Develop Reference

MapView display route between a lot of GeoPoints

I have an app where an user is given a lot of points (100 or even more) and he has to physically go to those points and "check in". They have to go to those points in a certain order, so I need to display a route in the MapView which passes through all those points.
I've read a lot about getting the route between two points, but I can't find anything about drawing a complex route with a lot of points. Is this behavior possible?

public class RouteOverlay extends Overlay {
private GeoPoint gp1;
private GeoPoint gp2;
private int color;
public RouteOverlay(GeoPoint gp1, GeoPoint gp2, int color) {
this.gp1 = gp1;
this.gp2 = gp2;
this.color = color;
}
Now all that's left now for our Overlay is to override the draw() method and draw the line as we need it:
#Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
Projection projection = mapView.getProjection();
Paint paint = new Paint();
Point point = new Point();
projection.toPixels(gp1, point);
paint.setColor(color);
Point point2 = new Point();
projection.toPixels(gp2, point2);
paint.setStrokeWidth(5);
paint.setAlpha(120);
canvas.drawLine(point.x, point.y, point2.x, point2.y, paint);
super.draw(canvas, mapView, shadow);
}
Back in the Activity, just iterate over the GeoPoints that you got from google maps and add each of them to the MapView:
private void drawPath(List geoPoints, int color) {
List overlays = mapView.getOverlays();
for (int i = 1; i < geoPoints.size(); i++) {
overlays.add(new RouteOverlay(geoPoints.get(i - 1), geoPoints.get(i), color));
}
}

Try something like this
if(DataSources.ActivitiesList.length >0)
{
String address = "http://maps.google.com/maps?daddr=" + DataSources.ActivitiesList[0].SiteLatitude.toString() + "," + DataSources.ActivitiesList[0].SiteLongitude.toString();
for (int i= 1 ;i < DataSources.ActivitiesList.length ; i++)
{
if(DataSources.ActivitiesList[i].SiteLatitude != null)
address += "+to:" + DataSources.ActivitiesList[i].SiteLatitude + "," + DataSources.ActivitiesList[i].SiteLongitude;
}
Intent intent = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse(address));
startActivity(intent);
break;
}

plot a route on google maps, android

I want to draw a route on google map with the change in my position using GPS. As my location changes(when new geopoints are created), the dot moves on the google map but i'm unable to draw the line on the map.
Please help in plotting the route on google maps. Below is my code
`
LocationManager locman;
LocationListener loclis;
Location location;
private MapView map;
List<GeoPoint> geoPointsArray = new ArrayList<GeoPoint>();
private MapController controller;
String provider = LocationManager.GPS_PROVIDER;
double lat;
double lon;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initMapView();
initMyLocation();
locman = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
//locman.requestLocationUpdates(provider,60000, 100,loclis);
//Location = locman.getLastKnownLocation(provider);
}
/** Find and initialize the map view. */
private void initMapView() {
map = (MapView) findViewById(R.id.mapView);
controller = map.getController();
map.setSatellite(false);
map.setBuiltInZoomControls(true);
}
/** Find Current Position on Map. */
private void initMyLocation() {
final MyLocationOverlay overlay = new MyLocationOverlay(this, map);
overlay.enableMyLocation();
overlay.enableCompass(); // does not work in emulator
overlay.runOnFirstFix(new Runnable() {
public void run() {
// Zoom in to current location
controller.setZoom(16);
controller.animateTo(overlay.getMyLocation());
}
});
map.getOverlays().add(overlay);
}
public void onLocationChanged(Location location) {
if (location != null){
lat = location.getLatitude();
lon = location.getLongitude();
GeoPoint New_geopoint = new GeoPoint((int)(lat*1e6),(int)(lon*1e6));
controller.animateTo(New_geopoint);
}
}
class MyOverlay extends Overlay{
public MyOverlay(){
}
public void draw(Canvas canvas, MapView mapv, boolean shadow){
super.draw(canvas, mapv, shadow);
Paint paint;
paint = new Paint();
paint.setColor(Color.GREEN);
paint.setAntiAlias(true);
paint.setStyle(Style.STROKE);
paint.setStrokeWidth(3);
Projection projection = map.getProjection();
Path p = 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);
p.moveTo(from.x, from.y);
canvas.drawLine(from.x, from.y, to.x, to.y, paint);
}
}
}
`

