I'm trying to get the location updates running in a background service. The service is running a workerthread of its own doing a lot of other stuff already, like socket communication. I'd like it to also handle location updates but this seems to only work on an activity. As far as I can read this is due to the message loop missing on a workerthread. I think I need to use Looper.prepare() somewhere, but maybe I need another thread just to handle locations requests? I can't seem to get the emulator to respond to any geo fix events, so I must be doing something wrong.
Below is the service code, stripped for all the non-relevant parts.
public class MyService extends Service implements LocationListener {
private Thread runner;
private volatile boolean keepRunning;
private LocationManager locationManager = null;
#Override
public void onCreate() {
keepRunning = true;
runner = new Thread(null, new Runnable() {
public void run() { workerLoop(); }
});
runner.start();
startGps();
}
#Override
public void onDestroy() {
keepRunning = false;
runner.interrupt();
}
private void workerLoop() {
//Looper.myLooper(); How does this work??
//Looper.prepare();
// Main worker loop for the service
while (keepRunning) {
try {
if (commandQueue.notEmpty()) {
executeJob();
} else {
Thread.sleep(1000);
}
} catch (Exception e) {
}
}
stopGps();
}
public void onLocationChanged(Location location) {
// Doing something with the position...
}
public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
private void startGps() {
if (locationManager == null)
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
if (locationManager != null) {
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(true);
criteria.setCostAllowed(false);
criteria.setSpeedRequired(true);
String provider = locationManager.getBestProvider(criteria, true);
if (provider != null)
locationManager.requestLocationUpdates(provider, 10, 5, (LocationListener) this);
}
}
private void stopGps() {
if (locationManager != null)
locationManager.removeUpdates((LocationListener) this);
locationManager = null;
}
}
The LocationListener doesn't care whether it is in the context of an activity or a service.
You want to use the location uodates in your workerLoop(), right? The location updates (the call to the LocationListener) and the workerLoop() are both acting independently from each other. To get the location update to the workerLoop() you need to join the two threads. One method to do this is to use the blackboard pattern: The LocationListener writes the new location to a field of your class (this is easy since both are in the context of the same class):
private Location blackboard = null;
public void onLocationChanged(final Location location) {
if( location != null )
this.blackboard = location;
}
private void workerLoop() {
...
if( this.blackboard != null ) {
final Location locationUpdate = this.blackboard;
this.blackboard = null;
// .. do something with the location
}
...
}
With the above code you may get race conditions when the LocationListener writes to the blackboard while the workerLoop() is reading or erasing the location. This can be solved by surrounding the access to the blackboard by a synchronized block like this:
synchronized(this) {
this.blackboard = location
}
and likewise in the workerLoop(), and we must declare the blackboard volatile:
private volatile Location blackboard = null;
Alternatively you may use a Lock, confer to the docs for more details: http://docs.oracle.com/javase/tutorial/essential/concurrency/newlocks.html
Related
I am not getting GPS location in my code, while Google maps is showing current location and even its updating, I am starting a service, inside service registering locationListener to the locationManager, handling onLocationChanged callback method, doing entry in the AndroidManifest.xml even. The logs onCreate methods is showing.
below is my code, could you guys please let me know where i am doing wrong...
public class LocationService extends Service implements LocationListener {
private static final long MIN_TIME_INTERVAL_FOR_GPS_LOCATION = 100;
private static final float MIN_DISTANCE_INTERVAL_FOR_GPS_LOCATION = 1.0f;
private static String TAG = LocationService.class.getSimpleName();
private LocationManager locationManager;
private static Location mCurrentLocation;
#Override
public IBinder onBind(Intent intent) {
return null;
}
#Override
public void onCreate() {
super.onCreate();
Log.i(TAG, "onCreate...");
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_INTERVAL_FOR_GPS_LOCATION, MIN_DISTANCE_INTERVAL_FOR_GPS_LOCATION, this);
mCurrentLocation = getBestLocation();
}
private Location getBestLocation() {
Log.i(TAG, "getBestLocation...");
Location location_gps = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
Location location_network = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
// If both are available, get the most recent
if (location_gps != null && location_network != null) {
return (location_gps.getTime() > location_network.getTime()) ? location_gps : location_network;
} else if (location_gps == null && location_network == null) {
return null;
} else {
return (location_gps == null) ? location_network : location_gps;
}
}
#Override
public void onLocationChanged(Location location) {
Log.i(TAG, "onLocationChanged...");
Toast.makeText(LocationService.this, "Location Found", Toast.LENGTH_SHORT).show();
mCurrentLocation = location;
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
public static Location getmCurrentLocation() {
return mCurrentLocation;
}
public static void setmCurrentLocation(Location mCurrentLocation) {
LocationService.mCurrentLocation = mCurrentLocation;
}
#Override
public void onDestroy() {
super.onDestroy();
Log.i(TAG, "onDestroy...");
locationManager.removeUpdates(this);
}
}
Your locationManager called requestLocationUpdates using GPS provider only.
