Develop Reference

How can I get array of available routing LatLng between Source LatLng and destination LatLng?

I wanted to add some checkpoints(Marker) into Google map between the Source and destination as per available route in my Android App.

Check this Google Maps tutorial HERE.
On the step 4, you parse a JSON which contains the different routes. From each route you can get the points with Lat and Lng values.

public class PathToDestination {
private GoogleMap mMap;
private Context context;
private static final String API_KEY = "your key";
private String pathColor = "#05b1fb";//default blue color
private int pathWidth = 5;//default is 5
private Polyline line;
private PolylineOptions polylineOptions;
public PathToDestination(Context context, GoogleMap mMap) {
this.context = context;
this.mMap = mMap;
}
public void setPathColor(String pathColor) {
this.pathColor = pathColor;
}
public void setPathWidth(int pathWidth) {
this.pathWidth = pathWidth;
}
public void drawPathBetween(#MapManager.PathMode int mode, double sourcelat, double sourcelog, double destlat, double destlog) {
drawPathBetween(mode, sourcelat, sourcelog, destlat, destlog, null);
}
public void drawPathBetween(#MapManager.PathMode int mode, double sourcelat, double sourcelog, double destlat, double destlog, MapModel[] waypoints) {
String urlStr = makeURL(mode, sourcelat, sourcelog, destlat, destlog, waypoints);
new ConnectAsyncTask(urlStr).execute();
}
/*private String makeURL(double sourcelat, double sourcelog, double destlat, double destlog) {
return makeURL(sourcelat, sourcelog, destlat, destlog, );
}*/
private String makeURL(#MapManager.PathMode int mode, double sourcelat, double sourcelog, double destlat, double destlog, MapModel... waypoints) {
StringBuilder urlString = new StringBuilder();
urlString.append("https://maps.googleapis.com/maps/api/directions/json");
urlString.append("?origin=");// from
urlString.append(Double.toString(sourcelat));
urlString.append(",");
urlString.append(Double.toString(sourcelog));
if (waypoints != null && waypoints.length > 0) {
urlString.append("&waypoints=");// waypoints
for (int i = 0; i < waypoints.length; i++) {
MapModel coordinate = waypoints[i];
urlString.append(coordinate.getLatitude());
urlString.append(",");
urlString.append(coordinate.getLongitude());
if (i < waypoints.length - 1) {
urlString.append("|");
}
}
}
urlString.append("&destination=");// to
urlString.append(Double.toString(destlat));
urlString.append(",");
urlString.append(Double.toString(destlog));
urlString.append("&sensor=false");
urlString.append("&mode=" + mode);
urlString.append("&alternatives=true");
urlString.append("&key=" + API_KEY);
return urlString.toString();
}
private void drawPath(String result) {
try {
//Tranform the string into a json object
final JSONObject json = new JSONObject(result);
JSONArray routeArray = json.getJSONArray("routes");
JSONObject routes = routeArray.getJSONObject(0);
JSONObject overviewPolylines = routes.getJSONObject("overview_polyline");
String encodedString = overviewPolylines.getString("points");
List<LatLng> list = null;
if (polylineOptions == null) {
polylineOptions = new PolylineOptions()
.width(pathWidth)
.color(Color.parseColor(pathColor)) //Google maps blue color
.geodesic(true);
}
list = decodePoly(encodedString);
polylineOptions.addAll(list);
if (line == null) {
line = mMap.addPolyline(polylineOptions);
}
line.setPoints(list);
/*
for(int z = 0; z<list.size()-1;z++){
LatLng src= list.get(z);
LatLng dest= list.get(z+1);
Polyline line = mMap.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude, dest.longitude))
.width(2)
.color(Color.BLUE).geodesic(true));
}
*/
} catch (JSONException e) {
e.printStackTrace();
}
}
public void drawPathFromEncodedPolyline(String encodedPolyline) {
// try {
//Tranform the string into a json object
// final JSONObject json = new JSONObject(result);
// JSONArray routeArray = json.getJSONArray("routes");
// JSONObject routes = routeArray.getJSONObject(0);
// JSONObject overviewPolylines = routes.getJSONObject("overview_polyline");
// String encodedString = overviewPolylines.getString("points");
List<LatLng> list = decodePoly(encodedPolyline);
Polyline line = mMap.addPolyline(new PolylineOptions()
.addAll(list)
.width(5)
.color(Color.parseColor("#05b1fb"))//Google maps blue color
.geodesic(true)
);
/*
for(int z = 0; z<list.size()-1;z++){
LatLng src= list.get(z);
LatLng dest= list.get(z+1);
Polyline line = mMap.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude, dest.longitude))
.width(2)
.color(Color.BLUE).geodesic(true));
}
*/
// } catch (JSONException e) {
// e.printStackTrace();
// }
}
private List<LatLng> decodePoly(String encoded) {
List<LatLng> poly = new ArrayList<LatLng>();
int index = 0, len = encoded.length();
int lat = 0, lng = 0;
while (index < len) {
int b, shift = 0, result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lng += dlng;
LatLng p = new LatLng((((double) lat / 1E5)),
(((double) lng / 1E5)));
poly.add(p);
}
return poly;
}
private class ConnectAsyncTask extends AsyncTask<Void, Void, String> {
private ProgressDialog progressDialog;
String url;
ConnectAsyncTask(String urlPass) {
url = urlPass;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
if ((Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 &&
!((Activity) context).isDestroyed()) ||
!((Activity) context).isFinishing()) {
progressDialog = new ProgressDialog(context);
// progressDialog.setMessage("Fetching route, Please wait...");
// progressDialog.setIndeterminate(true);
// progressDialog.show();
}
}
#Override
protected String doInBackground(Void... params) {
HttpURLConnection conn = null;
StringBuilder jsonResults = new StringBuilder();
try {
URL url = new URL(this.url);
conn = (HttpURLConnection) url.openConnection();
InputStreamReader in = new InputStreamReader(conn.getInputStream());
// Load the results into a StringBuilder
int read;
char[] buff = new char[1024];
while ((read = in.read(buff)) != -1) {
jsonResults.append(buff, 0, read);
}
} catch (MalformedURLException e) {
return jsonResults.toString();
} catch (IOException e) {
return jsonResults.toString();
} finally {
if (conn != null) {
conn.disconnect();
}
}
return jsonResults.toString();
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (progressDialog != null) {
progressDialog.hide();
}
if (result != null) {
drawPath(result);
}
}
}
public void clearRoute() {
if (line != null) {
line.remove();
}
line = null;
polylineOptions = null;
}
}
Here MapModel is an interface
public interface MapModel {
double getLatitude();
double getLongitude();
}
If you want the list of LatLng you can easily get that from
drawPathFromEncodedPolyline(String encodedPolyline)
method.
You can look here for other map functions.