Wrong distances when creating random locations

I am trying to create random locations nearby my location. What i want is to create random latitude/longitude pairs inside a 200 meters circle surrounding my location. After asking this question: generate random locations nearby my location this is what i have come up with.
in onLocationChanged, this is what i do:
private void updateWithNewLocation(Location location) {
if (location != null) {
this.myItemizedOverlay.clear();
this.nonPlayerItemizedOverlay.clear();
this.mapOverlays.clear();
// Update my map location.
Double latitude = location.getLatitude() * 1E6;
Double longitude = location.getLongitude() * 1E6;
GeoPoint geoPoint = new GeoPoint(latitude.intValue(),
longitude.intValue());
CustomOverlayItem pcOverlayItem = new CustomOverlayItem(geoPoint,
"", "", "");
this.mapController.animateTo(geoPoint);
this.myItemizedOverlay.setLocation(location);
this.myItemizedOverlay.addOverlay(pcOverlayItem);
this.mapOverlays.add(this.myItemizedOverlay);
// Everytime i get a new location i generate random non player
// characters near my location
int numberOfNonPlayers = new Random().nextInt(5);
for (int i = 0; i < numberOfNonPlayers; i++) {
int radius = (int) this.myMapView.getProjection()
.metersToEquatorPixels(200);
double lowerLimit = -1;
double upperLimit = 1;
Double newLatitude = location.getLatitude()
* 1E6
+ (radius * (lowerLimit + (Math.random() * ((upperLimit - lowerLimit) + 1))));
Double newLongitude = location.getLongitude()
* 1E6
+ (radius * (lowerLimit + (Math.random() * ((upperLimit - lowerLimit) + 1))));
GeoPoint geoPoint2 = new GeoPoint(newLatitude.intValue(),
newLongitude.intValue());
CustomOverlayItem npcOverlayItem = new CustomOverlayItem(
geoPoint2, "", "", "");
Location newLocation = new Location("npc " + i);
newLocation.setLatitude(newLatitude);
newLocation.setLongitude(newLongitude);
this.nonPlayerItemizedOverlay = new NonPlayerItemizedOverlay(
this.nonPlayerDrawable, this.myMapView);
this.nonPlayerItemizedOverlay.setLocation(newLocation);
this.nonPlayerItemizedOverlay.addOverlay(npcOverlayItem);
this.mapOverlays.add(this.nonPlayerItemizedOverlay);
}
}
}
And this is my NonPlayerItemizedOverlay class:
public class NonPlayerItemizedOverlay extends BaseItemizedOverlay {
public NonPlayerItemizedOverlay(Drawable defaultMarker, MapView mapView) {
super(defaultMarker, mapView);
// TODO Auto-generated constructor stub
}
private Location location;
public static int metersToRadius(float meters, MapView map, double latitude) {
return (int) (map.getProjection().metersToEquatorPixels(meters) * (1 / Math
.cos(Math.toRadians(latitude))));
}
#Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
super.draw(canvas, mapView, shadow);
if (shadow == false) {
Projection projection = mapView.getProjection();
// Get the current location
Double latitude = location.getLatitude();
Double longitude = location.getLongitude();
GeoPoint geoPoint = new GeoPoint(latitude.intValue(),
longitude.intValue());
// Convert the location to screen pixels
Point point = new Point();
projection.toPixels(geoPoint, point);
// int radius = metersToRadius(30, mapView, latitude);
int radius = (int) mapView.getProjection()
.metersToEquatorPixels(50);
RectF oval = new RectF(point.x - radius, point.y - radius, point.x
+ radius, point.y + radius);
// Setup the paint
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setStrokeWidth(2.0f);
paint.setColor(0xffE62020);
paint.setStyle(Style.STROKE);
canvas.drawOval(oval, paint);
paint.setColor(0x18E62020);
paint.setStyle(Style.FILL);
canvas.drawOval(oval, paint);
}
}
public Location getLocation() {
return location;
}
public void setLocation(Location location) {
this.location = location;
}
And my MyItemizedOverlay class:
public class MyItemizedOverlay extends BaseItemizedOverlay {
public MyItemizedOverlay(Drawable defaultMarker, MapView mapView) {
super(defaultMarker, mapView);
// TODO Auto-generated constructor stub
}
private Location location;
public static int metersToRadius(float meters, MapView map, double latitude) {
return (int) (map.getProjection().metersToEquatorPixels(meters) * (1 / Math
.cos(Math.toRadians(latitude))));
}
#Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
super.draw(canvas, mapView, shadow);
if (shadow == false) {
Projection projection = mapView.getProjection();
// Get the current location
Double latitude = location.getLatitude() * 1E6;
Double longitude = location.getLongitude() * 1E6;
GeoPoint geoPoint = new GeoPoint(latitude.intValue(),
longitude.intValue());
// Convert the location to screen pixels
Point point = new Point();
projection.toPixels(geoPoint, point);
// int radius = metersToRadius(100, mapView, latitude);
int radius = (int) mapView.getProjection().metersToEquatorPixels(
200);
RectF oval = new RectF(point.x - radius, point.y - radius, point.x
+ radius, point.y + radius);
// Setup the paint
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setStrokeWidth(2.0f);
paint.setColor(0xff6666ff);
paint.setStyle(Style.STROKE);
canvas.drawOval(oval, paint);
paint.setColor(0x186666ff);
paint.setStyle(Style.FILL);
canvas.drawOval(oval, paint);
}
}
public Location getLocation() {
return location;
}
public void setLocation(Location location) {
this.location = location;
}
The thing is that something weird is happening because all the random locations are too near of my location center, it seems that the formula does not cover the whole radius and i think that distances are not in real meters.
Any idea of what could be wrong with my formula?
Thanks in advance

