I am doing a lot of job in onLocationChanged method, i want to lock the method until all jobs are done even if the location manager achieves it's condition.
for example i have the following code:
private LocationManager _locMgr;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
_locMgr = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
_locMgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 2, this);
}
public void onLocationChanged(Location location) {
//do alot of job
}
The problem i am facing that if the time in locationManager is greater than 2 seconds and greater than 2 meters it'll execute the onLocationChanged() even if there's tasks not finished.
Please somebody help me with this.
If you are sure that onLocationChanged() is called before finished, try this:
Declare an Activity field private bolean isAllDone = true;
Declare a lock object private final Object lock = new Object();
Then at onLocationChange test it:
public void onLocationChanged(Location location) {
if(isAllDone){
synchronized (lock){
if(isAllDone){
isAllDone = false;
//do alot of job
isAllDone = true;
}
}
}
}
Related
I have an AlarmManager that triggers every 30 minutes to an IntentService, and this intent service is to get the user's location each time. I have 2 ways of getting location: first it checks the getLastKnownLocation(), and if it was within the last 2 minutes it uses that, this part works perfectly.
The second way is if the last location was old or returns null, in which I want to get the new location once. For some reason this never calls onLocationChanged(). This results in my IntentService not returning coordinates much of the time, it only returns them if the getLastKnownLocation() was recent.
Here is my code for how it is set up, why is it that if I want to get a new location, it is never called? Check the comments in the code to see what is called and what is never called.
LocationListener locationListener;
LocationManager locationManager;
private final double MIN_COORD_DIFF = 0.0006;
public CoordinateAlarmReceiver(){
super("CoordinateAlarmReceiver");
}
#Override
protected void onHandleIntent(Intent intent) {
//THIS IS CALLED CORRECTLY
MyLog.i("coordinate alarm received");
locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Location lastLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
//if last location was in past 2 minutes, use that
if(lastLocation != null && lastLocation.getTime() > Calendar.getInstance().getTimeInMillis() - 2 * 60 * 1000) {
//THIS IS CALLED CORRECTLY
storeLocation(lastLocation);
MyLog.i("Last location was recent, using that");
}
else { //otherwise get new location
//THIS IS CALLED CORRECTLY
MyLog.i("Last location was old, getting new location");
locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
//THIS IS NEVER CALLED
MyLog.i("Got new coordinates");
storeLocation(location);
locationManager.removeUpdates(this);
}
#Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
#Override
public void onProviderEnabled(String s) {
}
#Override
public void onProviderDisabled(String s) {
}
};
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
}
}
You should use a Service instead of a IntentService. The IntentService finish when complete the task however, the service is running and can listen the location change events. Try to use a service.
Hope it helps you!!
...or most probably, I am doing it wrong. What I want is to display a Toast every one meter I walk inside home. The code below gives me wrong results, as the moment I install the app on my phone I get a Toast without even moving!
public class MainActivity extends Activity {
private LocationListener mLocationListener;
private String mLocationProvider;
private LocationManager mLocationManager;
private Location mCurrentLocation;
private int mCounter = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
mLocationListener = new MyLocationListener();
Criteria criterion = new Criteria();
criterion.setAccuracy(Criteria.ACCURACY_FINE);
criterion.setCostAllowed(true);
criterion.setPowerRequirement(Criteria.POWER_HIGH);
mLocationProvider = mLocationManager.getBestProvider(criterion, true);
}
#Override
protected void onResume() {
super.onResume();
mCurrentLocation = mLocationManager.getLastKnownLocation(mLocationProvider);
mLocationManager.requestLocationUpdates(mLocationProvider, 5000, 1, mLocationListener);
}
#Override
protected void onPause() {
super.onPause();
mLocationManager.removeUpdates(mLocationListener);
}
private class MyLocationListener implements LocationListener {
#Override
public void onLocationChanged(Location newlocation) {
float distance = mCurrentLocation.distanceTo(newlocation);
if (distance >= 1) {
mCounter++;
Toast.makeText(MainActivity.this, String.format("Message #%d: you walked one more meter", mCounter), Toast.LENGTH_SHORT).show();
mCurrentLocation = newlocation;
}
}
}
}
A GPS signal is not precise enough to give exact locations for a 1m radius. There can be deviation peeks up to 50 - 100m in real situations using GPS. This depends much on the environment you are at. GPS will be reflected by buildings, water etc. An average deviation is 10 - 20m. This will get even worse if your inside of a building using a GPS provider instead of a Network provider.
Furthermore you will never get the same coordinates twice in a row, because of this. Even if you don't move! To avoid that you could temporarly save the location and compare it with the new location. If the distance between them hits a defined boarder use the new location.
