Develop Reference

How to save previous gps coordinates

I am making a program in android where i get the gps coordinates when the location changes. I need to save the previous latitude and longitude whenever the location changes. Then i will be able to calculate the distance later. Can anyone help me how to save the current coordinates and the previous coordinates programmatically. Thanks. Here is my code. Ignore the buttons and timer i have to store the previous coordinates when the location changes.
package com.example.higher.myosmand;
import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.preference.PreferenceManager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Timer;
import java.util.TimerTask;
public class MainActivity extends Activity {
private LocationManager locationManager;
private LocationListener locationListener;
private Location currentLocation;
private TextView latlon;
private TextView distance;
ArrayList<String> list = new ArrayList<>();
ListView listView;
private TextView listText;
private float results[] = new float[2];
double lat;
double lon;
double currentLat;
double currentLon;
double accuracy;
double speed;
double altitude;
double time;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
latlon = (TextView) findViewById(R.id.latlon);
distance = (TextView) findViewById(R.id.distanceText);
listView = (ListView)findViewById(R.id.listView);
listText = (TextView)findViewById(R.id.listText);
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location loc) {
//locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
lat = loc.getLatitude();
lon = loc.getLongitude();
accuracy = loc.getAccuracy();
speed = loc.getSpeed();
altitude = loc.getAltitude();
time = loc.getTime();
/*currentLocation = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
currentLat = currentLocation.getLatitude();
currentLon = currentLocation.getLongitude();*/
listView.setAdapter(new ArrayAdapter<String>(MainActivity.this, R.layout.activity_simplelist, R.id.listText, list));
list.add("latitude: " + lat + " longitude: " + lon);
//list.add("speed: " + speed + " accuracy: " + accuracy);
distance.setText("size: " + list.size());
}
#Override
public void onProviderDisabled(String arg0) {
//TODO auto generated method stub
}
#Override
public void onProviderEnabled(String arg0) {
//TODO auto generated method stub
}
#Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
//TODO auto generated method stub
}
};
}
public void setMyTimer(){
Timer myTimer = new Timer();
TimerTask myTask = new TimerTask() {
#Override
public void run() {
runOnUiThread(new Runnable() {
#Override
public void run() {
listView.setAdapter(new ArrayAdapter<String>(MainActivity.this, R.layout.activity_simplelist, R.id.listText, list));
list.add("latitude: " + lat + " longitude: " + lon);
//distance.setText("Current Location:\n Latitude: " + currentLat +" Longitude: " + currentLon);
}
});
}
};
myTimer.schedule(myTask, 5000, 5000);
}
public void startButton(View view) {
//locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
latlon.setText("latitude: " + lat + " \nlongitude: " + lon + " \naccuracy: " + accuracy +
"\nspeed: " + speed + "\naltitude: " + altitude + "\ntime: " + time);
}
public void endButton(View view) {
//locationManager.removeUpdates(locationListener);
//locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
}
public void resetButton(View view) {
list.clear();
}
#Override
protected void onResume() {
super.onResume();
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
}
#Override
protected void onPause() {
super.onPause();
//locationManager.removeUpdates(locationListener);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

In an attempt to simplify embloo's answer, you can just save your current location to your previous location variable before updating to the current location in the onLocationChanged method. Like this:
#Override
public void onLocationChanged(Location location) {
mPreviousLocation = mCurrentLocation;
mCurrentLocation = location;
// update values or UI below here
}

Use this code inside your onLocationChanged method. It stores your previous location coordinates into prev variable:
private LatLng prev;
private int flag=0;
#Override
public void onLocationChanged(Location location) {
LatLng current = new LatLng(location.getLatitude(), location.getLongitude());
if(flag==0)
{
prev=current;
flag=1;
}
//Do whatever you want here
prev=current;
current = null;
}

