Develop Reference

.cameraPosition.target does not provide center of current view

I have a location marked in google map. The user has the option to change this location by dragging the map. I am using camera position to get the new location.Here is my code to get the original location:
mMap = googleMap
val addkey = intent.getStringExtra("address")
var addlocation = getLocationFromAddress(addkey) as LatLng
var mapLocation = CameraUpdateFactory.newLatLngZoom(addlocation, 18.0f)
mMap.animateCamera(mapLocation)
The getLocationFromAddress code is working fine.
The user then drags to a new location, clicks a button when done and upon confirmation the new location is accepted. I am trying to get the Latitude Longitude of the current camera position using the single line code:
addlocation = mMap.cameraPosition.target
But the code continues to return the Lat Long of old view. Where am I wrong?

Implement it like this -
private GoogleMap.OnCameraIdleListener onCameraIdleListener;
then use the camera listener to get the latitude longitude from the camera center position like this -
onCameraIdleListener = new GoogleMap.OnCameraIdleListener() {
#Override
public void onCameraIdle() {
LatLng latLng = mMap.getCameraPosition().target;
Geocoder geocoder = new Geocoder(MapsActivity.this);
try {
List<Address> addressList = geocoder.getFromLocation(latLng.latitude, latLng.longitude, 1);
if (addressList != null && addressList.size() > 0) {
String locality = addressList.get(0).getAddressLine(0);
String country = addressList.get(0).getCountryName();
if (!locality.isEmpty() && !country.isEmpty())
resutText.setText(locality + " " + country);
}
} catch (IOException e) {
e.printStackTrace();
}
}
};
Getting the address is an addition thing added here. Use it if you need it.

Chat Application with Maps

I want to build a basic chat application which includes location sharing. I proficient enough in Java, but haven't worked enough on Android Platform. How do I approach this problem and what are the steps to be taken?

Send location values latitude and longitude to the other person via chat message. You can get user's last known location by:
private double[] getGPS()
{
LocationManager lm = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
List<String> providers = lm.getProviders(true);
/* Loop over the array backwards, and if you get an accurate location, then break out the loop */
Location l = null;
for (int i = providers.size() - 1; i >= 0; i--)
{
l = lm.getLastKnownLocation(providers.get(i));
if (l != null)
break;
}
double[] gps = new double[2];
if (l != null)
{
gps[0] = l.getLatitude();
gps[1] = l.getLongitude();
}
return gps;
}

