I am developing a proximity alert related project. For that whenever I opened my app, I need to get exact readings of where I am. Even though I am following the right coding practices prescribed by android documentation, I am not getting the expected result.
Why there is no alternative command in entire android Geolocation coding for getLastKnownLocation which will give us where we are earlier not now.
I have did one javascript coding in the same lines. There My code is working properly. The Descriptive address and coordinates where my device is working nice there. Those commands getCurrentPosition and watchPosition are givinga beautiful response via their event handler callbacks. Why there is no getCurrentLocation in android geolocation parlance?
Even though I have followed relevant coding practices, MyLocationListener myLocationUpdate which implements LocationListener is not updating my new location when I am moving from one place to another place. I gave MINIMUM_DISTANCE_CHANGE_FOR_UPDATES as 1(in meters) and MINIMUM_TIME_BETWEEN_UPDATES as 1000 (in milliseconds).
I am giving important code snippets below to understand the problem
in onCreate handler of the activity
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
boolean enabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
if (!enabled) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
myLocationUpdate = new MyLocationListener();
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,MINIMUM_TIME_BETWEEN_UPDATES,MINIMUM_DISTANCE_CHANGE_FOR_UPDATES, myLocationUpdate);
retrieveLocationButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(MainActivity.this,"Finding Location",Toast.LENGTH_LONG).show();
showCurrentLocation();
}
});
latituteField = (TextView) findViewById(R.id.display_Location);
showCurrentLocation();
in showCurrentLocation function
I am using locationManager.getLastKnownLocation(provider) to retrieving that location.
By using GeoCoder Object and the command geocoder.getFromLocation(latitude, longitude, 1) to get First Address match for the coordinates.
// internal class to handle location cahnge event
private class MyLocationListener implements LocationListener contains all the Overridden functions including public void onLocationChanged(Location location)
But Practically I am getting nothing out of all the application. I have already recorded Time via location.getTime(). It is showing a fixed earlier time, but not the interval i specified.
the problem with getting GPS location is that it isnt available immediately. From my understanding of GPS location provider is that when you request location update, the gpr provider will try to connect to the gps satellites which runs in a separate thread (not entirely sure about it). In the meantime your program is executed normally and there maybe a chance that you wont get any location.
What you can do is use Fused Location Provide which was introduced in this year's IO Event. You can find the tutorial here
Related
j know that since 4.0 it s impossible to trigger programmatically gps
but besides that there are three possibilities to localise
1) gps and wifi and mobile network (all together)
2) only wifi and mobile network
3) only gps
is there some possible code to get through the second one
so let's be clear j don't want to trigger wifi. that i know
j want to trigger localisation by whatever wifi (and)or mobile network without using gps
j tried to implement some object like skyhook' WPSPeriodicLocationCallback or WPSLocationCallback but
it doesn 't work without triggering the official android security menu
so what j want is getting through the positionning system only with wifi or internet connection and that by code
avast antitheft does that giving back some information with more or less accuracy .
i would like to reproduce the same
thanks in advance
You can get locating the position using the LocationManager.NETWORK_PROVIDER instead of LocationManager.GPS_PROVIDER. The NETWORK_PROVIDER will resolve on the GSM or wifi, which ever available. Obviously with wifi off, GSM will be used. Keep in mind that using the cell network is accurate to basically 500m.
http://developer.android.com/guide/topics/location/obtaining-user-location.html has some really great information and sample code.
After you get done with most of the code in OnCreate(), add this:
// Acquire a reference to the system Location Manager
LocationManager locationManager = (LocationManager)this.getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
// Called when a new location is found by the network location provider.
makeUseOfNewLocation(location);
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
You could also have your activity implement the LocationListener class and thus implement onLocationChanged() in your activity or you can use this tutorial to get lat and lang.
Copypasted from this answer.
My app is working in Ice Cream Sandwich perfectly well, but now I tried it on KitKat and faced some problems.
The app is kind of server I'm running in my old phone and it provides location when requested. In ICS when the location is requested the GPS icon starts blinking and soon the app receives location update and sends it forward. But now with KitKat the GPS icon does not start blinking when location is requested. The app gives 60s time for finding the GPS location, but usually the GPS isn't even activated during this time. Still now and then the GPS suddenly activates itself (during the 60s) and the location is provided to my app.