Use SharedPreferences for simple key-value storage.
// saving
PreferenceManager.getDefaultSharedPreferences(context).edit()
.putLong("current_latitude", latitude)
.putLong("current_longitude", longitude)
.apply();
// loading
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
long latitude = prefs.getLong("current_latitude", 0);
long longitude = prefs.getLong("current_longitude", 0);

android accurate gps. calculate steps taken

the app i am creating need to use gps to keep track of how many steps the user steps has taken during excercise. if i cannot count the steps at least i wanted to calculated very accurate distance.
my code can display a map and user location as a blue dot. it did follow me but is quite inaccurate sometimes.i can get the gps to get the current location but it is not very accurate. i heard there is a new location API but i could not find an example code. i can't spot the difference between them..
the following has a lot of code that is unnecessary the reason is i decided to not include the map.
my map api v2 cannot display on emulator. blue-stack displayed a blank map and cannot enter location data. i need to use the same emulator as my team. and i know that map is not a requirement but gps calculate steps/accurate distance is a requirement.
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.support.v4.app.FragmentActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.view.Menu;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class MainActivity extends FragmentActivity implements LocationListener, Runnable, TextWatcher{
protected LocationManager locationManager;
private GoogleMap googleMap;
Button btnStartMove,btnPause,btnResume,btnStop;
//TextView Distance;
static double n=0;
Long s1,r1;
double lat1,lon1,lat2,lon2;
double dis=0.0;
MyCount counter;
Thread t1;
EditText userNumberInput;
boolean bool=false;
int count=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
if(isGooglePlay())
{
//setContentView(R.layout.activity_main);
setUpMapIfNeeded();
}
btnStartMove=(Button)findViewById(R.id.Start);//start moving
btnPause=(Button)findViewById(R.id.Pause);//pause
btnResume=(Button)findViewById(R.id.Resume);//resume
btnStop=(Button)findViewById(R.id.Stop);
userNumberInput=(EditText)findViewById(R.id.UserInput);
userNumberInput.addTextChangedListener(this);
//Distance=(TextView)findViewById(R.id.Distance);
btnStartMove.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
//start(v);
//start(v);
}
});
btnPause.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
//start(v);
}
});
btnResume.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
//start(v);
}
});
btnStop.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
//start(v);
}
});
}
#Override
public void afterTextChanged(Editable editable) {
try
{
int no = Integer.parseInt(editable.toString());
if(no >= 100)
{
editable.replace(0, editable.length(), "99");
}
}
catch(NumberFormatException e){}
}
#Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
int arg3) {
// TODO Auto-generated method stub
}
#Override
public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
// TODO Auto-generated method stub
}
private void setUpMapIfNeeded() {
if(googleMap == null)
{
Toast.makeText(MainActivity.this, "Getting map",
Toast.LENGTH_LONG).show();
googleMap =((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.displayMap)).getMap();
if(googleMap != null)
{
setUpMap();
}
}
}
private void setUpMap()
{
//Enable MyLocation Layer of Google Map
googleMap.setMyLocationEnabled(true);
//Get locationManager object from System Service LOCATION_SERVICE
//LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
//Create a criteria object to retrieve provider
Criteria criteria = new Criteria();
//Get the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
if(provider == null)
{
onProviderDisabled(provider);
}
//set map type
googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
//Get current location
Location myLocation = locationManager.getLastKnownLocation(provider);
if(myLocation != null)
{
onLocationChanged(myLocation);
}
locationManager.requestLocationUpdates(provider, 0, 0, this);
}
private boolean isGooglePlay()
{
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if (status == ConnectionResult.SUCCESS)
{
Toast.makeText(MainActivity.this, "Google Play Services is available",
Toast.LENGTH_LONG).show();
return(true);
}
else
{
GooglePlayServicesUtil.getErrorDialog(status, this, 10).show();
}
return (false);
}
#Override
public void onLocationChanged(Location myLocation) {
//Get latitude of the current location
double latitude = myLocation.getLatitude();
//Get longitude of the current location
double longitude = myLocation.getLongitude();
//Create a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
//Show the current location in Google Map
googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
//Zoom in the Google Map
googleMap.animateCamera(CameraUpdateFactory.zoomTo(20));
googleMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).title("You are here!"));
}
#Override
public void onProviderDisabled(String provider) {
Toast.makeText(MainActivity.this,
"Provider disabled by the user. GPS turned off",
Toast.LENGTH_LONG).show();
}
#Override
public void onProviderEnabled(String provider) {
Toast.makeText(MainActivity.this,
"Provider enabled by the user. GPS turned on",
Toast.LENGTH_LONG).show();
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
Toast.makeText(MainActivity.this, "Provider status changed",
Toast.LENGTH_LONG).show();
}
public void start (View v){
switch(v.getId()){
case R.id.Start:
Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null)
{
lat2=location.getLatitude();
lon2=location.getLongitude();
bool=true;
t1=new Thread(this);
t1.start();
counter= new MyCount(30000,1000);
counter.start();
}
else
{
Toast.makeText(MainActivity.this, "null location",
Toast.LENGTH_LONG).show();
}
break;
case R.id.Pause:
counter.cancel();
bool=false;
break;
case R.id.Resume:
counter= new MyCount(s1,1000);
counter.start();
bool=true;
break;
// case R.id.Distance:
// double time=n*30+r1;
// //Distance.setText("Distance:" + dis);
// Toast.makeText(MainActivity.this,"distance in metres:"+String.valueOf(dis)+"Velocity in m/sec :"+String.valueOf(dis/time)+"Time :"+String.valueOf(time),Toast.LENGTH_LONG).show();
// Toast.makeText(MainActivity.this, "Value of Count:" + String.valueOf(count),
// Toast.LENGTH_LONG).show();
// break;
case R.id.Stop:
counter.cancel();
counter= new MyCount(30000,1000);
bool = false;
}
}
public class MyCount extends CountDownTimer{
public MyCount(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
#Override
public void onFinish() {
counter= new MyCount(30000,1000);
counter.start();
n=n+1;
}
#Override
public void onTick(long millisUntilFinished) {
s1=millisUntilFinished;
r1=(30000-s1)/1000;
//e1.setText(String.valueOf(r1));
}
}
public double getDistance(double lat1, double lon1, double lat2, double lon2) {
double latA = Math.toRadians(lat1);
double lonA = Math.toRadians(lon1);
double latB = Math.toRadians(lat2);
double lonB = Math.toRadians(lon2);
double cosAng = (Math.cos(latA) * Math.cos(latB) * Math.cos(lonB-lonA)) +
(Math.sin(latA) * Math.sin(latB));
double ang = Math.acos(cosAng);
double dist = ang *6371;
return dist;
}
public static void distanceBetween (double startLatitude, double startLongitude, double endLatitude, double endLongitude, float[] results)
{
}
#Override
public void run()
{
count=6;
//LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
lat1=location.getLatitude();
lon1=location.getLongitude();
while(bool==true)
{
if(lat1!=lat2 || lon1!=lon2)
{
dis+=getDistance(lat2,lon2,lat1,lon1);
lat2=lat1;
lon2=lon1;
count =7;
//Distance.setText("Distance: " + dis + " Count: " + count);
count++;
}
}
}}