I think your device could not catch GPS satellite signal, in-door sate.
So, you should call requestLocationUpdates using Network provider too.
Next two links are may helpful to you.
http://developer.android.com/guide/topics/location/strategies.html
http://developer.android.com/training/location/receive-location-updates.html
I have a service that needs to know the phone's location. The main activities of the service are carried out in a thread as follows (with processing stuff removed:
Semaphore locationAcquired = new Semaphore(1);
LocationFinder finder;
...
public void run() {
delaySeconds = 60;
Looper.prepare();
while (true) {
try {
finder.StartFinder();
locationAcquired.acquire();
// do some stuff...
} catch (InterruptedException e) {
if (isDestroy) {
Log.d(TAG, "Closing Monitor Thread");
break;
} // else just wake up and process the location
} catch (Exception e) {
e.printStackTrace();
}
} // end while
} // end run
The LocationFinder class implementation (again, slightly simplified):
package com.ksdagile.opengate;
import...
public class LocationFinder {
public static final int ONE_SECOND = 1000;
LocationListener locationListener;
String provider = LocationManager.PASSIVE_PROVIDER; // passive by default
LocationManager locationManager;
public Location currentLocation;
long updateSeconds;
private boolean isLooking = false;
OpenGateService openGateService;
public LocationFinder(LocationManager _lm, OpenGateService _openGateService) {
openGateService = _openGateService;
locationManager = _lm;
// initialize with whatever location might be available
currentLocation = locationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
// A new location update is received. Do something useful with it. In this case,
// we're sending the update to a handler which then updates the UI with the new
// location.
currentLocation = location;
String newLoc = String.format("Found new Location lat:%.2f long:%.2f", currentLocation.getLatitude(), currentLocation.getLongitude());
Log.d(getClass().getName(), newLoc);
openGateService.locationAcquired.release();
}
// simple implementations of onProvider<> etc.
};
}
public void SetProvider(boolean isActive) {
if (isActive)
provider = LocationManager.GPS_PROVIDER;
else
provider = LocationManager.PASSIVE_PROVIDER;
}
public void SetFrequency(long delay) {
updateSeconds = delay;
}
public void StartFinder() {
if (!isLooking) {
isLooking = true;
locationManager.requestLocationUpdates(provider, updateSeconds*ONE_SECOND, 10, locationListener);
Log.d(getClass().getName(), String.format("Request location from %s provider, every %d sec.", provider, updateSeconds));
} else
Log.d(getClass().getName(), "Location request running");
}
public void StopFinder() {
locationManager.removeUpdates(locationListener);
isLooking = false;
}
public boolean IsLocating() {
return isLooking;
}
}
My problem is that the onLocationChanged routine is not called, even though I know there are new readings. For example, when configured to read in Passive Mode, I run Waze and see myself moving. Is it possible that the call to onLocationChanged being blocked by the semaphore? If so, how do I get around this? I want to be able to change the parameters for requestLocationUpdate dynamically.
I think getting a tumbleweed badge is a very dubious honor, but here is the answer:
Yes, the .acquire() call blocks the thread, and the onLocationChanged() method is not called.
The solution is to have a handler run a runnable, such as:
public void onLocationChanged(Location location) {
xxxService.locHandler.post(xxxService.locationRun);
}
where
Runnable locationRun = new Runnable() {
#Override
public void run() {
// handle stuff for new location
}
};
The general principle is that you send and handle events, rather than running a polling loop. If you need to handle a non-event, e.g. no new location read, then you set up a countdown timer.
When my map activity is called I make a call in the onCreate to addUserMapPoint. This function contains two instances where I try to get the location information using myOverlay.getMyLocation. On the initial load of this activity the result of the first attempt returns a null GeoPoint and after the main UI thread completes the second attempt located in the listener thread of myOverlay.runOnFirstFix(new Runnable()… is call after a second and does contain a GeoPoint that does contain a lat and lon. The call inside this listener function does appear to put the dot on the map and the line mapController.animateTo(gp) does move the map to my location. My app has a refresh button that when clicked fires off this activity again. I need the lat and lon in order to fetch location data from another service. After the refresh, the second time through the map activity code I was expecting the first call to myOverlay.getMyLocation() would now be able to get the GeoPoint, but it is still null.