For questions regarding map projections and coordinate calculations, this SE site could be helpful: http://gis.stackexchange.com (Geographic Information Systems).

To be sure use the distanceTo() formula of location class.You can do it this way:
double distance = a.distanceTo(b);
where a and b are Location objects.

How do you draw a line from previous point to current point in Android Google Maps?

I am trying to create a GPS tracking app, and is stuck on how I can draw a line from the previous point to current point. I've tried using an Overlay, but it does not display... I am not THAT good on Java, so please speak to me like I'm 4 years old...
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initMapView();
initMyLocation();
TabHost.TabSpec spec;
TabHost th = (TabHost)findViewById(R.id.tabhost);
th.setup();
spec = th.newTabSpec("tag1");
spec.setContent(R.id.mapTab);
spec.setIndicator("Map");
th.addTab(spec);
spec = th.newTabSpec("tag2");
spec.setContent(R.id.logTab);
spec.setIndicator("Log");
th.addTab(spec);
spec = th.newTabSpec("tag3");
spec.setContent(R.id.detailsTab);
spec.setIndicator("Details");
th.addTab(spec);
}
#Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
//Map and Controls
private void initMapView() {
map = (MapView) findViewById(R.id.mvMain);
controller = map.getController();
map.setSatellite(true);
//map.setStreetView(true);
map.setBuiltInZoomControls(true);
}
//Creates an Overlay that marks current position
private void initMyLocation() {
final MyLocationOverlay overlay = new MyLocationOverlay(this, map);
overlay.enableMyLocation();
overlay.enableCompass();
overlay.runOnFirstFix(new Runnable() {
public void run() {
controller.setZoom(17);
controller.animateTo(overlay.getMyLocation());
map.getOverlays().add(overlay);
}
});
}
//Experiment
public class detailsTab extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.id.detailsTab);
LocationManager locationManager;
String context = Context.LOCATION_SERVICE;
locationManager = (LocationManager)getSystemService(context);
String provider = LocationManager.GPS_PROVIDER;
Location location = locationManager.getLastKnownLocation(provider);
updateWithNewLocation(location);
}
private void updateWithNewLocation(Location location) {
String latLongString;
TextView myLocationText;
myLocationText = (TextView)findViewById(R.id.detailsText);
if(location != null){
double lat = location.getLatitude();
double lng = location.getLongitude();
latLongString = "Lat:" + lat + "\nLong" + lng;
}
else {
latLongString = "No Location Found";
}
myLocationText.setText("Your current position is: \n" + latLongString);
}
}
public class NewOverlay extends Overlay {
#Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
Projection projection = mapView.getProjection();
Double lat = lati *1E6;
Double lng = longi *1E6;
GeoPoint geoPoint = new GeoPoint(lat.intValue(), lng.intValue());
if (shadow == false) {
Point myPoint = new Point();
projection.toPixels(geoPoint, myPoint);
//Creating and setting up the paint brush
Paint paint = new Paint();
paint.setARGB(250, 255, 0, 0);
paint.setAntiAlias(true);
paint.setFakeBoldText(true);
//Create circle
int rad = 25;
RectF oval = new RectF(myPoint.x-rad, myPoint.y-rad, myPoint.x+rad, myPoint.y+rad);
canvas.drawOval(oval, paint);
canvas.drawText("Red Circle", myPoint.x+rad, myPoint.y, paint);
}
}
}
}

I do that this way, inside draw() method,
int x1 = -1, y1 = -1, x2 = -1, y2 = -1;
Paint paint = new Paint();
paint.setColor(Color.rgb(0x7b, 0x7b, 0xff));
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(5);
if(mPoints!=null || mPoints.size()<2)
{
for (int i = 0; i < mPoints.size(); i++) {
Point point = new Point();
mv.getProjection().toPixels(mPoints.get(i), point);
Point loc = new Point();
mv.getProjection().toPixels(new GeoPoint((int) (location.getLatitude()*1.0E6),(int) (location.getLongitude()*1.0E6)), loc);
x2 = point.x;
y2 = point.y;
if (i == 0)
{
x2 = loc.x;
y2 = loc.y;
}
if (i > 0) {
canvas.drawLine(x1, y1, x2, y2, paint);
}
x1 = x2;
y1 = y2;
}
}
This code will draw for me a whole route, mPoints is an array of GeoPoint that I want to draw them. This should be useful for you.

