Android Open Source - Go2-Rennes Background Task

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License

The source code is released under:

GNU General Public License

Java Source Code

/*******************************************************************************
 * Copyright (c) 2011 Michel DAVID mimah35-at-gmail.com
 * // w w w  .ja  v  a2s . com
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
package fr.gotorennes.util;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnCancelListener;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import fr.gotorennes.R;

public abstract class BackgroundTask<T> {

  private boolean showPopup;
  private String message;
  private AsyncTask<Void,String,T> task;
  private List<Handler> handlers = new ArrayList<Handler>();

  public BackgroundTask() {
    this(true);
  }

  public BackgroundTask(String message) {
    this(message, true);
  }

  public BackgroundTask(boolean showPopup) {
    this(null, showPopup);
  }

  public BackgroundTask(String message, boolean showPopup) {
    this.message = message;
    this.showPopup = showPopup;
  }

  public void addHandler(Handler handler) {
    handlers.add(handler);
  }
  
  protected abstract T execute();

  protected abstract void callback(T result);
  
  public void start(Activity context) {

    if(message == null) {
      message = context.getString(R.string.chargement);
    }
    
    final ProgressDialog waitDialog = showPopup ? ProgressDialog.show(context, context.getString(R.string.titre), message, true, true, new OnCancelListener() {
      
      @Override
      public void onCancel(DialogInterface dialog) {
        if(task != null){
          task.cancel(true);
        }
        task.cancel(true);
      }
    }) : null;
    
    task = new AsyncTask<Void, String, T>() {

      @Override
      protected T doInBackground(Void... params) {
        try {
          return BackgroundTask.this.execute();
        }
        catch(Throwable ex) {
          Log.e("GoToRennes", ex.getMessage(), ex);
        }
        return null;
      }

      @Override
      protected void onPostExecute(T result) {
        callback(result);
        if (waitDialog != null) {
          try {
            waitDialog.dismiss();
          }
          catch(Exception ex) {
            //Cas trange sur certains tel
            // http://stackoverflow.com/questions/2745061/java-lang-illegalargumentexception-view-not-attached-to-window-manager
          }
        }
        
        for(Handler handler : handlers) {
          Message message = new Message();
          message.obj = result;
          handler.dispatchMessage(message);
        }
      }
    };
    task.execute();
  }
}

Java Source Code List

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