I am using google map V2. I want to use geocoderto find the location but getFromLocationName() it is returning me null value and I couldn't find why. Just see my code and suggest me, what should I do?
EditText sLocation = (EditText) v.findViewById(R.id.editText1);
String location = sLocation.getText().toString();
List<android.location.Address> addressList= null;
if (location != null || !location.equals("")) {
Geocoder geocoder = new Geocoder(getActivity().getApplicationContext());
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
android.location.Address address = addressList.get(0);
LatLng latlng = new LatLng(address.getLatitude(), address.getLatitude());
gMap.addMarker(new MarkerOptions().position(latlng).title("Marker"));
gMap.animateCamera(CameraUpdateFactory.newLatLng(latlng));
}
I was getting null value form getFromLocationName(). Because, my addressList was getting "null" value from location. When I declared my EditText in onClick method then getFromLocationName() return me correct value like this:
sButton =(Button) v.findViewById(R.id.generalId);
sButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
EditText sLocation = (EditText)getActivity().findViewById(R.id.editText1);
location = sLocation.getText().toString();
List<android.location.Address> addressList= null;
if (location != null || location.length()>0) {
Geocoder geocoder = new Geocoder(getActivity().getApplicationContext());
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
android.location.Address address = addressList.get(0);
String locality = address.getLocality();
Toast.makeText(getActivity(), locality, Toast.LENGTH_LONG).show();
double latitude = address.getLatitude();
double longitude = address.getLongitude();
LatLng latLng = new LatLng(latitude, longitude);
gMap.addMarker(new MarkerOptions().position(latLng).title("Marker"));
gMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
}
}
});
Related
Hello i am creating App for iOS and Android. The issue i want to fix that on the load on page i want to display the map with the address. I can get Lat Long successfully but i cannot getting address that i want to display on a label. Below is my code that i am using.
using Plugin.Geolocator;
using Xamarin.Forms.Maps;
private Position _position;
// Map map;
double Lat, Long;
string address = "";
public TestPage()
{
NavigationPage.SetHasNavigationBar(this, false);
InitializeComponent();
GetPosition();
if (_position != null)
{
Lat = _position.Latitude;
Long = _position.Longitude;
}
//Task<String> str = GetAddress();
map.MoveToRegion(MapSpan.FromCenterAndRadius(new Position(Lat, Long), Distance.FromMiles(1)));
var position = new Position(Lat, Long);
var pin = new Pin
{
Type = PinType.Place,
Position = position,
Label = ""
};
map.Pins.Add(pin);
var zoomLevel = 17.83;
var latlongdegrees = 360 / (Math.Pow(2, zoomLevel));
map.MoveToRegion(new MapSpan(position, latlongdegrees, latlongdegrees));
LabelTime.Text = DateTime.Now.ToString("hh:mm tt") + " " + DateTime.Now.ToString("MM/dd/yyyy");
string recentAddress = address; // trying to get adderss for location
}
GetPosition()
public async void GetPosition()
{
Plugin.Geolocator.Abstractions.Position position = null;
try
{
var locator = CrossGeolocator.Current;
locator.DesiredAccuracy = 100.0;
position = await locator.GetLastKnownLocationAsync();
if (position != null)
{
_position = new Position(position.Latitude, position.Longitude);
//got a cahched position, so let's use it.
return;
}
if (!locator.IsGeolocationAvailable || !locator.IsGeolocationEnabled)
{
//not available or enabled
return;
}
position = await locator.GetPositionAsync(TimeSpan.FromSeconds(10), null, true);
}
catch (Exception ex)
{
// error(ex.Message, Convert.ToString(ex.InnerException), ex.Source, ex.StackTrace);
}
_position = new Position(position.Latitude, position.Longitude);
if (position == null)
return;
}
GetAddress()
public async Task<String> GetAddress()
{
// string Addrsss = "";
try
{
Geocoder geoCoder = new Geocoder();
if (_position != null)
{
var possibleAddresses = await geoCoder.GetAddressesForPositionAsync(_position);
await Task.Delay(2000);
foreach (var a in possibleAddresses)
{
address += a + "\n";
}
}
return address;
}
catch (Exception ex)
{
throw;
}
}
I also try to get the current address on OnAppearing()
protected override void OnAppearing()
{
this.Appearing += TestPage_Appearing; //Subscribe to event
base.OnAppearing();
}
protected async void TestPage_Appearing(object sender, EventArgs args)
{
GetPosition();
address= await GetAddress();
string a = address;
this.Appearing -= TestPage_Appearing; //Unsubscribe
}
You can get placemark address using Xamarin.Essentials as below,
protected async override void OnAppearing()
{
await GetAddress();
}
private async Task GetAddress()
{
var lat = 47.673988;
var lon = -122.121513;
var placemarks = await Geocoding.GetPlacemarksAsync(lat, lon);
var placemark = placemarks?.FirstOrDefault();
if (placemark != null)
{
var geocodeAddress =
$"AdminArea: {placemark.AdminArea}\n" +
$"CountryCode: {placemark.CountryCode}\n" +
$"CountryName: {placemark.CountryName}\n" +
$"FeatureName: {placemark.FeatureName}\n" +
$"Locality: {placemark.Locality}\n" +
$"PostalCode: {placemark.PostalCode}\n" +
$"SubAdminArea: {placemark.SubAdminArea}\n" +
$"SubLocality: {placemark.SubLocality}\n" +
$"SubThoroughfare: {placemark.SubThoroughfare}\n" +
$"Thoroughfare: {placemark.Thoroughfare}\n";
Console.WriteLine(geocodeAddress);
}
}
refer this link for in depth details
Also this one for detailed implementation
I'm using Xamarin.forms.Maps and ExtendedMap, I did make a custom control, here I can get the location when the user tap on map but by default the map position is in the middle of the occean, something like this 0.0756931, 0.0786793. I was seaching and trying for a while but I did not find the solution.