Once you have the distance, you can divide by the persons average step length, which you can let the user enter as paramter.
This will not work when making an exercise whithout moving (on a step trainer).
But for walking or running outdoors this will work.

some issue in detecting location application crashes

I am Trying to develop small application in which i am trying to Detect Location.
I am using the following code but i don't know why my application crashes. It show the application stops Unfortunately.
Here is the code. Please tell me if there is any bug and if not then please at least reply.
Thanks.
Here is the Code.
package com.project.kamani.nearby;
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import android.app.Activity;
import android.location.Address;
import android.location.Criteria;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class Map extends Activity implements LocationListener{
public GoogleMap google_map;
public List<Address> addresses;
public Geocoder geocoder;
private Location location;
private double lat;
private double lang;
private Criteria criteria;
private LocationManager location_manager;
private String provider;
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES=20;//DISTANCE IN METERS
private static final long MIN_TIME_BW_UPDATES=1000*60*1;// TAKES UPDATE AFTER 1 MINUTES
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(isGooglePlayAvailable())
{
criteria=new Criteria();
setContentView(R.layout.mapdemo);
getGoogleMap();
getUserLocation();
//Toast.makeText(this, "Latitude:"+lat+" Longitude:"+lang, Toast.LENGTH_LONG).show();
getAddress(lat,lang);
drawMarker(lat,lang);
}
}
private boolean isGooglePlayAvailable(){
int status=GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if(status==ConnectionResult.SUCCESS)
return true;
else
GooglePlayServicesUtil.getErrorDialog(status, this, 10).show();
return false;
}
private void getGoogleMap(){
if(google_map==null){
google_map=((MapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap();
}
}
private void drawMarker(double lattitude,double longitude){
google_map.clear();
google_map.setMyLocationEnabled(true);
LatLng latlng=new LatLng(lattitude, longitude);
google_map.moveCamera(CameraUpdateFactory.newLatLng(latlng));
google_map.animateCamera(CameraUpdateFactory.zoomTo(15));
LatLng currentPosition = new LatLng(lattitude,longitude);
google_map.addMarker(new MarkerOptions().position(currentPosition).snippet("Address:" + addresses.get(0).getAddressLine(0) + "City:"+ addresses.get(0).getAddressLine(1)+"Country:"+addresses.get(0).getAddressLine(2)).icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)).title("ME"));
}
private void getAddress(double lattitude,double longitude){
geocoder=new Geocoder(Map.this, Locale.getDefault());
try {
addresses=geocoder.getFromLocation(lattitude, longitude, 1);
Toast.makeText(Map.this, "Address:" + addresses.get(0).getAddressLine(0) + "City:"+ addresses.get(0).getAddressLine(1)+"Country:"+addresses.get(0).getAddressLine(2), Toast.LENGTH_LONG).show();
} catch (IOException e) {
e.printStackTrace();
}
}
private void getUserLocation(){
location_manager=(LocationManager) getSystemService(LOCATION_SERVICE);
if(location_manager!=null){
provider=location_manager.getBestProvider(criteria, true);
location=location_manager.getLastKnownLocation(provider);
location_manager.requestLocationUpdates(provider, Map.MIN_TIME_BW_UPDATES, Map.MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
lat=location.getLatitude();
lang=location.getLongitude();
}
}
#Override
public void onLocationChanged(Location location) {
google_map.clear();
drawMarker(lat, lang);
}
#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
}
}
Here is the snapshot that error i am getting in logcat.
I hope it will be helpful to solve error.
EDIT:-
If you don't want to monitor once again full code just try to view at getUserLocation method still the application stops working when i enable the GPS thanks for your support.

location is never initialized. Your are setting location as the variable that will hold the return value of getUserLocation() and it is also its parameter; both are null.

public class MainActivity extends MapActivity implements LocationListener {
private MapView mapView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Getting reference to MapView
mapView = (MapView) findViewById(R.id.map_view);
// Setting Zoom Controls on MapView
mapView.setBuiltInZoomControls(true);
// Getting LocationManager object from System Service LOCATION_SERVICE
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
// Creating a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Getting the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
// Getting Current Location
Location location = locationManager.getLastKnownLocation(provider);
if(location!=null){
onLocationChanged(location);
}
locationManager.requestLocationUpdates(provider, 20000, 0, this);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
#Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
#Override
public void onLocationChanged(Location location) {
TextView tvLocation = (TextView) findViewById(R.id.tv_location);
// Getting latitude
double latitude = location.getLatitude();
// Getting longitude
double longitude = location.getLongitude();
// Setting latitude and longitude in the TextView tv_location
tvLocation.setText("Latitude:" + latitude + ", Longitude:"+ longitude );
// Creating an instance of GeoPoint corresponding to latitude and longitude
GeoPoint point = new GeoPoint((int)(latitude * 1E6), (int)(longitude*1E6));
// Getting MapController
MapController mapController = mapView.getController();
// Locating the Geographical point in the Map
mapController.animateTo(point);
// Applying a zoom
mapController.setZoom(15);
// Redraw the map
mapView.invalidate();
// Getting list of overlays available in the map
List<Overlay> mapOverlays = mapView.getOverlays();
// Creating a drawable object to represent the image of mark in the map
Drawable drawable = this.getResources().getDrawable(R.drawable.cur_position);
// Creating an instance of ItemizedOverlay to mark the current location in the map
CurrentLocationOverlay currentLocationOverlay = new CurrentLocationOverlay(drawable);
// Creating an item to represent a mark in the overlay
OverlayItem currentLocation = new OverlayItem(point, "Current Location", "Latitude : " + latitude + ", Longitude:" + longitude);
// Adding the mark to the overlay
currentLocationOverlay.addOverlay(currentLocation);
// Clear Existing overlays in the map
mapOverlays.clear();
// Adding new overlay to map overlay
mapOverlays.add(currentLocationOverlay);
}
#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
}
}
Download Here