If I’m not able to get the GeoPoint by this first call to myOverlay.getMyLocation then how can I pass the lat and lon value from the second call found in the myOverlay.runOnFirstFix(new Runnable()… thread. You will notice that I have been trying to add the lat and lon to MyApp which is helper bean class but the lat and lon in this class is null even after the refresh. If I manually set a lat and lon manually in the addUserMapPoint function the first time the activity is accessed these values are retained. I’m guessing that this is because it is being set on the main UI thread.
public class MapActivity extends com.google.android.maps.MapActivity {
private MapView mapView = null;
private MapController mapController = null;
private MyLocationOverlay myOverlay = null;
public static MyApp app;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
app = (MyApp) getApplicationContext();
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
mapController = mapView.getController();
List<Overlay> mapOverlays = mapView.getOverlays();
mapOverlays.clear();
addUserMapPoint(mapView);
if (!app.isLocServOff()) {
//map other points – service call to get items from our service near lat and lon
addOtherMapPoints(mapOverlays);
} else {
Toast.makeText(app.getApplicationContext(),"Current location could not be found.",Toast.LENGTH_LONG).show();
}
}
private void addUserMapPoint(MapView mapView){
myOverlay = new MyLocationOverlay(app.getApplicationContext(), mapView);
myOverlay.disableCompass();
myOverlay.enableMyLocation();
if(app.getMyLat()==null||app.getMyLon()==null){
GeoPoint gp = myOverlay.getMyLocation();
if(gp!=null){
app.setMyLat(Helper.latLon1E6Calc(gp.getLatitudeE6()));
app.setMyLon(Helper.latLon1E6Calc(gp.getLongitudeE6()));
app.setLocServOff(false);
}else{
app.setLocServOff(true);
}
}
myOverlay.runOnFirstFix(new Runnable() {
public void run() {
GeoPoint gp = myOverlay.getMyLocation();
if(gp!=null){
app.setMyLat(Helper.latLon1E6Calc(gp.getLatitudeE6()));
app.setMyLon(Helper.latLon1E6Calc(gp.getLongitudeE6()));
app.setLocServOff(false);
mapController.animateTo(gp);
}else{
app.setLocServOff(true);
}
}
});
mapView.getOverlays().add(myOverlay);
}
}
Your help is being requested for the following question.
How can I get a GeoPoint that contains a lat and lon in the main UI thread or how can I pass these values from GeoPoint I am able to get from the myOverlay.runOnFirstFix(new Runnable()… thread?
If you are going to suggest that I use Handler or runOnUiThread please provide code example that passes the lat and lon back to something that can be used by the main UI thread/map view. I have tried things like the following code that did not produce the desired outcome. I was able to get the toast message to show up, but was not able to get the lat and lon passed in a way I could use.
final Handler handler = new Handler();
myOverlay.runOnFirstFix(new Runnable() {
#Override public void run() {
handler.post(new Runnable() {
#Override public void run() {
GeoPoint gp = myOverlay.getMyLocation();
if(gp!=null){
app.setMyLat(Helper.latLon1E6Calc(gp.getLatitudeE6()));
app.setMyLon(Helper.latLon1E6Calc(gp.getLongitudeE6()));
app.setLocServOff(false);
mapController.animateTo(gp);
}else{
app.setLocServOff(true);
}
//Toast.makeText(getApplicationContext(),"wowoowowowoowoowowow",Toast.LENGTH_LONG).show();
}
});
}
});
I've also used code like the following to get the lat and lon and it works, but because the current location would sometimes be a different lat and lon than whas was being returned becuase for example I could not get a gps signal but yet an old value was returned. I added checks to see if the lat/lon data was older than 2 minutes, but I still could not match up the most recent lat and lon with that that is returned by myOverlay.getMyLocation.
LocationManager locMgr = (LocationManager)appcontext.getSystemService(Context.LOCATION_SERVICE);
MyLocationListener locLstnr = new MyLocationListener();
//fetch current location for current location
locMgr.requestSingleUpdate(LocationManager.GPS_PROVIDER, locLstnr, appcontext.getMainLooper());
Bellow you can find some examples on how to get the current location in the UI thread, but first of all, some background information.
GPS may take some time (15 seconds to 1 minute) to get the first fix after the request for new location is made. This is the reason you your first attempt to get it from myOverlay fails, and only after the first fix you can get the value.
During this blackout period you can use getLastKnownLocation() to get the last good known GPS location if you are in a hurry. If not availble it returns null
The code:
Last Known Location
LocationManager locMgr=(LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
Location loc = locMgr.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if(loc != null){
//we have a valid location. Check location date
}
Requesting a Single Location Update
LocationManager locMgr=(LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
locMgr.requestSingleUpdate(LocationManager.GPS_PROVIDER, locationListener, appcontext.getMainLooper);
Requesting a Continuous Location Update
LocationManager locMgr = (LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
//use 0 for minDistance and minDistance between updates if you need the maximum update frequency.
locMgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, minDistance, minTime, locationListener);
Location Listener for Single and Continuous position update
This is the last piece of code, and is the place where you get the new fresh locations requested above.
