The Location object has a getTime() method that should supply you with the
age of the fix. The getLastKnownLocation() call does not miraculously have
another source of location information than what you would get with the
upcall. Set the time in requestLocationUpdates to 0 to get notifications as
frequently as possible: that way you have the most up-to-date location your
device can give you.
Ludwig
2009/2/4 Anna PS <annapowellsm...@googlemail.com>
>
> Hi Ludwig,
>
> Thanks for the suggestion. I do implement a listener, when the
> application opens. But I found that the GPS data using
> getLastKnownLocation was often out of date or inaccurate, and that
> caused me real problems, since it's a mapping application and the data
> needs to be very accurate - I need to warn the user if it isn't. Hence
> the polling to make sure it's up to date. (I run the polling in a
> background thread.)
>
> I've pasted my listener code below, that I call from onCreate... do
> you suggest any changes?
>
> thanks,
> Anna
>
> //This function called from onCreate...
> public boolean testProviders() {
> Log.d(LOG_TAG, "testProviders");
> String location_context = Context.LOCATION_SERVICE;
> locationmanager = (LocationManager) getSystemService
> (location_context);
> listener = new LocationListener() {
> public void onLocationChanged(Location location) {
> }
>
> public void onProviderDisabled(String provider) {
> }
>
> public void onProviderEnabled(String provider) {
> }
>
> public void onStatusChanged(String provider, int
> status,
> Bundle extras) {
> }
> };
>
> locationmanager.requestLocationUpdates("gps", 500, 0,
> listener);
>
> Log.d(LOG_TAG, "Checking location with provider " + "gps");
>
> location = locationmanager.getLastKnownLocation("gps");
>
> if (location != null) {
> latitude = location.getLatitude();
> longitude = location.getLongitude();
> latString = latitude.toString();
> longString = longitude.toString();
> Log.d(LOG_TAG, "Location found: latitude" +
> latString
> + " and longitude " + longString);
> return true;
>
> } else {
> Log.d(LOG_TAG, "Location not found");
> return false;
> }
>
>
> On 2 Feb, 12:50, Ludwig <ludwigbrinckm...@gmail.com> wrote:
> > I suggest you better implement a location listener, which is much more
> > light-weight than the busy polling you are implementing. You can cancel
> your
> > subscription to location updates once you have one that satisfies
> you.Ludwig
> >
> > 2009/2/1 Anna PS <annapowellsm...@googlemail.com>
> >
> >
> >
> > > Great - thank you. I'll remember to read the documentation next
> > > time :)
> >
> > > I've pasted my code below in case anyone wants to borrow it: it keeps
> > > polling for up-to-date and accurate GPS data, up to a maximum of 10
> > > seconds. If by then the GPS data is old or not accurate enough, it
> > > just returns false.
> >
> > > The code feels a bit dubious, but it seems to do the job.
> >
> > > Anna
> >
> > > long locationTime = location.getTime();
> > > long currentTime = System.currentTimeMillis();
> > > timeDifference = (currentTime - locationTime) /
> > > 1000;
> >
> > > float accuracy = location.getAccuracy();
> > > int count = 0;
> >
> > > // Wait for accurate GPS data, up to a maximum
> of 10
> > > seconds before
> > > // throwing an error
> > > while (((timeDifference > 10) || (accuracy >
> 20.0))
> > > && (count <
> > > 20)) {
> > > location =
> > > locationmanager.getLastKnownLocation("gps");
> > > locationTime = location.getTime();
> > > currentTime =
> System.currentTimeMillis();
> > > timeDifference = (currentTime -
> > > locationTime) / 1000;
> > > accuracy = location.getAccuracy();
> > > Log.d(LOG_TAG, "getting up to date GPS
> data,
> > > time diff = "
> > > + timeDifference + " &
> > > accuracy = " + accuracy
> > > + " & count = " +
> count);
> > > try {
> > > Thread.currentThread();
> > > Thread.sleep(500);
> > > } catch (InterruptedException ie) {
> > > }
> > > count++;
> > > }
> > > // No accurate GPS data? Exit here and warn the
> user
> > > if ((timeDifference > 10) || (accuracy > 20.0))
> {
> > > return false;
> > > }
> >
> > > On 27 Jan, 03:38, gjs <garyjamessi...@gmail.com> wrote:
> > > > Hi,
> >
> > > > Subtract the Location.getTime() value from the current time to get
> the
> > > > age of the last fix.
> >
> > > > Seehttp://
> > > code.google.com/android/reference/android/location/Location.html
> >
> > > > Regards
> >
> > > > On Jan 23, 10:07 am, Anna PS <annapowellsm...@googlemail.com> wrote:
> >
> > > > > Hi
> >
> > > > > When you get GPS location using getLastKnownLocation, is there a
> way
> > > > > to check how old the data is, i.e. when the location was last
> > > > > updated?
> >
> > > > > I'm noticing that sometimes my app is giving me an out-of-date
> > > > > location (usually because the sky is not visible when the app
> starts)
> > > > > - it'd be good to warn the user about this.
> >
> > > > > It's possible to check the age of the data on the iPhone I believe,
> is
> > > > > it possible in Android?
> >
> > > > > thanks!
> > > > > Anna
> >
>
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