Get location (latitude / longitude) from address without city in Android

I'm trying to find the location (lat/long) of a street address w/o city - such as "123 Main St." - closest to the current location. This functionality is built into the Google Maps app as well as the iOS maps api, so it's surprising to find it missing for Android - e.g. calling Geocoder.getFromLocation() and have the platform insert a reference point. I have tried several solutions, the following is the best, but still feels inferior.
I make calls to Geocoder.getFromLocationName() with lower-left and upper-right coord. Calls are made beginning with a 10kmx10km area around the current location, and are repeated (30x30, 100x100, and then without the bounding box parameters)until some Addresses are returned. When multiple addresses are returned, the closest is calculated and used:
UPDATE: This approach seemed like it would be inefficient for easily found addresses outside the bounds. E.g. "New york, NY" or "Boston" searched from the west coast - requiring 3 bounded and 1 unbounded call to Geocoder.getFromLocation(). However, unexpectidly, the correct lat/lng is returned for NYC and Boston, on the first call, with tightest bounds here in CA. Google is being smart and ignoring the bounds for us. This may cause problems for some, but it is great for this approach.
package com.puurbuy.android;
import java.io.IOException;
import java.util.List;
import android.content.Context;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.os.AsyncTask;
import android.util.Log;
public class GeocoderRunner extends AsyncTask<String, Void, Address> {
final static double LON_DEG_PER_KM = 0.012682308180089;
final static double LAT_DEG_PER_KM =0.009009009009009;
final static double[] SEARCH_RANGES = {10, 50,800,-1}; //city, region, state, everywhere
private Context mContext;
private GeocoderListener mListener;
private Location mLocation;
public GeocoderRunner(Context context, Location location,
GeocoderListener addressLookupListener) {
mContext = context;
mLocation = location;
mListener = addressLookupListener;
}
#Override
protected Address doInBackground(String... params) {
Geocoder geocoder = new Geocoder(mContext);
List<Address> addresses = null;
//reference location TODO handle null
double lat = mLocation.getLatitude();
double lon = mLocation.getLongitude();
int i = 0;
try {
//loop through SEARCH_RANGES until addresses are returned
do{
//if range is -1, call getFromLocationName() without bounding box
if(SEARCH_RANGES[i] != -1){
//calculate bounding box
double lowerLeftLatitude = translateLat(lat,-SEARCH_RANGES[i]);
double lowerLeftLongitude = translateLon(lon,SEARCH_RANGES[i]);
double upperRightLatitude = translateLat(lat,SEARCH_RANGES[i]);
double upperRightLongitude = translateLon(lon,-SEARCH_RANGES[i]);
addresses = geocoder.getFromLocationName(params[0], 5, lowerLeftLatitude, lowerLeftLongitude, upperRightLatitude, upperRightLongitude);
} else {
//last resort, try unbounded call with 20 result
addresses = geocoder.getFromLocationName(params[0], 20);
}
i++;
}while((addresses == null || addresses.size() == 0) && i < SEARCH_RANGES.length );
} catch (IOException e) {
Log.i(this.getClass().getSimpleName(),"Gecoder lookup failed! " +e.getMessage());
}
if(addresses == null ||addresses.size() == 0)
return null;
//If multiple addresses were returned, find the closest
if(addresses.size() > 1){
Address closest = null;
for(Address address: addresses){
if(closest == null)
closest = address;
else
closest = getClosest(mLocation, closest,address);//returns the address that is closest to mLocation
}
return closest;
}else
return addresses.get(0);
}
#Override
protected void onPostExecute(Address address) {
if(address == null)
mListener.lookupFailed();
else
mListener.addressReceived(address);
}
//Listener callback
public interface GeocoderListener{
public void addressReceived(Address address);
public void lookupFailed();
}
//HELPER Methods
private static double translateLat(double lat, double dx){
if(lat > 0 )
return (lat + dx*LAT_DEG_PER_KM);
else
return (lat - dx*LAT_DEG_PER_KM);
}
private static double translateLon(double lon, double dy){
if(lon > 0 )
return (lon + dy*LON_DEG_PER_KM);
else
return (lon - dy*LON_DEG_PER_KM);
}
private static Address getClosest(Location ref, Address address1, Address address2){
double xO = ref.getLatitude();
double yO = ref.getLongitude();
double x1 = address1.getLatitude();
double y1 = address1.getLongitude();
double x2 = address2.getLatitude();
double y2 = address2.getLongitude();
double d1 = distance(xO,yO,x1,y1);
double d2 = distance(xO,yO,x2,y2);
if(d1 < d2)
return address1;
else
return address2;
}
private static double distance(double x1, double y1, double x2, double y2){
return Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2) );
}
}
Perhaps this is the best solution, but I was wondering if there was a way to do this in a single call.

You code looks too complicated, here is much easier way:
String searchPattern = "123 Main St."
LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
//I use last known location, but here we can get real location
Location lastKnownLocation = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
List<Address> addresses = null;
try {
//trying to get all possible addresses by search pattern
addresses = (new Geocoder(this)).getFromLocationName(searchPattern, Integer.MAX_VALUE);
} catch (IOException e) {
}
if (addresses == null || lastKnownLocation == null) {
// location service unavailable or incorrect address
// so returns null
return null;
}
Address closest = null;
float closestDistance = Float.MAX_VALUE;
// look for address, closest to our location
for (Address adr : addresses) {
if (closest == null) {
closest = adr;
} else {
float[] result = new float[1];
Location.distanceBetween(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude(), adr.getLatitude(), adr.getLongitude(), result);
float distance = result[0];
if (distance < closestDistance) {
closest = adr;
closestDistance = distance;
}
}
}
return closest; //here can be null if we did not find any addresses by search pattern.

I tried Jin35's suggestion and increased the max_results of Geocoder.getFromLocationName(), but the results were not desirable. Firstly the large max_result, unbounded call took much longer (2.5x - 7x = 1 - 6 seconds) than the 5 result, geocoord bounded call on my emulator. Perhaps realworld would be faster and this factor becomes less significant.
The killer was no matter if the max_results were 50 or 100, only 20 results came back everytime. Seems Google is limiting the results on the server-side. The closest "123 Main St" was not amoung those 20 results for me - Tested from Mt View, CA and was returned Oakley, CA.
Unless there is another method other than Geocoder.getFromLocationName() for doing address lookup, or a better way to use bounding coord, I will accept my own original answer.

getFromLocationName(String locationName, int maxResults, double lowerLeftLatitude, double lowerLeftLongitude, double upperRightLatitude, double upperRightLongitude)

