Android Open Source - BusFollower Fetch Trips Task

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License

The source code is released under:

GNU General Public License

Java Source Code

/*
 * Copyright 2012 Clayton Smith//from w  w  w  .ja  va  2s.  c  o m
 *
 * This file is part of Ottawa Bus Follower.
 *
 * Ottawa Bus Follower 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, or (at
 * your option) any later version.
 *
 * Ottawa Bus Follower 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 Ottawa Bus Follower; see the file COPYING.  If not, see
 * <http://www.gnu.org/licenses/>.
 */

package net.argilo.busfollower;

import java.io.IOException;

import net.argilo.busfollower.ocdata.GetNextTripsForStopResult;
import net.argilo.busfollower.ocdata.OCTranspoDataFetcher;
import net.argilo.busfollower.ocdata.Route;
import net.argilo.busfollower.ocdata.RouteDirection;
import net.argilo.busfollower.ocdata.Stop;
import net.argilo.busfollower.ocdata.Util;

import org.xmlpull.v1.XmlPullParserException;

import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.AsyncTask;

public class FetchTripsTask extends AsyncTask<RecentQuery, Void, GetNextTripsForStopResult> {
    Context activityContext = null;
    Context applicationContext = null;
    SQLiteDatabase db = null;
    ProgressDialog progressDialog = null;
    private Route route = null;
    private String errorString = null;
    OCTranspoDataFetcher dataFetcher = null;
    private boolean finished = false;
    
    public FetchTripsTask(Context context, SQLiteDatabase db) {
        super();
        activityContext = context;
        applicationContext = context.getApplicationContext();
        this.db = db;
    }
    
    @Override
    protected void onPreExecute() {
        progressDialog = createProgressDialog();
    }

    @Override
    protected GetNextTripsForStopResult doInBackground(RecentQuery... query) {
        Stop stop = query[0].getStop();
        route = query[0].getRoute();
        GetNextTripsForStopResult result = null;
        try {
            dataFetcher = new OCTranspoDataFetcher(applicationContext, db);
            result = dataFetcher.getNextTripsForStop(stop.getNumber(), route.getNumber());
            errorString = Util.getErrorString(applicationContext, result.getError());
            if (errorString == null) {
                // Check whether there are any trips to display, since there's no
                // point going to the map screen if there aren't.
                for (RouteDirection rd : result.getRouteDirections()) {
                    if (rd.getDirection().equals(route.getDirection())) {
                        if (rd.getTrips().isEmpty()) {
                            errorString = applicationContext.getString(R.string.no_trips);
                        }
                    }
                }
            }
        } catch (IOException e) {
            errorString = applicationContext.getString(R.string.server_error);
        } catch (XmlPullParserException e) {
            errorString = applicationContext.getString(R.string.invalid_response);
        } catch (IllegalArgumentException e) {
            errorString = e.getMessage();
        } catch (IllegalStateException e) {
            // The user cancelled the request by pressing the back button.
        }
        return result;
    }
    
    @Override
    protected void onPostExecute(GetNextTripsForStopResult result) {
        finished = true;
        if (activityContext == null) {
            return;
        }
        progressDialog.dismiss();
        if (isCancelled()) {
            return;
        }
        if (errorString != null) {
            AlertDialog.Builder builder = new AlertDialog.Builder(activityContext);
            builder.setTitle(R.string.error)
            .setMessage(errorString)
            .setNegativeButton(applicationContext.getString(R.string.ok), new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    dialog.cancel();
                }
            });
            AlertDialog alert = builder.create();
            alert.show();
        } else {
            if (activityContext instanceof BusFollowerActivity) {
                // Don't launch the BusFollowerActivity if it's the one that
                // requested the update. Just display the update.
                ((BusFollowerActivity) activityContext).setResult(result);
            } else {
                Intent intent = new Intent(activityContext, BusFollowerActivity.class);
                intent.putExtra("result", result);
                intent.putExtra("route", route);
                activityContext.startActivity(intent);
            }
        }
    }
    
    public void setActivityContext(Context context) {
        activityContext = context;
        if (context == null) {
            progressDialog = null;
        } else {
            if (!finished && !isCancelled()) {
                progressDialog = createProgressDialog();
            }
        }
    }
    
    private ProgressDialog createProgressDialog() {
        ProgressDialog progressDialog = ProgressDialog.show(activityContext, "", applicationContext.getString(R.string.loading), true, true, new DialogInterface.OnCancelListener() {
            @Override
            public void onCancel(DialogInterface dialog) {
                if (dataFetcher != null) {
                    cancel(false);
                    dataFetcher.abortRequest();
                }
            }
        });
        return progressDialog;
    }
}

Java Source Code List

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