Adding polylines in asynctask android

i'm having performance issues adding polylines and thought that maybe it'll be possible to add them in a separate class extending AsyncTask. However as i learned that UI elements can't be added in such way (and polylines are UI elements).
Why i'm having performance issues while drawing polylines? Well, my polylines are drawn not from pos A to pos B but from my current location to destination (which is hardcoded for the sake of application atm). So the polylines are drawn when onLocationChange listener is executed and thus my application requires lots of proccessing power.
Any ideas how to use AsyncTask on this occasion?
This is the main class:
mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {
#Override
public void onMyLocationChange(Location arg0) {
// Get positions!
currentPOS = new LatLng(arg0.getLatitude(), arg0.getLongitude());
LatLng dst = new LatLng(58.378249, 26.714673);
CameraUpdate yourLocation = CameraUpdateFactory.newLatLngZoom(currentPOS, 13);
mMap.animateCamera(yourLocation);
mMap.addMarker(new MarkerOptions().position(dst).title("SCHOOL!"));
/*
// Remove comments to add marker to Liivi 2!
mMap.addMaker(new MarkerOptions().position(currentPOS).title("My POS"));
*/
if (currentPOS != null) {
//This is supposed to show directions
DirectionAPI directionAPI = new DirectionAPI(currentPOS, dst);
GoogleResponse googleResponse = null;
try {
googleResponse = (GoogleResponse) directionAPI.execute().get();
} catch (InterruptedException e) {
Log.e("CATCH","INTERRUPDED");
e.printStackTrace();
} catch (ExecutionException e) {
Log.e("CATCH","EXECUTIONEXCEPTION");
e.printStackTrace();
}
if (googleResponse.isOk()){
DrivingDirection drivingDirection = new DrivingDirection(googleResponse.getJsonObject());
polyline = drivingDirection.getTotalPolyline();
new drawPath(mMap,polyline).execute();
}
}
}
});
This is the Async for path drawing (which will result in an error due to UI conflict):
import android.graphics.Color;
import android.os.AsyncTask;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Polyline;
import com.google.android.gms.maps.model.PolylineOptions;
import java.util.ArrayList;
/**
* Created by Kevin on 7.10.2015.
*/
public class drawPath extends AsyncTask{
private static ArrayList<LatLng> polyline;
private static GoogleMap mMap;
public drawPath(GoogleMap map, ArrayList<LatLng> polyline){
this.mMap = map;
this.polyline = polyline;
}
#Override
protected Object doInBackground(Object[] params) {
for (int i = 0; i < polyline.size() - 1; i++) {
LatLng src = polyline.get(i);
LatLng dest = polyline.get(i + 1);
// mMap is the Map Object
Polyline line = mMap.addPolyline(
new PolylineOptions().add(
new LatLng(src.latitude, src.longitude),
new LatLng(dest.latitude,dest.longitude)
).width(2).color(Color.BLUE).geodesic(true)
);
}
return null;
}
}

