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In the LegacyLastLocationFinder.getLastBestLocation() method, the tests on the 
fix time are inverted!

if ((time < minTime && accuracy < bestAccuracy))
should be:
if ((time > minTime && accuracy < bestAccuracy))

if (time > minTime && bestAccuracy == Float.MAX_VALUE && time < bestTime)
should be:
if (time < minTime && bestAccuracy == Float.MAX_VALUE && time > bestTime)

and
if (locationListener != null && (bestTime > minTime || bestAccuracy > 
minDistance))
should be:
if (locationListener != null && (bestTime < minTime || bestAccuracy > 
minDistance))

It is less important but the comment for the minTime is misleading.

I also think the test to get the latest fix no matter its accuracy in both 
LegacyLastLocationFinder and GingerbreadLastLocationFinder should not include a 
check on minTime. Then,
if (time < minTime && bestAccuracy == Float.MAX_VALUE && time > bestTime)
should actually be:
if (bestAccuracy == Float.MAX_VALUE && time > bestTime)

Hi,

I am trying to use this code under Froyo but not able to do so, is there any 
specific requirement ? Can it only run on GB or Honeycomb ?

Regards
Girish

What steps will reproduce the problem?
1. hello everyone can u plz help my problem..actually there is no error in the 
project ...but at run-time it says the application has stopped 
unexpectedly..Please try again
2. if i upload the same project from my friend laptop to my android device i l 
get the main screen which contain 1 button i.e checkin to..
but nothing happens and main screen remains as it is.
3. plz any1 help me out.


What version of the product are you using? On what operating system?
Google api 3.0...windows 7

Please provide any additional information below.

PendingIntent locationListenerPassivePendingIntent = 
PendingIntent.getActivity(context, 0, passiveIntent, 
PendingIntent.FLAG_UPDATE_CURRENT);

should instead read

PendingIntent locationListenerPassivePendingIntent = 
PendingIntent.getBroadcast(context, 0, passiveIntent, 
PendingIntent.FLAG_UPDATE_CURRENT);

as you will discover if you copy this part of the code - the 
PassiveLocationChangedReceiver's onReceive is never called :-)

1. in PlacesUpdateService and PassiveLocationChangedReceiver, the type for 
latitude/longitude values stored in SharedPreferences is long. This causes the 
stored values to be clipped losing the decimals.

=> Needs conversion to float, or to be multiplied by 1E6 (microdegrees): 
save in SharedPreferences with prefs.putInt(lat * 1E6)
use with loc.setLatitude(prefsLat / 1E6)
this would be more consistant with GeoPoint's getLatitudeE6() and 
getLongitudeE6() 

2. Compared to this (great!) tutorial, I actually implemented 
SP_KEY_FOLLOW_LOCATION_CHANGES into a Preferences activity. When set to false, 
it creates an
IllegalArgumentException: Receiver not registered 
in disableLocationUpdates() when calling 
unregisterReceiver(locProviderDisabledReceiver)

=> Needs verification or try/catch.

Thanks for this very helpful tutorial. I have also implemented many of the 
issues reported here...

Hi,

great stuff an I'm using it in my current project. I found that under some 
conditions (getLastBestLocation has asked for an update and has registered a 
broadcast reciever but not received an update before I call cancel()) this one 
can appear: 

07-12 13:54:00.388: ERROR/ActivityThread(496): Service 
com.eventorama.mobi.lib.service.GetLocationService has leaked IntentReceiver 
com.eventorama.mobi.lib.location.GingerBreadLocationFinder$1@405f5d40 that was 
originally registered here. Are you missing a call to unregisterReceiver()?

I changed the cancel() method for example of the GingerBreadLocationFinder to:

public void cancel() {
    locationManager.removeUpdates(singleUpatePI);
    context.unregisterReceiver(singleUpdateReceiver);
 }

which fixes the issue. 

Keep the good examples going it's really a valuable resource!