Why the GPS doesn't get activated even my app requests location? As said, my app works with ICS without problems. And I do have required permissions set in my manifest.
public variables:
public static LocationManager mlocManager = null;
public static LocationListener mlocListener_fast = null;
onCreate:
mlocListener_fast = new MyLocationListener();
mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Handling user requested command (location request)
mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener_fast);
What should I do differently to get the GPS location instantly without waiting for sudden location updates/GPS activation, probably triggered by Android or some other app?? Unfortunately I don't have any other Android device I could try this.
EDIT:
It seems that if the app does not request location at startup, then the location request works every time when requested time after time. But if the location was requested (and received) on startup, then the location request does not work anymore. What can cause that? I use exactly the same line (the same location mgr and the same location listener) for location request on startup and later if requested.
Even if the location listener used in startup is different than the one used later, the location request does not work anymore. Tried even initialize the location mngr again just before requesting the location again and it did not help. What's with this??
EDIT2:
It just seems that with KitKat it's not possible to request multiple location requests. I used to have several location listeners for different purposes. For example one for updating location once per hour and another for getting location instantly (user requested update). Now it seems that if I have the 1/60min location listener running as normal, then KitKat location manager fails to handle the instant location requests. Have anyone faced this issue? Would be good to know which Android versions have this issue.
Workaround for this issue is to use only one LocationManager and one LocationListener. If your app has needs for different kind of simultaneous location requests (with different parameters), then you need to implement a "location request handler" which decides which parameters should be used for the location request i.e. which parameters have the tightest requirements for location.
Here is a simple example code that explains the idea of "location request handler":
class LR {
long lock_min_time; // defined in set_lock_lr before using
float lock_min_dist;
boolean lock_active = false;
long idle_min_time = 3600000; // 1 per hour
float idle_min_dist = 200;
boolean idle_active = true;
long fast_min_time = 0;
float fast_min_dist = 0;
boolean fast_active = false;
//constructor
public LR()
{}
public void set_lock_lr(long min_time, float min_dist, boolean active)
{
lock_active = active;
lock_min_dist = min_dist;
lock_min_time = min_time;
System.out.println("LR lock set: "+min_time+", "+min_dist+", "+active);
update_location_request();
}
public void set_idle_lr(boolean active)
{
idle_active = active;
System.out.println("LR idle set: "+active);
update_location_request();
}
public void set_fast_lr(boolean active)
{
fast_active = active;
System.out.println("LR fast set: "+active);
update_location_request();
}
private void update_location_request()
{
// Remove current location request
mlocManager_basic.removeUpdates(mlocListener_basic);
if(fast_active)
{
mlocManager_basic.requestLocationUpdates(LocationManager.GPS_PROVIDER, fast_min_time, fast_min_dist, mlocListener_basic);
System.out.println("LR: fast_active");
}
else if(lock_active)
{
mlocManager_basic.requestLocationUpdates(LocationManager.GPS_PROVIDER, lock_min_time, lock_min_dist, mlocListener_basic);
System.out.println("LR: lock_active");
}
else if(idle_active) // only idle updates
{
mlocManager_basic.requestLocationUpdates(LocationManager.GPS_PROVIDER, idle_min_time, idle_min_dist, mlocListener_basic);
System.out.println("LR: idle_active");
}
}
}
In my app, I need to get the location of my users. Since my app is going to do it constantly, I want to change the location provider in certain conditions (between GPS and NETWORK providers). My app is going to detect such conditions and change it.
But, I'm not sure how to change it dynamically.
So far, I have a thread (that, among other things, will check for these conditions) and I want it to change the location provider too. My code until now is as below:
public void run() {
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
LocationListener locationController = new LocationController();
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, time, desltaDistance, locationController );
while (serviceIsRunning) {
...
if (conditionsAreMet) {
locationManager.removeUpdates(locationController);
if (provider == LocationManager.GPS_PROVIDER)
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, time, desltaDistance, locationController );
else
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, time, deltaDistance, locationController );
}
...
}
}
*The LocationController class implements LocationListener.