I solved this issue in a way that i did not add every polyline map separately but whole polyline. For example, before i had my location about 4km away from destination and it had 280 polylines between. On every onLocationChange these polylines were drawn one-by-one to map. Now they're all added at once - AsyncTask will create polylines in the background and in the post-execute they will be added.
#Override
protected Object doInBackground(Object[] params) {
PolylineOptions options = new PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
for (int z = 0; z < polyline.size(); z++) {
LatLng point = polyline.get(z);
options.add(point);
}
return options;
}
protected void onPostExecute(Object result) {
Polyline line = mMap.addPolyline((PolylineOptions) result);
}

you can use this code
ublic class DrawrootTask extends AsyncTask<String, String, String> {
private Context context;
public static boolean flagCompleted = false;
private GoogleMap googleMap;
private double source_lat = 0.0;
private double source_long = 0.0;
private double dest_lat = 0.0;
private double dest_long = 0.0;
Userdata userdata;
String tag = "DrawRootTask";
private ProgressDialog progressDialog;
public static double dist, time;
private Polyline line;
String distanceText = "";
String durationText = "";
public DrawrootTask(Context context, LatLng source, LatLng destination,
GoogleMap googleMap) {
source_lat = source.latitude;
source_long = source.longitude;
dest_lat = destination.latitude;
dest_long = destination.longitude;
this.googleMap = googleMap;
this.context = context;
userdata = Userdata.getinstance(context);
}
protected void onPreExecute() {
// // TODO Auto-generated method stub
super.onPreExecute();
progressDialog = new ProgressDialog(context);
progressDialog.setMessage(context.getResources().getString(
R.string.please_wait));
progressDialog.setIndeterminate(true);
progressDialog.show();
}
#Override
protected String doInBackground(String... params) {
String json = "";
// constructor
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.googleapis.com/maps/api/directions/json");
HashMap<String, String> keyValue = new HashMap<String, String>();
urlString.append("?origin=");// from
urlString.append(Double.toString(source_lat));
urlString.append(",");
urlString.append(Double.toString(source_long));
urlString.append("&destination=");// to
urlString.append(Double.toString(dest_lat));
urlString.append(",");
urlString.append(Double.toString(dest_long));
urlString.append("&sensor=false&mode=driving&alternatives=true");
// defaultHttpClient
String url = urlString.toString();
FetchUrl fetchurl = new FetchUrl();
json = fetchurl.fetchUrl(url, keyValue);
Log.e("Buffer Error", json);
return json;
}
#Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
try {
progressDialog.dismiss();
final JSONObject json = new JSONObject(result);
JSONArray routeArray = json.getJSONArray("routes");
JSONObject routes = routeArray.getJSONObject(0);
JSONObject overviewPolylines = routes
.getJSONObject("overview_polyline");
String encodedString = overviewPolylines.getString("points");
List<LatLng> list = decodePoly(encodedString);
for (int z = 0; z < list.size() - 1; z++) {
LatLng src = list.get(z);
LatLng dest = list.get(z + 1);
line = googleMap.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude),
new LatLng(dest.latitude, dest.longitude))
// .width(8).color(Color.BLUE).geodesic(true));
.width(8)
.color(context.getResources().getColor(
R.color.actionbar_color)).geodesic(true));
Log.i("draw root", "" + "" + line.toString());
}
JSONArray legs = routes.getJSONArray("legs");
JSONObject steps = legs.getJSONObject(0);
JSONObject duration = steps.getJSONObject("duration");
JSONObject distance = steps.getJSONObject("distance");
distanceText = distance.getString("text");
durationText = duration.getString("text");
Log.i("draw root", "" + distance.toString());
dist = Double.parseDouble(distance.getString("text").replaceAll(
"[^\\.0123456789]", ""));
time = Double.parseDouble(duration.getString("text").replaceAll(
"[^\\.0123456789]", ""));
userdata.setDistance(distanceText);
userdata.setTime(durationText);
Log.d(tag, "distace is " + dist + " time is " + time);
flagCompleted = true;
} catch (JSONException e) {
Log.d("draw root", "" + e);
}
}
private List<LatLng> decodePoly(String encoded) {
List<LatLng> poly = new ArrayList<LatLng>();
int index = 0, len = encoded.length();
int lat = 0, lng = 0;
while (index < len) {
int b, shift = 0, result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lng += dlng;
LatLng p = new LatLng((((double) lat / 1E5)),
(((double) lng / 1E5)));
poly.add(p);
}
return poly;
}
}

