Android Open Source - GeoTagger Alert Service

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Back to project page GeoTagger.
License

The source code is released under:
GNU General Public License
If you think the Android project GeoTagger listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
Java Source Code

package horizon.geotagger;
//ww  w . j a  v  a2  s  . c  om
import horizon.android.logging.Logger;
import horizon.geotagger.model.Tag;
import horizon.geotagger.view.TagView;

import java.util.ArrayList;
import java.util.Iterator;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.map.ObjectMapper;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;

public class AlertService
extends Service
implements Runnable
{
  private static final Logger logger = Logger.getLogger(AlertService.class);
  
  private static final int LOCATION_UPDATE_WHAT = 5601;
  
  private static final int NOTIFICATION_ID = 1001;
  
  private final Notification notification = new Notification();
  {
    notification.icon = R.drawable.icon;
    notification.defaults = Notification.DEFAULT_VIBRATE;
    notification.flags = Notification.FLAG_AUTO_CANCEL;
  }
  
  private Handler messageHandler;
  
  private LocationManager locationManager;
  
  private NotificationManager notificationManager;
  
  // N.B. Part of a very naive thread signalling mechanism
  private boolean processing = false;
    
  @Override
  public IBinder onBind(Intent intent)
  {
    return null;
  }

  @Override
  public void onStart(Intent intent, int startId)
  {
    super.onStart(intent, startId);
    new Thread(this).start();
    
    notificationManager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
        
    locationManager = (LocationManager)getSystemService(LOCATION_SERVICE);
    locationManager.requestLocationUpdates(
        LocationManager.GPS_PROVIDER, 60000, 1,
        new LocationListener()
        {
          private Location lastLocation;
          
          @Override
          public void onStatusChanged(String provider, int status, Bundle extras) { }
          @Override
          public void onProviderEnabled(String provider) { }
          @Override
          public void onProviderDisabled(String provider) { }
          @Override
          public void onLocationChanged(Location location) 
          {
            // Enforce a minimum 30 second interval between
            // updates or a minimum 5 meter travel distance
            if(lastLocation != null)
            {
              double distance = GeoUtils.distance(
                  lastLocation.getLatitude(),
                  lastLocation.getLongitude(),
                  location.getLatitude(),
                  location.getLongitude());
              long time = location.getTime() - lastLocation.getTime();
              if(distance < 5D && time < 30000)
                return;
            }
            
            lastLocation = location;
            Message msg = Message.obtain(
                messageHandler,
                LOCATION_UPDATE_WHAT,
                location);
            messageHandler.dispatchMessage(msg);            
          }
        });  
  }

  @Override
  public void run()
  {
    Looper.prepare();
    
    messageHandler = new Handler()
    {
      @Override
      public void handleMessage(final Message msg)
      {
        if(msg.what != LOCATION_UPDATE_WHAT)
        {
          super.handleMessage(msg);
          return;
        }
        
        if(hasMessages(LOCATION_UPDATE_WHAT))
          return;
        
        if(processing)
          return;
        
        new Thread(new Runnable()
        {  
          @Override
          public void run()
          {
            updateWrapper((Location)msg.obj);            
          }
        }).start();
      }  
    };
    
    Looper.loop();    
  }
  
  private void updateWrapper(Location location)
  {
    processing = true;
    try
    {
      update(location);
    }
    catch(RuntimeException e)
    {
      throw e;
    }
    finally
    {
      processing = false;
    }
  }
  
  private void update(Location location)
  {  
    ArrayList<Tag> tags = getTags(location);
    
    if(tags.size() == 0)
    {
      notificationManager.cancel(NOTIFICATION_ID);
      return;
    }
    
    Intent view = new Intent(this, TagView.class);
    view.putParcelableArrayListExtra(TagView.TAG_LIST, tags);
    PendingIntent content = PendingIntent.getActivity(this, 0, view, PendingIntent.FLAG_UPDATE_CURRENT);
    
    notification.tickerText = "There are " + tags.size() + " geonotes here for you to view"; 
    notification.number = tags.size();
    notification.setLatestEventInfo(
        getApplicationContext(),
        "GeoTagger",
        "There are " + tags.size() + " geonotes here for you to view",
        content);
    
    
    notificationManager.notify(NOTIFICATION_ID, notification);
  }
  
  private ArrayList<Tag> getTags(Location location)
  {
    HttpClient client = new DefaultHttpClient();
    HttpGet get = new HttpGet("http://horizon-geotagger.appspot.com/tagsAtPoint?latitude=" +
        + location.getLatitude() 
        + "&longitude=" + location.getLongitude() 
        + "&accuracy=" + location.getAccuracy());
    HttpResponse response;
    try 
    {
      response = client.execute(get);
      StatusLine sl = response.getStatusLine();
      if(sl.getStatusCode() != HttpStatus.SC_OK)
      {
        logger.warn("Unable to get tags from cloud: " + sl.getReasonPhrase());
        get.abort();
        return new ArrayList<Tag>();
      }
      
      HttpEntity entity = response.getEntity();
      if(entity == null)
        return new ArrayList<Tag>();
      
      ObjectMapper mapper = new ObjectMapper();
      JsonNode node = mapper.readTree(EntityUtils.toString(entity, "UTF-8"));
      ArrayList<Tag> tags = new ArrayList<Tag>();
      
      if(!node.isArray() || node.isNull())
        return tags;
      
      for(Iterator<JsonNode> i = node.getElements(); i.hasNext(); )
        tags.add(mapper.treeToValue(i.next(), Tag.class));
      
      return tags;
    }
    catch(Exception e)
    {
      logger.error(e.getMessage(), e);
      return new ArrayList<Tag>();
    }
  }
}
Java Source Code List
