallback et qui utilise un AjaxHandler:

Code:

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package fr.unice.xmlteam.client;
 
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.LayoutPanel;
import com.google.gwt.user.client.ui.RootPanel;
 
public class MyAjaxHandler implements AjaxHandler {
 
    private Label busyLabel = new Label("Loading...");
    private Label errorLabel = new Label("Error");
    private LayoutPanel container = new LayoutPanel();
 
    private static MyAjaxHandler instance;
 
    private MyAjaxHandler() {
 
    }
 
    public void onComplete() {
        container.clear();
        RootPanel.get().remove(container);
    }
 
    public static MyAjaxHandler getInstance() {
        if(instance == null) instance = new MyAjaxHandler();
        return instance;
    }
 
    public void onError() {
        container.add(errorLabel);
    }
 
    public void onStart() {
        container.clear();
        container.add(busyLabel);
        RootPanel.get().add(container);
    }
 
    public void onSuccess() {
        onComplete();
    }
 
}

cet MyAjaxHandler hérite de AjaxHandler(Une interface):

Code:

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package fr.unice.xmlteam.client;
 
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.LayoutPanel;
import com.google.gwt.user.client.ui.RootPanel;
 
public class MyAjaxHandler implements AjaxHandler {
 
    private Label busyLabel = new Label("Loading...");
    private Label errorLabel = new Label("Error");
    private LayoutPanel container = new LayoutPanel();
 
    private static MyAjaxHandler instance;
 
    private MyAjaxHandler() {
 
    }
 
    public void onComplete() {
        container.clear();
        RootPanel.get().remove(container);
    }
 
    public static MyAjaxHandler getInstance() {
        if(instance == null) instance = new MyAjaxHandler();
        return instance;
    }
 
    public void onError() {
        container.add(errorLabel);
    }
 
    public void onStart() {
        container.clear();
        container.add(busyLabel);
        RootPanel.get().add(container);
    }
 
    public void onSuccess() {
        onComplete();
    }
 
}

Je voudrai utiliser cela pour afficher quelque chose comme "Chargement en cours" par exemple mais je ne sais pas du tout comment l'utiliser.

*Merci*

14/12/2010, 23h22
M4v3rick

Comment utilises-tu ce AsyncCallBack ?

Normalement, tu peux écrire ton message de progression juste avant de faire l'appel à ton service "RPC" et changer ce message dans la méthode "onSuccess" de cet AsyncCallBack.

Comme c'est un appel asynchrone,
Ton message va s'afficher et quand le résultat du service arrivera au client, tu pourras afficher un autre message ou effacer le précédent - traiter ton résultat dans la méthode AsyncCallBack.onSucess().

Tu as un exemple:

Code:

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// This code is called before the RPC starts
 //
  if (startRow == lastStartRow) {
    ...
  }
 
  // Invoke the RPC call, implementing the callback methods inline:
  //
  calService.getPeople(startRow, maxRows, new AsyncCallback<Person[]>() {
 
    // When the RPC returns, this code will be called if the RPC fails
    public void onFailure(Throwable caught) {
       statusLabel.setText("Query failed: " + caught.getMessage());
       acceptor.failed(caught);
    }
 
    // When the RPC returns, this code is called if the RPC succeeds
    public void onSuccess(Person[] result) {
      lastStartRow = startRow;
      lastMaxRows = maxRows;
      lastPeople = result;
      pushResults(acceptor, startRow, result);
      statusLabel.setText("Query reutrned " + result.length + " rows.");
    }
  });
 
  // The above method call will not block, but return immediately.
  // The following code will execute while the RPC is in progress, 
  // before either of onFailure() or onSuccess() are executed.
  //
  statusLabel.setText("Query in progress...");
  ...

dispo à la page suivante:
http://code.google.com/webtoolkit/do...eRPCDeployment