But, it don't seems to be the better way to do it. So, what I want to know is: there is a better way to change the location provider automatically?
Since no one answered this question, here is how I figured it out.
Instead of make the change between the providers, I registered a constant controller for the NETWORK_PROVIDER. And, according to my conditions, a controller for the GPS_PROVIDER may be registered or not.
It's easier to register/unregister the locations request for one provider, instead of keep changing between them.
I'm trying to get the user's location within Android, the code below works however it always returns the same location no matter what I do. I've tested out in the middle of an empty parking lot to ensure the GPS is locked on, and it is. Google maps also shows my location correctly. Is there something wrong with the code below?
public class LocationTestActivity extends Activity implements LocationListener
{
private Location myLoc;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
output = (TextView) findViewById(R.id.output);
myLong = (TextView) findViewById(R.id.longi);
myLat = (TextView) findViewById(R.id.lat);
myRefreshed = (TextView) findViewById(R.id.counter);
mgr = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
}
#Override
public void onLocationChanged(Location location)
{
timesChanged++;
myRefreshed.setText("Refreshed: " + timesChanged);
myLong.setText("Longitude: " + location.getLongitude());
myLat.setText("Latitude: " + location.getLatitude());
}
}
I'd like to add that I can pass in a location using the emulator with no problem. I also removed the other needed methods required by LocationListener for clarity. Thanks for the help!
First make sure that onLocationChanged() is actually getting called. If your GPS has locked before then there is a chance that onLocationChanged won't get fired at all because the phone thinks that you haven't really moved. Therefore it is not a good practice to rely only on requestLocationUpdates() to get your current location.
In general here is what you should do to get your position:
You should use getLastKnownLocation() first to try locating your current location based on last known position.
Check if the location retrieved from step #1 is within reasonable time (not too old) by calling getTime() in the location and comparing with the current time
If this last known position is considered old (I normally use 5-10 minutes depending on the context of the app) then you start requestLocationUpdates() with specific distance (the app should make assumption that the user has moved within the specified limit of last known position)
Implement the onLocationChanged() as desired
Another note, I notice you are only using GPS, there is a lot of situation where GPS cannot lock and therefore never call onLocationChange(), your code should take account of that and checking Network based triangulation in the case onLocationChange() is not called within specified time
Try getting last location fix
Location loc = mgr.getLastKnownLocation(LocationManager.GPS_PROVIDER);
and give some time/distance between each location service request
mgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, this);
And I hope you have enough patience to wait until your device retrieves the location and onLocationChanged() is triggered ;) Joking.
please check your manifest file whether have you added those permission or not.
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"></uses-permission>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"></uses-permission>
One more thing.Where did you call "removeUpdates()"?
So I'm trying to sample the gps coordinates just once in an application. I don't want to create a LocationListener object to constantly get gps updates. I want to wait until receiving the coordinates, and then proceed on to another task.
Here is a code snippet
LocationManager lm = (LocationManager)act.getSystemService(Context.LOCATION_SERVICE);
Criteria crit = new Criteria();
crit.setAccuracy(Criteria.ACCURACY_FINE);
String provider = lm.getBestProvider(crit, true);
Location loc = lm.getLastKnownLocation(provider);
The loc variable is always null in the emulator. I tried using the command "geo fix latitude longitude" to set it, and also I tried using the DDMS way of setting it. Neither method had any effect on the code. Also the snippet isn't causing any exceptions.
Thanks for your help.
The call to request update for a location is not blocking, hence it wont wait there. Also the provider in emulator may not have been started.
A possible check could be to see if the settings in it disable gps provider ? then send geo fix.
However, I would use Location Listener, it would be ideal in your case since you need a geo fix to proceed further.Location Listener is Used for receiving notifications from the LocationManager when the location has changed. You can unregister the listener after first geofix.
Note: It can take some time on device to get current location, and even on device this can return null.
Try using the MyLocationOverlay , create a runnable that does what you need to do with that GPS location, and pass it to
boolean runOnFirstFix(java.lang.Runnable runnable)
Queues a runnable to be executed as soon as we have a location fix.
and then disable the location updates for the MyLocationOverlay.
Edit: The reason the location is null is because at the time that code is run, no geofix has been received.