I found the implemention in these two files is different, but I can't 
understand why. 
I think the LegacyLastLocationFinder's implemention is not correct, But the 
GingerbreadLastLocationFinder's implemention is correct.
Thanks for your sharing of this project, It helps me a lot

    // If the best result is beyond the allowed time limit, or the accuracy of the
    // best result is wider than the acceptable maximum distance, request a single update.
    // This check simply implements the same conditions we set when requesting regular
    // location updates every [minTime] and [minDistance]. 
    if (locationListener != null && (bestTime < minTime || bestAccuracy > minDistance)) { 
      IntentFilter locIntentFilter = new IntentFilter(SINGLE_LOCATION_UPDATE_ACTION);
      context.registerReceiver(singleUpdateReceiver, locIntentFilter);      
      locationManager.requestSingleUpdate(criteria, singleUpatePI);
    }

90% requestSingleUpdate ,when system get location will will send intent to 
BroadcastReceiver singleUpdateReceiver 

Sometime I see requestSingleUpdate not work.It make my application can not get 
location.But I test GooglePlace ,it can get location


What version of the product I'm using 4.1 

I 'm not understand why GooglePlace can get very good location

The FroyoLocationUpdateRequester does not contain an implementation for the 
requestLocationUpdates() method defined in the abstract base class 
LocationUpdateRequester.

Suggested fix:  pull the implementation for requestLocationUpdates() up from 
the child class "GingerbreadLocationUpdateRequester".

Additional suggestion:  Add a "removeUpdates(PendingIntent p)" to the class 
hierarchy, so that the requester (code that actually holds the PendingIntent) 
can signal to the location manager that it's no longer interested in location 
updates.  See attached files for implementation.  Implement similar for 
LegacyLocationUpdateRequester.

I found that both Passive and Active updates were being done when the app was 
in the foreground. I had changed the accuracy to COARSE

My solution was to disable the updates for the passive listener in onCreate() 
and only enable in onPause() when not exiting the app:

in onCreate
        Intent passiveIntent = new Intent(this, PassiveLocationChangedReceiver.class);
        locationListenerPassivePendingIntent = PendingIntent.getBroadcast(this, 0, passiveIntent, PendingIntent.FLAG_UPDATE_CURRENT);
        locationManager.removeUpdates(locationListenerPassivePendingIntent);

in disableLocationUpdates
        if (AppConstants.DISABLE_PASSIVE_LOCATION_WHEN_USER_EXIT && isFinishing())
            locationManager.removeUpdates(locationListenerPassivePendingIntent);
        else
            locationUpdateRequester.requestPassiveLocationUpdates(AppConstants.PASSIVE_MAX_TIME, AppConstants.PASSIVE_MAX_DISTANCE, locationListenerPassivePendingIntent);

Great article and excellent code. Thanks for this!

What steps will reproduce the problem?
1. start the app
2. rotate the between landscape and portrait
3. check logcat

Expected:
- no logcat messages about leaks

Actual:

- leak indicated in logcat:
E/ActivityThread( 8110): Activity 
com.radioactiveyak.location_best_practices.UI.PlaceActivity has leaked 
IntentReceiver 
com.radioactiveyak.location_best_practices.utils.GingerbreadLastLocationFinder$1
@419b1f00 that was originally registered here. Are you missing a call to 
unregisterReceiver()?

App built from source 2012-0 with Android 3.2 API, running on 4.0.4 (Samsung 
Galaxy Note).

Shouldn't the intent filter be for "android.intent.action.BATTERY_LOW" instead 
of "android.intent.action.ACTION_BATTERY_LOW"?

Intent.ACTION_BATTERY_LOW is the constant, but its value is 
android.intent.action.BATTERY_LOW.

"android.intent.action.ACTION_BATTERY_LOW" does not react to any intents on my 
phone, while "android.intent.action.BATTERY_LOW" does.

When I run the application under LG Optimus One in portrait mode, the "checkin" 
button does not show up (it is somewhere off-screen on the right). If I rotate 
the phone to landscape mode it shows up fine.