Change your location provider to GPS. And you have instantiated the LocationListener before you request the new Location(in onResume(); onResume() will be called after onCreate()). This might be the reason for your app showing Toast on start up.. Try to instantiate LocationListener after the requestLocationUpdates()..
I'm developing an application that needs to get location updates fast, doesn't matter the accuracy of them. I need to be able to get about one reading per second. How can I do this?
Other than specifying 0 for both the minimum distance and minimum time values in requestLocationUpdates(), you have no control over the rate. Android will give you all of the fixes it receives, but whether that is 30 fixes per second or 30 seconds per fix will depend upon hardware, environment (e.g., is the user indoors?), and so forth.
You could build a layer between the Android location updates and your receiver.
In your own layer, catch the Android location updates, and pass the same location 30 times per second to your receiver, until you get a new location.
EDIT
Something like this (not tested):
public class MyLocationManager implements LocationListener{
private List<MyLocationListener> listeners;
private Location lastLocation;
private Handler handler;
public MyLocationManager(){
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lastLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
listeners = new ArrayList<MyLocationListener>();
handler = new Handler();
sendLocationUpdates();
}
private void sendDelayedLocationUpdates(){
handler.postDelayed(locationUpdater, 200);
}
public void addMyLocationListener(MyLocationListener mListener){
listeners.add(mListener);
}
public void removeMyLocationListener(MyLocationListener mListener){
listeners.remove(mListener);
}
#Override
public void onLocationChanged(Location location) {
lastLocation = location;
}
public interface MyLocationListener{
public void onLocationChanged(Location location);
}
private Runnable locationUpdater = new Runnable(){
#Override
public void run(){
for(MyLocationListener mListener : listeners){
mListener.onLocationChanged(lastLocation);
}
sendDelayedLocationUpdates();
}
};
}
I have been working for 2 days looking for this bug. I have searched stackoverflow and Android documentation with no luck.
My onLocationChanged code has a counter in it that counts how many times it has been called and if I back arrow out of the activity screen on the phone and return, the counter will go up by 2 for each update. If I back arrowing out and update the GPS, the counter records that onLocationChanged is still getting called even though the screen is in the background and onPause has been called. If I go in and out of the activity with the backarrow, I can get more than two updates per GPS input send depending on how many times the activity screen is entered.
All the GPS code works but these multiple instances can't be good and they mess up other things I am trying to do, like distance traveled between two updates.
Here is what I think is the relevant parts of my code. Obviously I left out the main part but the point is that after returning to this screen after back-arrowing out then a single send of a GPS data point increments the n variable by more than one depending on how many times I have returned to the screen.
I must be doing something obvious but I can't find it.
public class Data extends Activity {
protected LocationListener ll;
protected LocationManager lm;
static int n = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.data);
LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
LocationListener ll = new mylocationlistener();
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);
}
class mylocationlistener implements LocationListener{
#Override
public void onLocationChanged(Location location) {
if (location != null){
n = n + 1;
textData.setText("\n" + n);
}
}
and
#Override
protected void onPause() {
if(lm != null) {
lm.removeUpdates(ll);
}
ll = null;
lm = null;
super.onPause();
}
The only clue I have is that if I take the lm.removeUpdates(ll) out of the if(lm != null) then the code crashes which makes me think that lm must be null and that lm.removeUpdates(ll) must not be correct but it matches the all the examples I could find as well as the Android documentation as far as I can tell.
Please help.
LocationListener ll = new mylocationlistener();
This LocationListener is local to your method onCreate().So is your LocationManager lm.So when you are removing updates its not working with the manager and listener that you declared as the class variable.
Just write as
lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
ll = new mylocationlistener(); in your onCreate().
I have been stuck on this problem for quite some time. I am working on an app that uses location quite extensively in several different Activities. Every example I have found uses a separate LocationListener in every Activity. This is not feasible in my situation.
I am wondering what is the most efficient way to keep track of the user's location across several activities. Right now I have created a service that implements LocationListener and uses a broadcast to update static lat and long fields in an Activity base class. This means that the service is always running, which isn't ideal. But if I shut down the service and restart it only when I need it, it takes time to get a good location. I need the location data in the Activity's onCreate(). It's the same if I try to implement it in the activity base class. If I constantly register the listener in onResume/onCreate and unregister it in onPause(), it takes too much time to start receiving updates. I also tried to create a service that I could bind to, so it only starts when I need a location. But I have the same problem, it takes too long to bind to the service and start getting updates.
The service that I am using now works but from everything I've read, I shouldn't be using a constantly running service for trivial things like this. But the whole point of the app is to provide relevant data based on the user's current location. So I have a service that just runs in the background and provides updates periodically. The one major problem that has caused me to reexamine the design at this point is that I recently discovered that onProviderEnabled() doesn't get called if the user starts the app without GPS turned on and then subsequently enables it. In this scenario the app has no way of recognizing that GPS was enabled so it can start listening for updates.