When a new location that match your request critirea defined above is retrieved by GPS, this listener is immediately called, unless you device is busy doing something else that can't be interrupted (i.e. callback is on a paused thread or that hit a lock).
From within the onLocationChanged() you can set any class level filed as appropriate. If you registered the listener from the UI thread, then this will be running running on the UI.
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location fix) {
fix.setTime(fix.getTime() + timeZoneOffset); //Add Timezone offset if needed
//here you have a fresh new location in fix...
//You can set the value of any class level field from here
}
public void onProviderDisabled(String provider) {
}
public void onProviderEnabled(String provider) {
}
public void onStatusChanged(String provider, int status, Bundle extras) {
}
};
Regards.
handler.post(new Runnable() {
#Override public void run() {
GeoPoint gp = myOverlay.getMyLocation();
if(gp!=null){
app.setMyLat(Helper.latLon1E6Calc(gp.getLatitudeE6()));
app.setMyLon(Helper.latLon1E6Calc(gp.getLongitudeE6()));
app.setLocServOff(false);
// HERE WE HAVE VALID gp VALUE AND WE NEED TO SHARE IT
mapController.animateTo(gp);
}else{
app.setLocServOff(true);
}
}
});
I think that your app.set/get|MyLat/Lon not working because you call them from different threads. To fix it synchronize set and get methods for MyLat/Long. (create Object for synchronization and sync on it)
Or if you like your way with handler this should work:
final Handler handler = new Handler(); // BE SURE TO RUN THIS LINE ON UI THREAD
...
myOverlay.runOnFirstFix(new Runnable() {
#Override public void run() {
// THIS PART WORKS AS BEFORE
final GeoPoint gp = myOverlay.getMyLocation();
mapController.animateTo(gp);
...
// AND THIS RUNNABLE TO UPDATE MyLat/MyLong FROM UI THREAD
handler.post(new Runnable() {
#Override public void run() {
app.setMyLat(Helper.latLon1E6Calc(gp.getLatitudeE6()));
app.setMyLon(Helper.latLon1E6Calc(gp.getLongitudeE6()));
});
}
});
Some of the most important points you must take into account while seeking Device's location are:
Satellite GPS fix is not guaranteed to be received in adequate amount of time. E.g. the device is inside a building / not under open sky.
Make sure the satellite GPS listeners are not kept active for long. Keeping the listener ON will imply keeping the GPS radio on all the time making it the biggest battery drain reason.
In the below code example, the poll method in LinkedBlockingQueue doesn't return until either a specified time interval is over or a Location is queued in.
Use something like the below to get the current Location:
Location getCurrentLocation() {
long startmillis = 0;
LinkedBlockingQueue<Location> mQueue = new LinkedBlockingQueue<Location>();
try{
long millisSinceLastCollection = System.currentTimeMillis() - startmillis;
startmillis = System.currentTimeMillis();
mQueue.clear();
// Register for Satellite GPS listener as well as Network GPS listener.
registerGPSListeners();
// Wait for a maximum of one minutes for a fix
Location firstfix = mQueue.poll(1, TimeUnit.MINUTES);
if(firstfix != null && firstfix.getProvider().equals(LocationManager.GPS_PROVIDER)) {
return firstfix;
}
long elapsedmillis = System.currentTimeMillis() - startmillis;
long remainingmillis = ONE_MINUTE_IN_MS - elapsedmillis;
if (remainingmillis <= 0){
return firstfix;
}
Location secondfix = mQueue.poll(remainingmillis, TimeUnit.MILLISECONDS);
if(secondfix != null && secondfix.getProvider().equals(LocationManager.GPS_PROVIDER)) {
return secondfix;
}
/*
* In case we receive fix only from Network provider, return it.
*/
if(firstfix != null && firstfix.getProvider().equals(LocationManager.NETWORK_PROVIDER)) {
return firstfix;
}
} catch(Exception e){
Logger.e("GPS: Exception while listening for the current location", e);
} finally {
Logger.i("GPS: Unsubscribing from any existing GPS listeners");
unregisterGPSListeners();
}
}
// GPS issue fix edit.