Normally this wouldn't be a big deal, but the first time I ran this application 
I thought it wasn't working. All I saw was a black screen asking me to check in 
but no obvious way to do so. It took me a couple of minutes to figure out that 
I had to rotate the phone.

Please move the checkin button under portrait mode so it fits in the screen. 
Alternatively (cheap hack) add some text asking the user to rotate the screen.

  Hi Reto,

Thanks for your example project !

It looks like the methode Criteria.setAccuracy does accept only:
Criteria.NO_REQUIREMENT = 0
Criteria.ACCURACY_FINE = 1
Criteria.ACCURACY_COARSE = 2

But in the 'GingerbreadLastLocationFinder' class, you use:
criteria.setAccuracy(Criteria.ACCURACY_LOW);

Criteria.ACCURACY_LOW = 1, the same than Criteria.ACCURACY_FINE !!!

It should be
criteria.setAccuracy(Criteria.ACCURACY_COARSE)

Even worst, setting criteria.setAccuracy(Criteria.ACCURACY_HIGH); throw an 
exception since Criteria.ACCURACY_HIGH (3) > Criteria.ACCURACY_COARSE (2)...

Maybe the Criteria constants should be set as enum or renamed, or something 
else to not be misused...

Thanks,
Seb.

Hello.

I am a new in android development.
Thank you for the article 
http://android-developers.blogspot.de/2011/06/deep-dive-into-location.html
I am not understand how to use PassiveLocationChangedReceiver.
I think that shoul be something like


PassiveLocationChangedReceiver lr = new PassiveLocationChangedReceiver();
IntentFilter ifilter = new IntentFilter(Intent. -=Some Intent Action=- );
var location = RegisterReceiver(lr, ifilter);

What Intent Action need to be used.
I am a Mono Android (Xamarin) developer.

Thank you.

FroyoSharedPreferenceSaver and GingerbreadSharedPreferenceSaver take in a 
"backup" parameter but ignore its value, backing up preferences no matter what 
happens.

Expected behavior: avoid backing up preferences if backup == false.

It looks like there are a couple of issues with the Eclair-specific code:

1) The booleans to enable/disable the services in the manifest file are 
reversed:

<service android:enabled="@bool/pre_froyo" 
android:name=".services.PlacesUpdateService"> and <service 
android:enabled="@bool/froyo_or_later" 
android:name=".services.EclairPlacesUpdateService">

should be

<service android:enabled="@bool/froyo_or_later" 
android:name=".services.PlacesUpdateService"> and <service 
android:enabled="@bool/pre_froyo" 
android:name=".services.EclairPlacesUpdateService">

2) Several classes do

PlacesConstants.SUPPORTS_ECLAIR ? EclairPlacesUpdateService.class : 
PlacesUpdateService.class

but should do 

PlacesConstants.SUPPORTS_FROYO ? PlacesUpdateService.class : 
EclairPlacesUpdateService.class

3) LegacyPlacesUpdateRequester is never instantiated in 
PlatformSpecificImplementationFactory.getLocationUpdateRequester()

// If there are still queued checkins then set a non-waking alarm to retry them.

Alarm time set in System.currentTimeMillis()  instead of 
SystemClock.elapsedRealtime()

1. The subtle differences in (the upper half of) getLastBestLocation() between 
GingerbreadLastLocationFinder and LegacyLastLocationFinder doesn't make sense 
to me. The code in GingerbreadLastLocationFinder looks correct.

2. The constructor GingerbreadLastLocationFinder() sets accuracy to 
ACCURACY_LOW but the comment above is about ACCURACY_COARSE (which is used in 
LegacyLastLocationFinder).

I suggest one of the following refactorings:
- Rename ILastLocationFinder to LastLocationFinder and turn it into an abstract 
class with common code, or
- Remove ILastLocationFinder, rename LegacyLastLocationFinder to 
LastLocationFinder, put the common code there and make 
GingerbreadLastLocationFinder extend that class.

While you're at it, you may also remove the redundant parenthesis in:
        if ((time > minTime && accuracy < bestAccuracy)) {

Oh, and thanks for an awesome deep dive! Helped me a lot.