I thought I understood LocationManager and LocationListener from looking at the examples but I can't seem to apply it to this situation where I need location data in multiple Activities. Any help or advice would be greatly appreciated.
The way that I would typically implement this requirement is using a bound Service implementation, like the one in the Local Service Sample in the SDK Documentation. Obviously you're familiar with the advantage of the Service allowing you to create all the location code only once.
Accessing the Service through Bindings allows the Service to start and stop itself so it isn't running when your application isn't in the foreground (it will die as soon as no more Activities are bound). The key, IMO, to making this work well is to BIND the service in onStart() and UNBIND in onStop(), because those two calls overlap as you move from one Activity to another (Second Activity Starts before the First one Stops). This keeps the Service from dying when moving around inside the app, and only lets the service die when the entire application (or at least any part interested in location) leaves the foreground.
With Bindings, you don't have to pass the Location data in a Broadcast, because the Activity can call methods directly on the Service to get the latest location. However, a Broadcast would still be advantageous as a method of indicating WHEN a new update is available...but this would just become a notifier to the listening Activity to call the getLocation() method on the Service.
My $0.02. Hope that Helps!
I got the same problem and I tried to solve it with the good answer of Devunwired, but I had some troubles. I couldn't find a way to stop the service and when I finished my app the GPS-module was still running. So i found another way:
I wrote a GPS.java class:
public class GPS {
private IGPSActivity main;
// Helper for GPS-Position
private LocationListener mlocListener;
private LocationManager mlocManager;
private boolean isRunning;
public GPS(IGPSActivity main) {
this.main = main;
// GPS Position
mlocManager = (LocationManager) ((Activity) this.main).getSystemService(Context.LOCATION_SERVICE);
mlocListener = new MyLocationListener();
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
// GPS Position END
this.isRunning = true;
}
public void stopGPS() {
if(isRunning) {
mlocManager.removeUpdates(mlocListener);
this.isRunning = false;
}
}
public void resumeGPS() {
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
this.isRunning = true;
}
public boolean isRunning() {
return this.isRunning;
}
public class MyLocationListener implements LocationListener {
private final String TAG = MyLocationListener.class.getSimpleName();
#Override
public void onLocationChanged(Location loc) {
GPS.this.main.locationChanged(loc.getLongitude(), loc.getLatitude());
}
#Override
public void onProviderDisabled(String provider) {
GPS.this.main.displayGPSSettingsDialog();
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}
}
This class is used in every Activity which needs the GPS coordinates. Every Activity has to implement the following Interface (needed for the communication):
public interface IGPSActivity {
public void locationChanged(double longitude, double latitude);
public void displayGPSSettingsDialog();
}
Now my main Activity looks like that:
public class MainActivity extends Activity implements IGPSActivity {
private GPS gps;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
gps = new GPS(this);
}
#Override
protected void onResume() {
if(!gps.isRunning()) gps.resumeGPS();
super.onResume();
}
#Override
protected void onStop() {
gps.stopGPS();
super.onStop();
}
public void locationChanged(double longitude, double latitude) {
Log.d(TAG, "Main-Longitude: " + longitude);
Log.d(TAG, "Main-Latitude: " + latitude);
}
#Override
public void displayGPSSettingsDialog() {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
}
and a second one like that:
public class TEST4GPS extends Activity implements IGPSActivity{
private GPS gps;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.gps = new GPS(this);
}
#Override
public void locationChanged(double longitude, double latitude) {
Log.d("TEST", "Test-Longitude: " + longitude);
Log.d("TEST", "Test-Latitude: " + latitude);
}
#Override
protected void onResume() {
if(!gps.isRunning()) gps.resumeGPS();
super. onResume();
}
#Override
protected void onStop() {
gps.stopGPS();
super.onStop();
}
#Override
public void displayGPSSettingsDialog() {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
}
It's not as beautiful as the solution of Devunwired, but it works for me.
cya
You could have your service writing your lat & long coords to an sqlite db on change that way you dont have the service binding overhead and your coords will be accessible across all your activities.
Perhaps in your main activity you can check the GPS status and if it is turned off you can prompt the user to enable it. Once GPS is enabled start your service.
Here is a very simple and straightforward way to do it:
In your main activity:
private boolean mFinish;
#Override
public void onBackPressed() {
mFinish = true;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mFinish = false;
...
}
#Override
public void onPause(){
super.onPause();
if (mFinish) {
// remove updates here
mLocationManager.removeUpdates(mLocationListener);
}
}
This will only remove the updates listener if you press Back in your main activity, but otherwise stay on.
It's not the best way to do it, but it's a simple copy-paste solution.
Make sure you don't call location listener if it's already running (for example on screen rotate), otherwise you'll end up with multiple listeners running in the background.