GPS - Getting the distance,time while running and walking

i have a situation where i need to use GPS technique.
i need to find the distance between two points when the person is walking.
When the person starts walking he will click on Start button and when he stops he clicks on stop button
after this it should show him
1.time taken
2.Distance travelled in Kms.
3.from where to where(places name) eg: a to b
Do i need to have google maps for this?
I saw the code here link to get the current location which gives me latitude longitude.
please help how to go with this
**
Edited:
**
This is the code i am using
private EditText editTextShowLocation;
private Button buttonGetLocation;
private ProgressBar progress;
private LocationManager locManager;
private LocationListener locListener = new MyLocationListener();
private boolean gps_enabled = false;
private boolean network_enabled = false;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
editTextShowLocation = (EditText) findViewById(R.id.editTextShowLocation);
progress = (ProgressBar) findViewById(R.id.progressBar1);
progress.setVisibility(View.GONE);
buttonGetLocation = (Button) findViewById(R.id.buttonGetLocation);
buttonGetLocation.setOnClickListener(this);
locManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
}
#Override
public void onClick(View v) {
progress.setVisibility(View.VISIBLE);
// exceptions will be thrown if provider is not permitted.
try {
gps_enabled = locManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch (Exception ex) {
}
try {
network_enabled = locManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
} catch (Exception ex) {
}
// don't start listeners if no provider is enabled
if (!gps_enabled && !network_enabled) {
AlertDialog.Builder builder = new Builder(this);
builder.setTitle("Attention!");
builder.setMessage("Sorry, location is not determined. Please enable location providers");
builder.setPositiveButton("OK", this);
builder.setNeutralButton("Cancel", this);
builder.create().show();
progress.setVisibility(View.GONE);
}
if (gps_enabled) {
locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locListener);
}
if (network_enabled) {
locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locListener);
}
}
class MyLocationListener implements LocationListener {
#Override
public void onLocationChanged(Location location) {
if (location != null) {
// This needs to stop getting the location data and save the battery power.
locManager.removeUpdates(locListener);
String londitude = "Londitude: " + location.getLongitude();
String latitude = "Latitude: " + location.getLatitude();
String altitiude = "Altitiude: " + location.getAltitude();
String accuracy = "Accuracy: " + location.getAccuracy();
String time = "Time: " + location.getTime();
editTextShowLocation.setText(londitude + "\n" + latitude + "\n" + altitiude + "\n" + accuracy + "\n" + time);
progress.setVisibility(View.GONE);
}
}
#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
public void onClick(DialogInterface dialog, int which) {
if(which == DialogInterface.BUTTON_NEUTRAL){
editTextShowLocation.setText("Sorry, location is not determined. To fix this please enable location providers");
}else if (which == DialogInterface.BUTTON_POSITIVE) {
startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
}
}
It is showing the Logitude Latitude which i am entering from emulator control.
In this i am manually entering the details of longitude and latitude
by going to window->showview->other->emulator control for testing in the emulator
but what i need is i will have two edittext where i enter the place name(A) and (B)
it should give me the distance
please help

try using Google Distance Matrix Api
https://developers.google.com/maps/documentation/distancematrix/

You can use currentTimeinMillis() to get your start and end time for your journey.
You can then use the formulas explained here to find the distance and lastly you will have to use a reverse geocoding service such as Nominatim to be able to get the address of a place from your GPS coordinates.
That being said, the distance formula will get you the distance between one point and the next, not the actual displacement. If this is not what you need, but rather you want the actual distance travelled you will need to calculate this value at a shorter interval.

You can find out the distance between two locations(in terms of latitude and longitude) by making use of Spherical Trigonometry
Coming to time make use of simple date objects and compare the startTime and endTime.
(OR)
You can get approximate distance using below code
double distance;
Location locationA = new Location("point A");
locationA.setLatitude(latA);
locationA.setLongitude(lngA);
Location locationB = new Location("point B");
locationB.setLatitude(latB);
LocationB.setLongitude(lngB);
distance = locationA.distanceTo(locationB);

For getting the distance between 2points(A to B) there is a function called distanceTo in android.
For e.g.
double distance = startLocation.distanceTo(finishLocation)/1000;
For time taken as npinti said you can use currentTimeinMillis() or you can also use Timer and show it to user when he clicks on start button. Its just like stopwatch.
Edited
Place A - New York
Place B - Paris
In this case you first need to convert the string into Location(i.e you need latitude & longitude). For that you have use the concept of Geocoding.
List<Address> foundGeocode = null;
foundGeocode = new Geocoder(this).getFromLocationName("address here", 1);
foundGeocode.get(0).getLatitude(); //getting latitude
foundGeocode.get(0).getLongitude();//getting longitude
After that you can calculate the distance from the distanceTo method.
Hope this will help....