Determining the speed of a vehicle using GPS in android

I would like to know how to get the speed of a vehicle using your phone while seated in the vehicle using gps. I have read that the accelerometer is not very accurate. Another thing is; will GPS be accessible while seated in a vehicle. Won't it have the same effect as while you are in a building?
Here is some code I have tried but I have used the NETWORK PROVIDER instead.I will appreciate the help. Thanks...
package com.example.speedtest;
import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.Toast;
public class MainActivity extends Activity {
LocationManager locManager;
LocationListener li;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
locManager=(LocationManager)getSystemService(Context.LOCATION_SERVICE);
li=new speed();
locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, li);
}
class speed implements LocationListener{
#Override
public void onLocationChanged(Location loc) {
Float thespeed=loc.getSpeed();
Toast.makeText(MainActivity.this,String.valueOf(thespeed), Toast.LENGTH_LONG).show();
}
#Override
public void onProviderDisabled(String arg0) {}
#Override
public void onProviderEnabled(String arg0) {}
#Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {}
}
}

for more information onCalculate Speed from GPS Location Change in Android Mobile Device view this link
Mainly there are two ways to calculate the speed from mobile phone.
Calculate speed from Accelerometer
Calculate speed from GPS Technology
Unlike Accelerometer from GPS Technology if you're going to calculate speed you must enable data connection and GPS connection.
In here we are going to calculate speed using GPS connection.
In this method we using how frequency the GPS Location points are changing during single time period. Then if we have the real distance between the geo locations points we can get the speed. Because we have the distance and the time.
Speed = distance/time
But getting the distance between two location points is not very easy. Because the world is a goal in shape the distance between two geo points is different from place to place and angle to angle. So we have to use “Haversine Algorithm”
First we have to give permission for Get Location data in Manifest file
Make the GUI
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="#+id/txtCurrentSpeed"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="000.0 miles/hour"
android:textAppearance="?android:attr/textAppearanceLarge" />
<CheckBox android:id="#+id/chkMetricUnits"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Use metric units?"/>
Then make an interface to get the speed
package com.isuru.speedometer;
import android.location.GpsStatus;
import android.location.Location;
import android.location.LocationListener;
import android.os.Bundle;
public interface IBaseGpsListener extends LocationListener, GpsStatus.Listener {
public void onLocationChanged(Location location);
public void onProviderDisabled(String provider);
public void onProviderEnabled(String provider);
public void onStatusChanged(String provider, int status, Bundle extras);
public void onGpsStatusChanged(int event);
}
Implement the logic to get the speed using the GPS Location
import android.location.Location;
public class CLocation extends Location {
private boolean bUseMetricUnits = false;
public CLocation(Location location)
{
this(location, true);
}
public CLocation(Location location, boolean bUseMetricUnits) {
// TODO Auto-generated constructor stub
super(location);
this.bUseMetricUnits = bUseMetricUnits;
}
public boolean getUseMetricUnits()
{
return this.bUseMetricUnits;
}
public void setUseMetricunits(boolean bUseMetricUntis)
{
this.bUseMetricUnits = bUseMetricUntis;
}
#Override
public float distanceTo(Location dest) {
// TODO Auto-generated method stub
float nDistance = super.distanceTo(dest);
if(!this.getUseMetricUnits())
{
//Convert meters to feet
nDistance = nDistance * 3.28083989501312f;
}
return nDistance;
}
#Override
public float getAccuracy() {
// TODO Auto-generated method stub
float nAccuracy = super.getAccuracy();
if(!this.getUseMetricUnits())