private void registerGPSListeners() {
LocationManager locationManager = (LocationManager)AirWatchApp.getAppContext().getSystemService(Context.LOCATION_SERVICE);
if(locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER))
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 30000, 100, oneShotNetworkGPSLocationListener, MyAppApp.getAppContext().getMainLooper());
if(locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 30000, 100, oneShotSatelliteGPSLocationListener, AirWatchApp.getAppContext().getMainLooper());
}
}
private void unregisterGPSListeners(){
final LocationManager locationManager = (LocationManager)MyApp.getAppContext().getSystemService(Context.LOCATION_SERVICE);
locationManager.removeUpdates(oneShotSatelliteGPSLocationListener);
locationManager.removeUpdates(oneShotNetworkGPSLocationListener);
}
//One shot location listener
protected LocationListener oneShotSatelliteGPSLocationListener = new LocationListener() {
public void onLocationChanged(Location location) {
try {
mQueue.put(location);
} catch (InterruptedException e) {
Logger.e("Exception in putting new Location to the queue", e);
}
Logger.d("GPS: Location received from Satellite GPS Provider");
unregisterGPSListeners();
}
public void onProviderDisabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
};
//One shot location listener
protected LocationListener oneShotNetworkGPSLocationListener = new LocationListener() {
public void onLocationChanged(Location location) {
try {
mQueue.put(location);
} catch (InterruptedException e) {
Logger.e("Exception in putting new Location to the queue", e);
}
Logger.d("GPS: Location received from Network GPS Provider");
// Stop Listener for one-shot location fix from Network GPS provider.
final LocationManager locationManager = (LocationManager)AirWatchApp.getAppContext().getSystemService(Context.LOCATION_SERVICE);
locationManager.removeUpdates(oneShotNetworkGPSLocationListener);
Logger.d("GPS: Unsubscribed the network location listener.");
}
public void onProviderDisabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
};
Android modifies the user interface and handles input events from one single user interface thread(main thread).
If the programmer does not use any concurrency constructs, all code of an Android application runs in this thread.
GPS is the best way to determine a user's location, but pinging a global positioning satellite too much will quickly drain a mobile device's battery, take long time to get user location and this method doesn't always work indoors. You are not getting your location in first attempt that's why you are getting null over there.
Android's Network Location Provider figures out a user's location based on cell tower and Wi-Fi signals. It not only uses less battery power than GPS, but it's also faster and it works whether the user is outside or inside.
I am giving my Working Code below that show progress dialog, listen for user's location & after getting location show user's location overlay on Google-map
I assume that you have give below permissions in your Menifest file
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.INTERNET"/>
My main class
public class MyLocationOnMap extends MapActivity {
private MapView mapView;
private MyLocationOverlay itemizedoverlay;
private LocationManager locationManager;
private String provider;
private MyLocationListener locationListener;
MyBroadCastreceiver myBroadCastreceiver;
/**
* My current Location <i>longitude</i>.
*/
static int longitude;
/**
* My current Location <i>latitude</i>.
*/
static int latitude;
/**
*My progress indicator.
*/
ProgressDialog loadingDialog;
public static final String INTENT_FILTER_TAG="my location broadcast receiver";
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_location_on_map);
loadingDialog = new ProgressDialog(this);
loadingDialog.setTitle("Hot Spots!");
loadingDialog.setMessage("Please wait ...");
loadingDialog.setIndeterminate(true);
loadingDialog.setCancelable(false);
loadingDialog.show();
// Configure the Map
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
mapView.setStreetView(true);
/**
* Get your location manager and Location Listener...
*/
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationListener=new MyLocationListener();
myBroadCastreceiver = new MyBroadCastreceiver();
if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
Log.i("GPS_Enabled", "GPS enable! listening for gps location.");
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 10000, 0, locationListener);
registerReceiver(myBroadCastreceiver, new IntentFilter(INTENT_FILTER_TAG));
} else if (locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
Log.i("Network_Enabled", "Network enable! listening for Network location.");
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 10000, 0, locationListener);
registerReceiver(myBroadCastreceiver, new IntentFilter(INTENT_FILTER_TAG));
} else {
loadingDialog.dismiss();
Toast.makeText(this, "No Provider enable!", Toast.LENGTH_LONG).show();
}
}//End of onCreate......
/**
* My BroadCast Receiver, that is called when i get the location of user.
* #author Rupesh Yadav.
*
*/
class MyBroadCastreceiver extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
//Remove location update when you get user`s location very first time.
locationManager.removeUpdates(locationListener);
//Remove the broadcast listener that update my location on map.
unregisterReceiver(myBroadCastreceiver);
GeoPoint point = new GeoPoint(latitude, longitude);
mapView.getController().animateTo(point);
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable drawable = MyLocationOnMap.this.getResources().getDrawable(R.drawable.hs_mapoverlay);
itemizedoverlay = new MyLocationOverlay(drawable, MyLocationOnMap.this);
OverlayItem overlayitem = new OverlayItem(point, "Hello!", "My Current Location :)");
itemizedoverlay.addOverlay(overlayitem);
mapOverlays.add(itemizedoverlay);
loadingDialog.dismiss();
}
}
/**
* My Location listener...
*/
class MyLocationListener implements LocationListener{
#Override
public void onLocationChanged(Location location) {
latitude=(int) ((location.getLatitude())*1E6);
longitude=(int) ((location.getLongitude())*1E6);
//Send broadcast to update my location.
