Android Open Source - HarleyDroid Harley Droid G P S

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License

The source code is released under:

GNU General Public License

Java Source Code

//
// HarleyDroid: Harley Davidson J1850 Data Analyser for Android.
///*from  www  .j a v a 2  s  . c om*/
// Copyright (C) 2010-2012 Stelian Pop <stelian@popies.net>
//
// 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, or
// (at your option) any later version.
//
// 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 org.harleydroid;

import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.location.LocationProvider;
import android.os.Bundle;
import android.util.Log;

public class HarleyDroidGPS implements LocationListener
{
  private static final boolean D = false;
  private static final String TAG = HarleyDroidGPS.class.getSimpleName();

  private LocationManager mLocationManager;
  private Location mCurrentBestLocation;

  public HarleyDroidGPS(Context context) {
    mLocationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
  }

  public void start() {
    if (D) Log.d(TAG, "start()");

    mCurrentBestLocation = null;
    mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
  }

  public void stop() {
    if (D) Log.d(TAG, "stop()");

    mLocationManager.removeUpdates(this);
  }

  public String getLocation() {
    if (D) Log.d(TAG, "getLocation() = " + mCurrentBestLocation);

    if (mCurrentBestLocation == null)
      return ",,";

    return Double.toString(mCurrentBestLocation.getLongitude()) + "," +
         Double.toString(mCurrentBestLocation.getLatitude()) + "," +
         Double.toString(mCurrentBestLocation.getAltitude());
  }

  private static final int TWO_MINUTES = 1000 * 60 * 2;

  /** Determines whether one Location reading is better than the current Location fix
   * @param location  The new Location that you want to evaluate
   * @param currentBestLocation  The current Location fix, to which you want to compare the new one
   */
  protected boolean isBetterLocation(Location location, Location currentBestLocation) {
    if (currentBestLocation == null) {
      // A new location is always better than no location
      return true;
    }

    // Check whether the new location fix is newer or older
    long timeDelta = location.getTime() - currentBestLocation.getTime();
    boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
    boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
    boolean isNewer = timeDelta > 0;

    // If it's been more than two minutes since the current location, use the new location
    // because the user has likely moved
    if (isSignificantlyNewer) {
      return true;
      // If the new location is more than two minutes older, it must be worse
    } else if (isSignificantlyOlder) {
      return false;
    }

    // Check whether the new location fix is more or less accurate
    int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
    boolean isLessAccurate = accuracyDelta > 0;
    boolean isMoreAccurate = accuracyDelta < 0;
    boolean isSignificantlyLessAccurate = accuracyDelta > 200;

    // Check if the old and new location are from the same provider
    boolean isFromSameProvider = isSameProvider(location.getProvider(),
        currentBestLocation.getProvider());

    // Determine location quality using a combination of timeliness and accuracy
    if (isMoreAccurate) {
      return true;
    } else if (isNewer && !isLessAccurate) {
      return true;
    } else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
      return true;
    }
    return false;
  }

  /** Checks whether two providers are the same */
  private boolean isSameProvider(String provider1, String provider2) {
    if (provider1 == null) {
      return provider2 == null;
    }
    return provider1.equals(provider2);
  }

  public void onLocationChanged(Location location) {
    if (D) Log.d(TAG, "onLocationChanged(" + location + ")");

    if ((mCurrentBestLocation == null) ||
        (isBetterLocation(location, mCurrentBestLocation)))
      mCurrentBestLocation = location;
  }

  public void onStatusChanged(String provider, int status, Bundle extras) {
    if (D) Log.d(TAG, "onStatusChanged(" + status + ")");

    if (status == LocationProvider.OUT_OF_SERVICE)
      mCurrentBestLocation = null;
  }

  public void onProviderEnabled(String provider) {
    if (D) Log.d(TAG, "onProviderEnabled()");

    mCurrentBestLocation = null;
  }

  public void onProviderDisabled(String provider) {
    if (D) Log.d(TAG, "onProviderDisabled()");

    mCurrentBestLocation = null;
  }
};

Java Source Code List

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