I suppose the question is one of walking..
Are you walking on the streets, or as the crow flies?
If it's streets, and your connected to the net, use google's api.. It calculates routing based on two points and returns XML.. Should be easy enough to figure out.
If it's crow flies.. well then, just do (a*a) + (b*b) = (c*c) this is by far the easier..
You could have your user tap for major turns.. Or you could keep a runnable running every 10 seconds from when they hit start, and plot the points. Still a*a+b*b=c*c but just a bunch of steps.
Of course you'd have to run it in a service.. And given the choice I'd go with that option. You could adjust the cycle time based on speed traveled. Faster would be smaller pauses.
It requires less on your dataplan.
EDIT
Ah.. I see what you're looking for. Tis not what I thought you were asking for.
Simplify.. convert lat/long to GPS. and then do simple math on the last point stored
void addDistance()
{
newX = ...
newY = ...
deltaX = absolute(m_oldX - newX)
deltaY = absolute(m_oldY = newY)
m_distance += sqrt(deltaX^2 + deltaY^2);
m_oldX = newX;
m_oldY = newY;
}
void startOver()
{
newX = ...
newY = ...
m_distance = 0;
m_oldX = newX;
m_oldY = newY;
}

How to get the latitude and longitude or gps data quickly while we are indoor in an android phone?

I'm trying to get the latitude and longitude information from an android phone through GPS, when i'm outdoor or under the sky directly i'm able to get the values instantly but when i'm indoor or inside a room its taking more than a minute to get the values. Can anyone help me in getting this values fastly when I'm using my app inside a room.
I'm using the following code in getting the values:
LocationManager locManager;
locManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,1000L,500.0f,
locationListener);
Location location = locManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
and
private final LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
EditText myLocationText = (EditText)findViewById(R.id.editText1);
EditText myLocationText1 = (EditText)findViewById(R.id.editText2);
String latString = "";
String LongString = "";
if (location != null) {
double lat = location.getLatitude();
double lng = location.getLongitude();
latString = "" + lat;
LongString ="" + lng;
} else {
latString = "No location found";
LongString = "No location found";
}
myLocationText.setText(""+ latString);
myLocationText1.setText(""+ LongString);
}
Is there any other way in getting the GPS values other than using LocationManager??

You can get the last known location, and it's quite fast:
/**
* Gets the last known location.
*
* #param locationManager the location manager
* #return the last known location
*/
public static Location getLastKnownLocation(LocationManager locationManager)
{
Location bestResult = null;
float bestAccuracy = 10000;
long bestTime = 0;
List<String> matchingProviders = locationManager.getAllProviders();
for (String provider: matchingProviders) {
Log.d("LOCATION", "Provider: " + provider);
Location location = locationManager.getLastKnownLocation(provider);
Log.d("LOCATION", "Location found? "+ (location==null?"NO":"YES"));
if (location != null) {
float accuracy = location.getAccuracy();
long time = location.getTime();
Log.d("LOCATION", "Acc: "+ String.valueOf(accuracy) + " -- Time: " + String.valueOf(time));
if ((time > minTime && accuracy < bestAccuracy)) {
bestResult = location;
bestAccuracy = accuracy;
bestTime = time;
}
else if (time < minTime &&
bestAccuracy == Float.MAX_VALUE && time > bestTime){
bestResult = location;
bestTime = time;
}
}
}
Log.d("LOCATION", "BEST FOUND? "+ (bestResult==null?"NO":"YES"));
return bestResult;
}

You can get the last known location of the device using the following method in LocationManager, this is the location that has been last found system-wide.
This method is the key:
Location lastKnownLocation = locationManager.getLastKnownLocation(locationProvider);
See for more details Obtaining User Location

If you are indoors, you would be better of using LocationManager.NETWORK_PROVIDER as you are unlikely to get a signal inside. You could also use getLastKnownLocation(), but this may be non existent or out of date.

If you want get position in a room, gps provider is slowly. You can try changing:
locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,1000L,500.0f,
locationListener);
Location location = locManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
By:
locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,1000L,500.0f,
locationListener);
And you will receive location in 'public void onLocationChanged(Location location)' method.

I used Network provider to fetch the Co-Ordinates and it is always much faster inside the house in living room. But when I try the same in the Basement area, it doesn't fetch the coordinates at all though I waited almost couple of minutes.
Note: I could able to make a call from basement area and I am also able to browse as well..