Android app that shows path between points along with current location

I'm trying to create an Android application that takes in an origin and destination and works along the lines of a GPS.
I was wondering if it was possible (through Google APIs) to display a map that shows the path between point A and B but also shows your current location on top of that path using GPS. I have seen tutorials and articles on how to display just the path between two points using Google directions and maps API but not combining that with your current location dot.
I have not really started this project yet because I am trying to figure out how to best approach this. Any help, tutorials, examples, suggestions will be appreciated!

You must get the your current latitude and longitude first. You can check the link for the same in the below link
http://developer.android.com/guide/topics/location/strategies.html
You must fetch the latitude and longitudes between source and destination. Which should be done using asynctask.
new connectAsyncTask().execute()
The asynctask class
private class connectAsyncTask extends AsyncTask<Void, Void, Void>{
private ProgressDialog progressDialog;
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = new ProgressDialog(MainActivity.this);
progressDialog.setMessage("Fetching route, Please wait...");
progressDialog.setIndeterminate(true);
progressDialog.show();
}
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
fetchData();
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if(doc!=null){
NodeList _nodelist = doc.getElementsByTagName("status");
Node node1 = _nodelist.item(0);
String _status1 = node1.getChildNodes().item(0).getNodeValue();
if(_status1.equalsIgnoreCase("OK")){
Toast.makeText(MainActivity.this,"OK" , 1000).show();
NodeList _nodelist_path = doc.getElementsByTagName("overview_polyline");
Node node_path = _nodelist_path.item(0);
Element _status_path = (Element)node_path;
NodeList _nodelist_destination_path = _status_path.getElementsByTagName("points");
Node _nodelist_dest = _nodelist_destination_path.item(0);
String _path = _nodelist_dest.getChildNodes().item(0).getNodeValue();
List<LatLng> points = decodePoly(_path);
for (int i = 0; i < points.size() - 1; i++) {
LatLng src = points.get(i);
LatLng dest = points.get(i + 1);
// Polyline to display the routes
Polyline line = mMap.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude),
new LatLng(dest.latitude,dest.longitude))
.width(2).color(Color.BLUE).geodesic(true))
}
progressDialog.dismiss();
}else{
// Unable to find route
}
}else{
// Unable to find route
}
}
}
DecodePoly function
private List<LatLng> decodePoly(String encoded) {
List<LatLng> poly = new ArrayList<LatLng>();
int index = 0, len = encoded.length();
int lat = 0, lng = 0;
while (index < len) {
int b, shift = 0, result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lng += dlng;
LatLng p = new LatLng((((double) lat / 1E5)), (((double) lng / 1E5)));
poly.add(p);
}
return poly;
}
Fetch data
Here flati and flongi is the source latitude and longitude
dlati and dlongi is the destination latitude and longitude
Document doc = null;
private void fetchData()
{
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.google.com/maps/api/directions/xml?origin=");
urlString.append( Double.toString(flati));
urlString.append(",");
urlString.append( Double.toString(flongi));
urlString.append("&destination=");//to
urlString.append( Double.toString(dlati));
urlString.append(",");
urlString.append( Double.toString(dlongi));
urlString.append("&sensor=true&mode=walking");
Log.d("url","::"+urlString.toString());
HttpURLConnection urlConnection= null;
URL url = null;
try
{
url = new URL(urlString.toString());
urlConnection=(HttpURLConnection)url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.connect();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = (Document) db.parse(urlConnection.getInputStream());//Util.XMLfromString(response);
}catch (MalformedURLException e){
e.printStackTrace();
}catch (IOException e){
e.printStackTrace();
}catch (ParserConfigurationException e){
e.printStackTrace();
}
catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