{
//Convert meters to feet
nAccuracy = nAccuracy * 3.28083989501312f;
}
return nAccuracy;
}
#Override
public double getAltitude() {
// TODO Auto-generated method stub
double nAltitude = super.getAltitude();
if(!this.getUseMetricUnits())
{
//Convert meters to feet
nAltitude = nAltitude * 3.28083989501312d;
}
return nAltitude;
}
#Override
public float getSpeed() {
// TODO Auto-generated method stub
float nSpeed = super.getSpeed() * 3.6f;
if(!this.getUseMetricUnits())
{
//Convert meters/second to miles/hour
nSpeed = nSpeed * 2.2369362920544f/3.6f;
}
return nSpeed;
}
}
Combine logic to GUI
import java.util.Formatter;
import java.util.Locale;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.TextView;
public class MainActivity extends Activity implements IBaseGpsListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
this.updateSpeed(null);
CheckBox chkUseMetricUntis = (CheckBox) this.findViewById(R.id.chkMetricUnits);
chkUseMetricUntis.setOnCheckedChangeListener(new OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
// TODO Auto-generated method stub
MainActivity.this.updateSpeed(null);
}
});
}
public void finish()
{
super.finish();
System.exit(0);
}
private void updateSpeed(CLocation location) {
// TODO Auto-generated method stub
float nCurrentSpeed = 0;
if(location != null)
{
location.setUseMetricunits(this.useMetricUnits());
nCurrentSpeed = location.getSpeed();
}
Formatter fmt = new Formatter(new StringBuilder());
fmt.format(Locale.US, "%5.1f", nCurrentSpeed);
String strCurrentSpeed = fmt.toString();
strCurrentSpeed = strCurrentSpeed.replace(' ', '0');
String strUnits = "miles/hour";
if(this.useMetricUnits())
{
strUnits = "meters/second";
}
TextView txtCurrentSpeed = (TextView) this.findViewById(R.id.txtCurrentSpeed);
txtCurrentSpeed.setText(strCurrentSpeed + " " + strUnits);
}
private boolean useMetricUnits() {
// TODO Auto-generated method stub
CheckBox chkUseMetricUnits = (CheckBox) this.findViewById(R.id.chkMetricUnits);
return chkUseMetricUnits.isChecked();
}
#Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
if(location != null)
{
CLocation myLocation = new CLocation(location, this.useMetricUnits());
this.updateSpeed(myLocation);
}
}
#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 onGpsStatusChanged(int event) {
// TODO Auto-generated method stub
}
}
If you want to convert Meters/Second to kmph-1 then you need to multipl the Meters/Second answer from 3.6
Speed from kmph-1 = 3.6 * (Speed from ms-1)

GPS works fine in a vehicle. The NETWORK_PROVIDER setting might not be accurate enough to get a reliable speed, and the locations from the NETWORK_PROVIDER may not even contain a speed. You can check that with location.hasSpeed() (location.getSpeed() will always return 0).
If you find that location.getSpeed() isn't accurate enough, or it is unstable (i.e. fluctuates drastically) then you can calculate speed yourself by taking the average distance between a few GPS locations and divide by the time elapsed.

public class MainActivity extends Activity implements LocationListener {
add implements LocationListener next to Activity
LocationManager lm =(LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
this.onLocationChanged(null);
LocationManager.GPS_PROVIDER, 0, 0, The first zero stands for minTime and the second one for minDistance in which you update your values. Zero means basically instant updates which can be bad for battery life, so you may want to adjust it.
#Override
public void onLocationChanged(Location location) {
if (location==null){
// if you can't get speed because reasons :)
yourTextView.setText("00 km/h");
}
else{
//int speed=(int) ((location.getSpeed()) is the standard which returns meters per second. In this example i converted it to kilometers per hour
int speed=(int) ((location.getSpeed()*3600)/1000);
yourTextView.setText(speed+" km/h");
}
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
#Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
#Override
public void onProviderDisabled(String provider) {
}
Don't forget the Permissions
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