Intent sendLocationIntent=new Intent(INTENT_FILTER_TAG);
sendBroadcast(sendLocationIntent);
}
#Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
#Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
}
#Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
}
MyLocationOverlay class
public class MyLocationOverlay extends ItemizedOverlay<OverlayItem> {
Context mContext;
private ArrayList<OverlayItem> hsOverlays = new ArrayList<OverlayItem>();
public MyLocationOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
// TODO Auto-generated constructor stub
}
public MyLocationOverlay(Drawable defaultMarker, Context context) {
super(boundCenterBottom(defaultMarker));
mContext = context;
}
#Override
protected OverlayItem createItem(int i) {
// TODO Auto-generated method stub
return hsOverlays.get(i);
}
#Override
public int size() {
// TODO Auto-generated method stub
return hsOverlays.size();
}
/**
* add new OverlayItem objects to map OverlayItem ArrayList.
*
* #param overlay
*/
public void addOverlay(OverlayItem overlay) {
hsOverlays.add(overlay);
populate();
}
/**
* Called when user clicks on map overlay.
*/
#Override
protected boolean onTap(int index) {
// TODO Auto-generated method stub
// return super.onTap(index);
OverlayItem item = hsOverlays.get(index);
AlertDialog.Builder dialog = new AlertDialog.Builder(mContext);
dialog.setTitle(item.getTitle());
dialog.setMessage(item.getSnippet());
dialog.show();
return true;
}
You can modify the Location Listener & Broadcasr Receiver according to your need.
I hope this will solve your problem.
Best regards!
I have used this class for detecting my lat & lon:
Hope this is useful for you too.
Example how to use:
GPSUtility.getInstance(Context).getLatitude();
GPSUtility.getInstance(CamPhotoModeAct.this).getLongitude()
public class GPSUtility {
public static final String TAG = "GPSUtility";
private Context ctx;
Timer timer1;
LocationManager lm;
LocationResult locationResult;
boolean gps_enabled=false;
boolean network_enabled=false;
private double latitude;
private double longitude;
private static SharedPreferences SHARED_PREF;
private static SharedPreferences.Editor EDITOR_SHARED_PREF;
private static GPSUtility this_instance;
public GPSUtility(Context ctx){
this.ctx = ctx;
SHARED_PREF = ctx.getSharedPreferences(ConstantsG.SHARED_PREF_FILE, Context.MODE_PRIVATE);
EDITOR_SHARED_PREF = SHARED_PREF.edit();
this.getLocation(innerLocationResult);
}
public static GPSUtility getInstance(Context ctx){
if(this_instance == null)
this_instance = new GPSUtility(ctx);
return this_instance;
}
public static void updateLocation(Context ctx){
GPSUtility.getInstance(ctx);//this writes the latitude and longitude in sharable preference file
}
public double getLatitude(){
String latitudeStr = SHARED_PREF.getString(ConstantsG.KEY_LATITUDE,null);
if(latitudeStr == null){
latitude = 0.0;
}
else{
latitude = Double.parseDouble(latitudeStr);
}
return latitude;
}
public double getLongitude(){
String longitudeStr = SHARED_PREF.getString(ConstantsG.KEY_LONGITUDE,null);
if(longitudeStr == null){
longitude = 0.0;
}
else{
longitude = Double.parseDouble(longitudeStr);
}
return longitude;
}
private void updateWithNewLocation(Location location) {
if (location != null) {
latitude = location.getLatitude();
EDITOR_SHARED_PREF.putString(ConstantsG.KEY_LATITUDE, String.valueOf(latitude) );
longitude = location.getLongitude();
EDITOR_SHARED_PREF.putString(ConstantsG.KEY_LONGITUDE, String.valueOf(longitude));
EDITOR_SHARED_PREF.commit();
}
}
public boolean getLocation(LocationResult result)
{
//I use LocationResult callback class to pass location value from GPSUtility to user code.
locationResult=result;
if(lm==null)
lm = (LocationManager) this.ctx.getSystemService(Context.LOCATION_SERVICE);
//exceptions will be thrown if provider is not permitted.