You can get an idea on how to implement Google Map API V2 in your application by reading this guide I wrote on this topic:
Google Map API V2
Then you could implement the driving navigation root using this answer I gave here:
Draw driving route between 2 GeoPoints on GoogleMap SupportMapFragment
and to find your current location you should implement a loicationListener, you can see an example here:
http://about-android.blogspot.co.il/2010/04/find-current-location-in-android-gps.html

adding Geopoints to ItemizedOverlay array failed

I've been trying to add my GeoPoints to the itemizedOverlay Array in order to draw the points on the map. Unfortunately, the app crashing at this point.
My Code:
package com.example.phooogle;
public class GoogleMapsAppActivity extends MapActivity {
private MapView mapView;
private MapController mc;
private MyLocationOverlay myLocationOverlay;
private myMapService mms;
String[] ms;
private LocationManager lm;
private LocationListener locationListener;
private MyLocationOverlay myLocOverlay;
GeoPoint p;
GeoPoint progress1[];
List<GeoPoint> geoPointsArray = new ArrayList<GeoPoint>();
int latitude;
int longitude;
private ProgressDialog progress;
MotionEvent event;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cool_map);
progress= new ProgressDialog(this);
progress.setIndeterminate(true);
progress.setMessage("I am thinking");
InitTask init_task= new InitTask();
init_task.execute("144.963620993985", "-37.8140023779914", "20", "Litter Bin");
try {
String[] arrs = init_task.strArr2;
//Log.d(" print points", " Array Size " + arrs.length);
Drawable makerDefault = this.getResources().getDrawable(R.drawable.poke);
MirItemizedOverlay itemizedOverlay = new MirItemizedOverlay(makerDefault);
for(int j=0; j<arrs.length ;j++)
{
double y =0;
double x =0;
if(j == 1)
{
/// x
//Log.d("Results", "2If statem " + strArr2[j] );
x = Double.parseDouble(arrs[j]);
y = Double.parseDouble(arrs[j+1]);
//Log.d(" print points", "lat " + x + " long" + y);
itemizedOverlay.addOverlayItem((int) x , (int) y , "La trobe");
mapView.getOverlays().add(itemizedOverlay );
}
}
MapController mc = mapView.getController();
mc.setCenter(new GeoPoint((int) (1E6 * -37.720754), (int) (1E6 * 145.048798))); // Some where .
mc.zoomToSpan(itemizedOverlay.getLatSpanE6(), itemizedOverlay.getLonSpanE6());
} finally {}
initMap();
initMyLocation();
// theRouteDraw();
/*
Drawable makerDefault = this.getResources().getDrawable(R.drawable.poke);
MirItemizedOverlay itemizedOverlay = new MirItemizedOverlay(makerDefault);
itemizedOverlay.addOverlayItem(init_task.geoPointsArray, "La trobe");
mapView.getOverlays().add(itemizedOverlay );
MapController mc = mapView.getController();
mc.setCenter(new GeoPoint((int) (1E6 * -37.720754), (int) (1E6 * 145.048798))); // Some where .
mc.zoomToSpan(itemizedOverlay.getLatSpanE6(), itemizedOverlay.getLonSpanE6());
for (int i = 0; i < geoPointsArray.size() ; i++)
{
Log.d(" print points", " points " + geoPointsArray.get(i));
}*/
// Log.d(" print points", " Size " + init_task.geoPointsArray.size());
/*
mapView = (MapView) findViewById(R.id.mapview);
List<Overlay> mapOverlays = mapView.getOverlays();
//add any icon here for the marker
Drawable drawable = GoogleMapsAppActivity.this.getResources().getDrawable(R.drawable.poke);
MapViewItemizedOverlay itemizedOverlay = new MapViewItemizedOverlay(drawable,this);
//use your array here instead
//GeoPoint point1 = new GeoPoint(lat,lng);
OverlayItem overlayitem1 = new OverlayItem(point1, "Info", "You are here!" );
itemizedOverlay.addOverlay(overlayitem1);
mapOverlays.add(itemizedOverlay);
*/
}
private void initMap()
{
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
// mapView.setStreetView(true);
mc = mapView.getController();
}
