GPS location updates on Android using AlarmManager inside the service

Question

I read a lot of questions here, but couldn't figure out what the problem is.

I am writing a field service application for Android. In one of the operations (MyActivity.java) I have two buttons: "Start" and "Stop".

When the field worker clicks on the start, I need to get his current location using GPS and send it to the server at certain intervals (let's say that it will be 5 minutes by default, here I set it to 20 seconds for testing). The client wants this to show how long workers spend time on traffic, traffic in my city (Istanbul) is a mess.

I have an AlarmManager in my activity, when the start button is pressed, the alarm is set by AlarmManager.setRepeating() to start the service (ServiceClass.java).

 Intent intent = new Intent (MyActivity.this, ServiceClass.class); mPendingIntent = PendingIntent.getService(MyActivity.this, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT); mAlarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE); mAlarmManager.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(), 20*1000, mPendingIntent); 

I cancel the alarm using the "Stop" button.

It works fine so far, Service begins. Its methods onCreate() , onStart() and onDestroy() . But I can’t find a place. I am not working on a real device, so I use DDMS to send places. But the application skips this step and prints the longitude and latitude of my location as Lon: 0 Lat: 0.

Here's the code inside the service:

 public void onStart(Intent intent, int startId) { super.onStart(intent, startId); Log.d("Testing", "Service got started, calling location updates:"); mLocationManager.requestSingleUpdate(mCriteria, mLocationListener, getMainLooper()); Log.i("TESTING LOCATION UPDATE: LOCATION:", "\nLat:" + mLatitude + " Lon:" + mLongitude); stopSelf(startId); Log.d("Testing", "Service Stopped!"); 

And finally, here is my LocationListener:

  mLocationListener = new LocationListener() { @Override public void onLocationChanged(Location location) { if(location != null){ mLatitude = location.getLatitude(); mLongitude = location.getLongitude(); Log.i("onLocationChanged(Location location)", "Lat:"+mLatitude + " Lon:" + mLongitude); } 

I also caught my eye when I ran the code:

 mLocationProvider = mLocationManager.getBestProvider(mCriteria, true); Log.i("BEST PROVIDER IS:", mLocationProvider); 

It says BEST PROVIDER: gps. But this log inside onProviderEnabled () is never displayed in logcat.

 @Override public void onProviderEnabled(String s) { Log.v("onProviderEnabled", "ENABLED"); } 

Two things to add if I use:

 mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mLocationListener); 

it doesn't work either.

This works, and I can get LastKnownLocation:

 Location lastKnown = mLocationManager.getLastKnownLocation( LocationManager.GPS_PROVIDER); 

First of all, is this a good approach for this? If this is, please check what I am missing. If this is not the case, can you tell me how I can implement this better?

Thanks.:)

Answer 1

First, you cannot register for location updates, and then disable the service. At best, you will leak threads. In the worst case, Android will terminate your process (thinking that nothing is working in it) and you will not receive the update. In addition, GPS takes some time to warm up, so you cannot fix the error within 20 seconds, especially in urban environments. In addition, you must ensure that the device does not work while you are trying to compile a patch.

As a result, obtaining periodic corrections of a location in the background is a rather difficult task.

I wrote a canceled LocationPoller now to try to solve this problem, and another developer forked and expanded it . You can try the plug or just use it as a source of ideas.

Answer 2

try the following:

 AlarmManager.setRepeating(AlarmManager.RTC_WAKEUP，，，）; 

I do to get one current location with GPS, but my project works every 10 seconds. I have no idea. And my code is:

 AlarmManager.setRepeating(AlarmManager.RTC_WAKEUP,System.currentTimeMillis(),6000000,pi);