try {
gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch (Exception ex) {
Log.e(TAG, "Exception error: " + ex.getLocalizedMessage(), ex);
}
try {
network_enabled = lm
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
} catch (Exception ex) {
Log.e(TAG, "Exception error: " + ex.getLocalizedMessage(), ex);
}
//Toast.makeText(context, gps_enabled+" "+network_enabled, Toast.LENGTH_LONG).show();
//don't start listeners if no provider is enabled
if(!gps_enabled && !network_enabled){
Toast.makeText(this.ctx, "You should enable gps or be connected to network.", Toast.LENGTH_LONG).show();
return false;
}
if(gps_enabled)
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListenerGps);
if(network_enabled)
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListenerNetwork);
timer1=new Timer();
timer1.schedule(new GetLastLocation(), 10000);
return true;
}
LocationListener locationListenerGps = new LocationListener() {
public void onLocationChanged(Location location) {
timer1.cancel();
locationResult.gotLocation(location);
lm.removeUpdates(this);
lm.removeUpdates(locationListenerNetwork);
}
public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
};
LocationListener locationListenerNetwork = new LocationListener() {
public void onLocationChanged(Location location) {
timer1.cancel();
locationResult.gotLocation(location);
lm.removeUpdates(this);
lm.removeUpdates(locationListenerGps);
}
public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
};
class GetLastLocation extends TimerTask {
#Override
public void run() {
//Context context = getClass().getgetApplicationContext();
Location net_loc=null, gps_loc=null;
if(gps_enabled)
gps_loc=lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if(network_enabled)
net_loc=lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
//if there are both values use the latest one
if(gps_loc!=null && net_loc!=null){
if(gps_loc.getTime()>net_loc.getTime())
locationResult.gotLocation(gps_loc);
else
locationResult.gotLocation(net_loc);
return;
}
if(gps_loc!=null){
locationResult.gotLocation(gps_loc);
return;
}
if(net_loc!=null){
locationResult.gotLocation(net_loc);
return;
}
locationResult.gotLocation(null);
}
}
public static abstract class LocationResult{
public abstract void gotLocation(Location location);
}
LocationResult innerLocationResult = new LocationResult() {
#Override
public void gotLocation(Location location) {
updateWithNewLocation(location);
}
};
}
I read the tutorial about Obtaining User Location in Android Dev Guid and,
I try to adapt this to the following code.. but i don't know which location value I should put into isBetterLocation(Location location, Location currentBestLocation)
Example.class
private LocationManager locman;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
String context = Context.LOCATION_SERVICE;
locman = (LocationManager)getSystemService(context);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setPowerRequirement(Criteria.POWER_LOW);
String provider = locman.getBestProvider(criteria, true);
locman.requestLocationUpdates(
provider,MIN_TIME, MIN_DISTANCE, locationListener);
}
private LocationListener locationListener = new LocationListener(){
#Override
public void onLocationChanged(Location location) {
// What should i pass as first and second parameter in this method
if(isBetterLocation(location1,location2)){
// isBetterLocation = true > do updateLocation
updateLocation(location);
}
}
#Override
public void onProviderDisabled(String provider) {}
#Override
public void onProviderEnabled(String provider) {}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
};
protected boolean isBetterLocation(Location location, Location currentBestLocation) {
if (currentBestLocation == null) {
// A new location is always better than no location
return true;
}
//Brief ... See code in Android Dev Guid "Obtaining User Location"
}
Its not that hard really. What the code does is it receives continuous updates on locations found; you can have multiple listeners listening to different providers and as such those updates can be more or less accurate depending on the provider (GPS for example could be more accurate than network). isBetterLocation(...) evaluates if a location found by the listener is actually better than the one you already know about (and should have a reference to in your code). The isBetterLocation(...) code is well documented, so it shouldn't be hard to understand, but the first parameter location is the new location found by a provider, and currentBestLocation is the location you already know about.
The code I use is about the same as yours, except I don't just take best provider.
The handler stuff is because I don't want continued updates, just find the best possible location that is accurate enough for me within a maximum timeframe of two minutes (GPS can take a bit).
private Location currentBestLocation = null;
private ServiceLocationListener gpsLocationListener;
private ServiceLocationListener networkLocationListener;
private ServiceLocationListener passiveLocationListener;
private LocationManager locationManager;
private Handler handler = new Handler();
public void fetchLocation() {
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
try {
LocationProvider gpsProvider = locationManager.getProvider(LocationManager.GPS_PROVIDER);
LocationProvider networkProvider = locationManager.getProvider(LocationManager.NETWORK_PROVIDER);
LocationProvider passiveProvider = locationManager.getProvider(LocationManager.PASSIVE_PROVIDER);
//Figure out if we have a location somewhere that we can use as a current best location
if( gpsProvider != null ) {