public void theRouteDraw(GeoPoint p){
mc.animateTo(p);
mc.setZoom(13);
mapView.invalidate();
mapView.setSatellite(true);
}
private void initMyLocation() {
myLocOverlay = new MyLocationOverlay(this, mapView);
myLocOverlay.enableMyLocation();
mapView.getOverlays().add(new myLocOverlay());
}
#Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
class myLocOverlay extends Overlay{
public void draw(Canvas canvas, MapView mapv, boolean shadow){
super.draw(canvas, mapv, shadow);
Projection projection = mapView.getProjection();
Path p1 = new Path();
for (int i = 0; i < geoPointsArray.size(); i++) {
if (i == geoPointsArray.size() - 1) {
break;
}
Point from = new Point();
Point to = new Point();
projection.toPixels(geoPointsArray.get(i), from);
projection.toPixels(geoPointsArray.get(i + 1), to);
p1.moveTo(from.x, from.y);
p1.lineTo(to.x, to.y);
}
Paint mPaint = new Paint();
mPaint.setStyle(Style.STROKE);
mPaint.setColor(Color.BLACK);
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(4);
canvas.drawPath(p1, mPaint);
super.draw(canvas, mapView, shadow);
}
}
private class InitTask extends AsyncTask<String, GeoPoint, List<GeoPoint>> {
List<GeoPoint> geoPointsArray = new ArrayList<GeoPoint>();
GeoPoint p;
private ProgressDialog progressDialog;
private String rst = " " ;
private String[] strArr1;
private String[] strArr2;
protected void onPreExecute() {
//progress.show();
}
#Override
protected List<GeoPoint> doInBackground(String... arg0) {
String result = "";
int responseCode = 0;
int executeCount = 0;
HttpResponse response;
StringBuilder sb = new StringBuilder();
String line;
try
{
HttpClient client = new DefaultHttpClient();
HttpGet httppost = new HttpGet("http://xxxx/ccvo/mel-asset-data/query.php?lon="+ arg0[0].toString() + "&lat="+ arg0[1].toString() +"&within=" + arg0[2].toString() + "&keyword="+ arg0[3].toString().replace(" ", "%20"));
do
{
// progressDialog.setMessage("Passing paratmeters.. ("+(executeCount+1)+"/5)");
// Execute HTTP Post Request
executeCount++;
response = client.execute(httppost);
responseCode = response.getStatusLine().getStatusCode();
} while (executeCount < 5 && responseCode == 408);
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
while ((line = rd.readLine()) != null)
{
result = line.trim();
sb.append(line);
}
}catch (Exception e2) {
responseCode = 408;
e2.printStackTrace();
}
rst = result.toString();
// splits everything
if(rst != null && rst.length() > 0)
{
strArr1 = rst.split("\\|");
for(int i=0;i<strArr1.length;i++)
{
// Log.d("Results", "Array size1.1 " + i);
Log.v("Results", "Array split1.2 " + strArr1[i] );
if(strArr1[i] != null && strArr1[i].length() >0 && strArr1[i].contains(","))
{
strArr2 = strArr1[i].split(",");
for(int j=0; j<strArr2.length ;j++)
{
double y =0;
double x =0;
if(j == 1)
{
/// x
//Log.d("Results", "2If statem " + strArr2[j] );
x = Double.parseDouble(strArr2[j]);
y = Double.parseDouble(strArr2[j+1]);
geoPointsArray.add(new GeoPoint((int)(x*1e6), (int)(y*1e6)));
Log.d("geoPointsArray", "geoPointsArray " + geoPointsArray.toString() );
}
}
}
}
}
return geoPointsArray;
}
#Override
protected void onProgressUpdate(GeoPoint... progress1) {
theRouteDraw(progress1[0]);
geoPointsArray.add(progress1[0]);
int lon=progress1[0].getLongitudeE6();
int lat=progress1[0].getLatitudeE6();
GeoPoint p2=new GeoPoint(lon,lat);
geoPointsArray.add(p2);
initMyLocation();
}
#Override
protected void onPostExecute(List<GeoPoint> geoPointsArray)
{
//super.onPostExecute(geoPointsArray);
progress.dismiss();
//startActivity(i);
//i.getCharExtra("Geop", geoPointsArray);
Log.d("Lista", " check " + geoPointsArray.size());
// theRouteDraw(geoPointsArray);
}
}
}
My MirItemizedOverlay Class:
class MirItemizedOverlay extends ItemizedOverlay {
private List<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
public MirItemizedOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
// TODO Auto-generated constructor stub
}
#Override
protected OverlayItem createItem(int i) {
return mOverlays.get(i);
}
#Override
public int size() {
return mOverlays.size();
}
public void addOverlayItem(OverlayItem overlayItem) {
mOverlays.add(overlayItem);
populate();
}
#Override
public boolean onTouchEvent(MotionEvent event, MapView mapView)
{
//---when user lifts his finger---
if (event.getAction() == 1) {
GeoPoint p = mapView.getProjection().fromPixels(
(int) event.getX(),
(int) event.getY());
Toast.makeText(getBaseContext(),
p.getLatitudeE6() / 1E6 + "," +
p.getLongitudeE6() /1E6 ,
Toast.LENGTH_SHORT).show();
}
return false;
}
private Context getBaseContext() {
// TODO Auto-generated method stub
return null;
}
public void addOverlayItem(int lat, int lon, String title) {
GeoPoint point = new GeoPoint(lat, lon);
OverlayItem overlayItem = new OverlayItem(point, title, null);
addOverlayItem(overlayItem);
}
/* public void addOverlayItem(GeoPoint point , String title) {
OverlayItem overlayItem = new OverlayItem(point, title, null);
addOverlayItem(overlayItem);
//GeoPoint point = new GeoPoint(lat, lon);
}*/
}
The error :
: E/AndroidRuntime(2752): FATAL EXCEPTION: main
: E/AndroidRuntime(2752): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.phooogle/com.example.phooogle.GoogleMapsAppActivity}: java.lang.NullPointerException
: E/AndroidRuntime(2752): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
: E/AndroidRuntime(2752): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
: E/AndroidRuntime(2752): at android.app.ActivityThread.access$600(ActivityThread.java:130)
: E/AndroidRuntime(2752): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
: E/AndroidRuntime(2752): at android.os.Handler.dispatchMessage(Handler.java:99)
: E/AndroidRuntime(2752): at android.os.Looper.loop(Looper.java:137)
: E/AndroidRuntime(2752): at android.app.ActivityThread.main(ActivityThread.java:4745)
: E/AndroidRuntime(2752): at java.lang.reflect.Method.invokeNative(Native Method)
: E/AndroidRuntime(2752): at java.lang.reflect.Method.invoke(Method.java:511)
: E/AndroidRuntime(2752): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
: E/AndroidRuntime(2752): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
: E/AndroidRuntime(2752): at dalvik.system.NativeStart.main(Native Method)
: E/AndroidRuntime(2752): Caused by: java.lang.NullPointerException
: E/AndroidRuntime(2752): at com.example.phooogle.GoogleMapsAppActivity.onCreate(GoogleMapsAppActivity.java:68)
I've tried several ways to do like I tried to change the addOverlayItem method to accept the GeoPoitns from the AsyncTask return but also failed. I almost gave me on this. :)
Update
The problem resolved. Here is the fix:
try {
//String[] arrs = init_task.strArr2;
List<GeoPoint> geoL = init_task.get();
//Log.d(" Get the size " , " Geo List " + geoL.get(1).toString());
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
mc = mapView.getController();
List<Overlay> listOfOverlays = mapView.getOverlays();
Drawable drawable = this.getResources().getDrawable(R.drawable.poke);
MyItemizedOverlay itemizedoverlay = new MyItemizedOverlay(drawable, this);
for ( int i = 0; i < geoL.size() ; i++)
{
OverlayItem overlayitem1 = new OverlayItem(geoL.get(i), Selectedword + "s found! " , "It's withing " + selectedDistance + " To your position");
itemizedoverlay.addOverlay(overlayitem1);
listOfOverlays.add(itemizedoverlay);
}
//mc.animateTo(geoL.get(1));
mc.setCenter(new GeoPoint((int) (1E6 * gps.getLatitude() ), (int) (1E6 * gps.getLongitude() ))); // Some where .
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} finally {}
initMap();
initMyLocation();
// theRouteDraw();