We can use location.getSpeed();
try {
// Get the location manager
double lat;
double lon;
double speed = 0;
LocationManager locationManager = (LocationManager)
getActivity().getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = locationManager.getBestProvider(criteria, false);
if (ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
Location location = locationManager.getLastKnownLocation(bestProvider);
try {
lat = location.getLatitude();
lon = location.getLongitude();
speed =location.getSpeed();
} catch (NullPointerException e) {
lat = -1.0;
lon = -1.0;
}
mTxt_lat.setText("" + lat);
mTxt_speed.setText("" + speed);
}catch (Exception ex){
ex.printStackTrace();
}

Print Long and Lat

I have been trying to print my lang and long coordinates for the past two days, I have chopped and changed code in order to make it work, in a bit of a muddle now and don't understand why it won't work, I am new to Android Development whilst consulting a book (Beginning Android Development) but it doesn't touch on this subject, any help would be greatly appreciated.
It compiles and I don't get any errors, however it does not print out to the EditText boxes in the application, defined in main.xml.
Here is my code for the Java file:
package com.emergency;
import android.app.Activity;
import android.location.Location;
import android.location.LocationListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.content.Context;
import android.location.LocationManager;
import android.location.Criteria;
public class EmergencyLocation extends Activity implements LocationListener {
private TextView latitudeField;
private TextView longitudeField;
private LocationManager locationManager;
private String provider;
/** Called when the activity is first created. **/
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
latitudeField = (TextView) findViewById(R.id.long_lat1);
longitudeField = (TextView) findViewById(R.id.long_lat2);
// Get the location manager
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// Define the criteria how to select the location provider -> use
// default
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
locationManager.requestLocationUpdates(provider, 0, 0, this);
Location location = locationManager.getLastKnownLocation(provider);
onLocationChanged(location);
}
#Override
protected void onDestroy() {
super.onDestroy();
locationManager.removeUpdates(this);
}
#Override
public void onLocationChanged(Location location) {
if (location != null) {
System.out.println("Provider " + provider + " has been selected.");
int lat = (int) (location.getLatitude());
int lng = (int) (location.getLongitude());
latitudeField.setText(String.valueOf(lat));
longitudeField.setText(String.valueOf(lng));
/*Toast.makeText(EmergencyLocation.this,
"Longitude " + longitudeField + "Latitude " + latitudeField, Toast.LENGTH_LONG).show();*/
//getting longitude to display in an EditText box
/*EditText lngtude = (EditText) findViewById(R.id.longitudeField);
lngtude.setText(String.valueOf(lng));
EditText lattude = (EditText) findViewById(R.id.latitudeField);
lattude.setText(String.valueOf(lat)); */
EditText lngtude = (EditText) findViewById(R.id.longitudeField);
lngtude.setText(String.valueOf(lng), TextView.BufferType.EDITABLE);
EditText lattude = (EditText) findViewById(R.id.latitudeField);
lattude.setText(String.valueOf(lat), TextView.BufferType.EDITABLE);
} else {
latitudeField.setText("Provider not available");
longitudeField.setText("Provider not available");
}
}
#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 onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button simpleBtn = (Button) findViewById(R.id.location);
simpleBtn.setOnClickListener(new View.OnClickListener() {*/
}
;

I don't believe you're using EditText.setText correctly. See this post as well.
EditText lngtude = (EditText) findViewById(R.id.longitudeField);
lngtude.setText(String.valueOf(lng), TextView.BufferType.EDITABLE);
EditText lattude = (EditText) findViewById(R.id.latitudeField);
lattude.setText(String.valueOf(lat), TextView.BufferType.EDITABLE);

You shouldn't call onLocationChanged() from code. That method runs when the location actually changes. On the emulator you have to simulate a location change, either by sending coordinates from the DDMS perspective or by using the geo fix command in a telnet session.