Location lastKnownGPSLocation = locationManager.getLastKnownLocation(gpsProvider.getName());
if( isBetterLocation(lastKnownGPSLocation, currentBestLocation) )
currentBestLocation = lastKnownGPSLocation;
}
if( networkProvider != null ) {
Location lastKnownNetworkLocation = locationManager.getLastKnownLocation(networkProvider.getName());
if( isBetterLocation(lastKnownNetworkLocation, currentBestLocation) )
currentBestLocation = lastKnownNetworkLocation;
}
if( passiveProvider != null) {
Location lastKnownPassiveLocation = locationManager.getLastKnownLocation(passiveProvider.getName());
if( isBetterLocation(lastKnownPassiveLocation, currentBestLocation)) {
currentBestLocation = lastKnownPassiveLocation;
}
}
gpsLocationListener = new ServiceLocationListener();
networkLocationListener = new ServiceLocationListener();
passiveLocationListener = new ServiceLocationListener();
if(gpsProvider != null) {
locationManager.requestLocationUpdates(gpsProvider.getName(), 0l, 0.0f, gpsLocationListener);
}
if(networkProvider != null) {
locationManager.requestLocationUpdates(networkProvider.getName(), 0l, 0.0f, networkLocationListener);
}
if(passiveProvider != null) {
locationManager.requestLocationUpdates(passiveProvider.getName(), 0l, 0.0f, passiveLocationListener);
}
if(gpsProvider != null || networkProvider != null || passiveProvider != null) {
handler.postDelayed(timerRunnable, 2 * 60 * 1000);
} else {
handler.post(timerRunnable);
}
} catch (SecurityException se) {
finish();
}
}
private class ServiceLocationListener implements android.location.LocationListener {
#Override
public void onLocationChanged(Location newLocation) {
synchronized ( this ) {
if(isBetterLocation(newLocation, currentBestLocation)) {
currentBestLocation = newLocation;
if(currentBestLocation.hasAccuracy() && currentBestLocation.getAccuracy() <= 100) {
finish();
}
}
}
}
#Override
public void onStatusChanged(String s, int i, Bundle bundle) {}
#Override
public void onProviderEnabled(String s) {}
#Override
public void onProviderDisabled(String s) {}
}
private synchronized void finish() {
handler.removeCallbacks(timerRunnable);
handler.post(timerRunnable);
}
/** 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) {
//etc
}
private Runnable timerRunnable = new Runnable() {
#Override
public void run() {
Intent intent = new Intent(LocationService.this.getPackageName() + ".action.LOCATION_FOUND");
if(currentBestLocation != null) {
intent.putExtra(LocationManager.KEY_LOCATION_CHANGED, currentBestLocation);
locationManager.removeUpdates(gpsLocationListener);
locationManager.removeUpdates(networkLocationListener);
locationManager.removeUpdates(passiveLocationListener);
}
}
};
I want to implement whenever I launch my android
application,that time I want to start gps,
Whenever I close
application, I want to stop gps in device. How to implement
this concept in my application ?
The most important thing is to remove the LocationListener in all onPause methods of your Activities. You then can restart the listening in your onResume methods.
If you don't remove the listener in the onPause method the GPS will be active even if your app is the paused in the background. See the activity lifecycle for more information.
John, you need to use the LocationManager class. Here is a tutorial on how to get the users location.
First add bellow Class and interface to your application.
public class GPSManager
{
private static final int gpsMinTime = 500;
private static final int gpsMinDistance = 0;
private LocationManager locationManager = null;
private LocationListener locationListener = null;
private GPSCallback gpsCallback = null;
public GPSManager()
{
locationListener = new LocationListener()
{
public void onProviderDisabled(final String provider)
{
}
public void onProviderEnabled(final String provider)
{
}
public void onStatusChanged(final String provider, final int status, final Bundle extras)
{
}
public void onLocationChanged(final Location location)
{
if (location != null && gpsCallback != null)
{
Log.e("if location "+location,"if gpscallback"+gpsCallback);
gpsCallback.onGPSUpdate(location);
}
else{
Log.e("else location "+location,"else gpscallback"+gpsCallback);
}
}
};
}
public void startListening(final Activity activity)
{
if (locationManager == null)
{
locationManager = (LocationManager) activity.getSystemService(Context.LOCATION_SERVICE);
}
final Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
final String bestProvider = locationManager.getBestProvider(criteria, true);
if (bestProvider != null && bestProvider.length() > 0)
{
locationManager.requestLocationUpdates(bestProvider, GPSManager.gpsMinTime,
GPSManager.gpsMinDistance, locationListener);
}
else
{
final List<String> providers = locationManager.getProviders(true);
for (final String provider : providers)
{
locationManager.requestLocationUpdates(provider, GPSManager.gpsMinTime,
GPSManager.gpsMinDistance, locationListener);
}
}
}
public void stopListening()
{
try
{
if (locationManager != null && locationListener != null)
{
locationManager.removeUpdates(locationListener);
}
locationManager = null;
}
catch (final Exception ex)
{
}
}
public void setGPSCallback(final GPSCallback gpsCallback)
{
this.gpsCallback = gpsCallback;
}
public GPSCallback getGPSCallback()
{
return gpsCallback;
}
}
Interface:
public interface GPSCallback
{
public abstract void onGPSUpdate(Location location);
}
then implement this interface in your activity and also add below code in your activity
gpsmanager=new GPSManager();
gpsmanager.startListening(YourActicvityname.this);
gpsmanager.setGPSCallback(this);
To stop GPS call gpsmanager.stopListening() at where you want to close the application