Your issue is that mapView is null, you haven't called initMap() yet. This causes mapView.getOverlays().add(itemizedOverlay ); to fail.

How to put JSON lattitude and longitude on the map [duplicate]

This question already has an answer here:
Closed 10 years ago.
Possible Duplicate:
How to put JSON lOutput (latitude and longitude) on the map
I have a main activity which parses the JSON data from my mysql (table tracking:Lattitude and longitude) Now I want to pass this data in to my MapActivity and display on google maps. Any help is highly appreciated. Thanks!
this my JSONactivity
public class JSONActivity extends Activity{
private JSONObject jObject;
private String xResult ="";
//Seusuaikan url dengan nama domain
private String url = "http://10.0.2.2/labiltrack/daftartracking.php";
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.daftartrack);
TextView txtResult = (TextView)findViewById(R.id.TextViewResult);
//url += "?lattitude=" + UserData.getEmail();
xResult = getRequest(url);
try {
parse(txtResult);
} catch (Exception e) {
e.printStackTrace();
}
}
private void parse(TextView txtResult) throws Exception {
// TODO Auto-generated method stub
jObject = new JSONObject(xResult);
JSONArray menuitemArray = jObject.getJSONArray("joel");
String sret="";
//int j = 0;
for (int i = 0; i < menuitemArray.length(); i++) {
sret +=menuitemArray.getJSONObject(i).
getString("lattitude").toString()+" : ";
System.out.println(menuitemArray.getJSONObject(i)
.getString("lattitude").toString());
System.out.println(menuitemArray.getJSONObject(i).getString(
"longitude").toString());
sret +=menuitemArray.getJSONObject(i).getString(
"lattitude").toString()+"\n";
//j=i;
}txtResult.setText(sret);
}
/**
* Method untuk Mengirimkan data keserver
* event by button login diklik
*
* #param view
*/
private String getRequest(String url) {
// TODO Auto-generated method stub
String sret="";
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(url);
try{
HttpResponse response = client.execute(request);
sret =request(response);
}catch(Exception ex){
Toast.makeText(this,"jo "+sret, Toast.LENGTH_SHORT).show();
}
return sret;
}
/**
* Method untuk Menenrima data dari server
* #param response
* #return
*/
private String request(HttpResponse response) {
// TODO Auto-generated method stub
String result = "";
try{
InputStream in = response.getEntity().getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder str = new StringBuilder();
String line = null;
while((line = reader.readLine()) != null){
str.append(line + "\n");
}
in.close();
result = str.toString();
}catch(Exception ex){
result = "Error";
}
return result;
}
}
and this my mapActivity
public class mapactivity extends MapActivity {
private MapView mapView;
MapController mc;
GeoPoint p;
//private MyLocationOverlay me = null;
class MapOverlays extends com.google.android.maps.Overlay
{
#Override
public boolean draw (Canvas canvas, MapView mapView, boolean shadow, long when)
{
super.draw(canvas, mapView, shadow);
//translate the geopoint to screen pixels
Point screenPts = new Point();
mapView.getProjection().toPixels(p, screenPts);
//tambah marker
Bitmap bmp = BitmapFactory.decodeResource(getResources (), R.drawable.pin_red);
canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);
//mapView.setSatellite(true);
return true;
}
#Override
public boolean onTouchEvent(MotionEvent event, MapView mapView)
{
//---when user lifts his finger---
if (event.getAction() == 1) {
GeoPoint p = mapView.getProjection().fromPixels(
(int) event.getX(),
(int) event.getY());
Toast.makeText(getBaseContext(),
p.getLatitudeE6() / 1E6 + "," +
p.getLongitudeE6() /1E6 ,
Toast.LENGTH_SHORT).show();
mc.animateTo(p);
//geocoding
Geocoder geoCoder = new Geocoder(
getBaseContext(), Locale.getDefault());
try {
List<Address> addresses = geoCoder.getFromLocation(
p.getLatitudeE6() / 1E6,
p.getLongitudeE6() / 1E6, 1);
String add = "";
if (addresses.size() > 0)
{
for (int i=0; i<addresses.get(0).getMaxAddressLineIndex();
i++)
add += addresses.get(0).getAddressLine(i) + "\n";
}
Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show();
}
catch (IOException e) {
e.printStackTrace();
}
return true;
}
else
return false;
} }
/** Called when the activity is first created. */
#SuppressWarnings("deprecation")
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mapview1);
//utk mnampilkan zoom
mapView = (MapView) findViewById(R.id.mapView);
LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);
View zoomView = mapView.getZoomControls();
zoomLayout.addView(zoomView,
new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
mapView.displayZoomControls(true);
//menampilkan default peta banda aceh
mc = mapView.getController();
String coordinates[] = {"5.550381", "95.318699"};
double lat = Double.parseDouble(coordinates[0]);
double lng = Double.parseDouble(coordinates[1]);
p = new GeoPoint(
(int) (lat * 1E6),
(int) (lng * 1E6));
mc.animateTo(p);
mc.setZoom(14);
mapView.invalidate();
//tambah marker
MapOverlays mapOverlay = new MapOverlays();
List<Overlay> listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);
mapView.invalidate();
}
public void btnSatelitClick(View v){
mapView.setSatellite(true);
mapView.setStreetView(false);
}
public void btnjalanClick (View v){
mapView.setSatellite(false);
mapView.setStreetView(true);
}
protected boolean isRouteDisplayed()
{
//auto generate method
return false;
}
}

as you have only to variable to pass so use intent and pass the data ......and i think you have rest of code writen
put in the JSONActivity from where you want to open mapActivity and you alos have the variable latitude and longitude with their values
Intent i= new Intent(getApplicationContext(), mapActivity.class);
i.putExtra("lattitude",lattitude);
i.putExtra("longitude",longitude);
startActivity(i);
Then in the new activity mapActivity, retrieve those values:
inplace of this put String coordinates[] = {"5.550381", "95.318699"};
Bundle extras = getIntent().getExtras();
if(extras !=null) {
String lattitude= extras.getString("lattitude");
String longitude= extras.getString("longitude");
double lat = Double.parseDouble(lattitude);
double lng = Double.parseDouble(longitude);
}