public void draw(Canvas canvas, MapView mapv, boolean shadow){
super.draw(canvas, mapv, shadow);
Projection projection = mapv.getProjection();
Path p = 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);
p.moveTo(from.x, from.y);
p.lineTo(to.x, to.y);
}
Paint mPaint = new Paint();
mPaint.setStyle(Style.STROKE);
mPaint.setColor(Color.GREEN);
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(5);
canvas.drawPath(p, mPaint);
mapv.invalidate();
super.draw(canvas, mapv, shadow);
}//draw()
we can use the above method to draw route as we move place to place. where geoPointsArray is array of locations received. And in your onCreate() you need to call mapv.invalidate(); to draw route continously

Can't get geopoint when using class MyLocationOverlay

I can't marker current location... Apps always get messeger "Cannot determine location".
I run app on Samsung galaxy mini and i was turn on GPS :(
Class FixedMyLocationOverlay
public class FixedMyLocationOverlay extends MyLocationOverlay {
private boolean bugged = false;
private Drawable drawable;
private Paint accuracyPaint;
private Point center;
private Point left;
private int width;
private int height;
public FixedMyLocationOverlay(Context context, MapView mapView) {
super(context, mapView);
}
#Override
protected void drawMyLocation(Canvas canvas, MapView mapView,
Location lastFix, GeoPoint myLocation, long when) {
if(!bugged) {
try {
super.drawMyLocation(canvas, mapView, lastFix, myLocation, when);
} catch (Exception e) {
// we found a buggy phone, draw the location icons ourselves
bugged = true;
}
}
if(bugged) {
if(drawable == null) {
accuracyPaint = new Paint();
accuracyPaint.setAntiAlias(true);
accuracyPaint.setStrokeWidth(2.0f);
drawable = mapView.getContext().getResources().getDrawable(R.drawable.here);
width = drawable.getIntrinsicWidth();
height = drawable.getIntrinsicHeight();
center = new Point();
left = new Point();
}
Projection projection = mapView.getProjection();
double latitude = lastFix.getLatitude();
double longitude = lastFix.getLongitude();
float accuracy = lastFix.getAccuracy();
float[] result = new float[1];
Location.distanceBetween(latitude, longitude, latitude, longitude + 1, result);
float longitudeLineDistance = result[0];
GeoPoint leftGeo = new GeoPoint((int)(latitude*1e6), (int)((longitude-accuracy/longitudeLineDistance)*1e6));
projection.toPixels(leftGeo, left);
projection.toPixels(myLocation, center);
int radius = center.x - left.x;
accuracyPaint.setColor(0xff6666ff);
accuracyPaint.setStyle(Style.STROKE);
canvas.drawCircle(center.x, center.y, radius, accuracyPaint);
accuracyPaint.setColor(0x186666ff);
accuracyPaint.setStyle(Style.FILL);
canvas.drawCircle(center.x, center.y, radius, accuracyPaint);
drawable.setBounds(center.x - width/2, center.y - height/2, center.x + width/2, center.y + height/2);
drawable.draw(canvas);
}
}
}
Code Activity
public class atm_atmogan extends MapActivity {
private MapView mapView;
private MyLocationOverlay myLocationOverlay;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.atm_atmogan);
mapView = (MapView) findViewById(R.id.map_view);
mapView.setBuiltInZoomControls(true);
myLocationOverlay = new FixedMyLocationOverlay(this, mapView);
mapView.getOverlays().add(myLocationOverlay);
mapView.postInvalidate();
zoomToMyLocation();
}
#Override
protected void onResume() {
super.onResume();
myLocationOverlay.enableMyLocation();
}
#Override
protected void onPause() {
super.onPause();
myLocationOverlay.disableMyLocation();
}
private void zoomToMyLocation() {
GeoPoint myLocationGeoPoint = myLocationOverlay.getMyLocation();
if(myLocationGeoPoint != null) {
mapView.getController().animateTo(myLocationGeoPoint);
mapView.getController().setZoom(18);
}
else {
Toast.makeText(this, "Cannot determine location", Toast.LENGTH_SHORT).show();
}
}
#Override
protected boolean isRouteDisplayed() {
return false;
}
}

You will need to get your actual location using the location Manager class/interface.
This tutorial will cover everything you need to know about that http://www.vogella.de/articles/AndroidLocationAPI/article.html
hope this helps