I did see that the map is loading the region.LatitudeDegrees and region.LongitudeDegrees but I really don't why is this happen.
Xamarin.Forms 3.0.0.482510
Xamarin.Forms.Maps 3.0.0.482510
Xamarin.Plugin.ExternalMaps 4.0.1
MapGoogleView.xaml
<local:ExtendedMap
WidthRequest="320" HeightRequest="200"
x:Name="MyMap" Tap="OnTap"
IsShowingUser="true"
MapType="Street"/>
MapGoogleView.xaml.cs
public MapGoogleView(double lat, double lon)
{
InitializeComponent();
NavigationPage.SetHasNavigationBar(this, false);
var map = new ExtendedMap(
MapSpan.FromCenterAndRadius(
new Position(lat, lon), Distance.FromMiles(0.3)))
{
IsShowingUser = true,
HeightRequest = 100,
WidthRequest = 900,
VerticalOptions = LayoutOptions.FillAndExpand,
MapType = MapType.Street
};
var stack = new StackLayout { Spacing = 0 };
stack.Children.Add(map);
Content = stack;
var position = new Position(lat, lon); // Latitude, Longitude
var pin = new Pin
{
Type = PinType.Generic,
Position = position,
Label = "Ubicación",
Address = "Latitud: " + lat.ToString() + ", Longitud: " + lon.ToString(),
};
MyMap.Pins.Add(pin);
map.MoveToRegion(
MapSpan.FromCenterAndRadius(
new Position(lat, lon), Distance.FromMiles(1)));
}
ExtendedMap.cs
public class ExtendedMap : Map
{
public event EventHandler<TapEventArgs> Tap;
public ExtendedMap()
{
}
public ExtendedMap(MapSpan region) : base(region)
{
}
public void OnTap(Position coordinate)
{
OnTap(new TapEventArgs { Position = coordinate });
}
public async void OnTap(Position coordinate)
{
try
{
OnTap(new TapEventArgs { Position = coordinate });
}
catch (Exception error)
{
await Application.Current.MainPage.DisplayAlert(
"Error",
error.Message,
"Aceptar");
return;
}
}
protected virtual void OnTap(TapEventArgs e)
{
var handler = Tap;
if (handler != null) handler(this, e);
}
}
public class TapEventArgs : EventArgs
{
public Position Position { get; set; }
}
}
Droid
ExtendedMapRenderer.cs
public class ExtendedMapRenderer : MapRenderer, IOnMapReadyCallback
{
private GoogleMap _map;
public void OnMapReady(GoogleMap googleMap)
{
_map = googleMap;
if (_map != null)
//_map.GestureRecognizer.Add(new);
_map.MapClick += googleMap_MapClick;
}
public ExtendedMapRenderer()
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Map> e) //cambiar a xamarin.forms.view
{
if (_map != null)
_map.MapClick -= googleMap_MapClick;
base.OnElementChanged(e);
if (Control != null)
((MapView)Control).GetMapAsync(this);
}
private void googleMap_MapClick(object sender, GoogleMap.MapClickEventArgs e)
{
((ExtendedMap)Element).OnTap(new Position(e.Point.Latitude, e.Point.Longitude));
}
}
If you're struggling to obtain the Latitude and Longitude coordinates using the plugins described above, you could obtain your devices lon/lat by doing the following:
Download and install into your application the Geolocator Plugin. Made by the man the myth the legend James Montemagno.
Following that, you can follow this guide to obtain your devices longitude and latitude coordinates.
On doing that you can assign your global lat and lon variables to the values retrieved using that plugin. I don't know if you did this prior to instantiating your maps or have used a different method but this is how I get my devices Lat & Lon.
As a fallback if a device has location disabled or does not have the ability to retrieve its GPS data I always set my default lat & lon to the capital city of the devices country region.
RegionInfo.CurrentRegion
then if UK set the lat & lon to london city center for example.
Since a long time, I'm trying to make work a polyline for crossplateform using.
I did it and it works well, I followed the Map Control tutorial in first, and then Highlight a Route on a Map tutorial.
I then update the code to make it reloads if a any changes comes, however, I'm getting an issue and I couldn't figure it out... It does works for Android & iOS.
polyline.Path = new Geopath(coordinates); throws Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))
The problem is that my two others renderer (Android & iOS) works.. Maybe something isn't possible because I work with WinPhone8.1 unlike the tutorial, which is UWP.
public class CustomMapRenderer : MapRenderer
{
MapControl nativeMap;
CustomMap formsMap;
protected override void OnElementChanged(ElementChangedEventArgs<Map> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
nativeMap = Control as MapControl;
}
if (e.NewElement != null)
{
formsMap = (CustomMap)e.NewElement;
nativeMap = Control as MapControl;
UpdatePolyLine();
}
}
protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (this.Element == null || this.Control == null)
return;
if (e.PropertyName == CustomMap.RouteCoordinatesProperty.PropertyName)
{
UpdatePolyLine();
}
}
private void UpdatePolyLine()
{
if (nativeMap != null)
{
var coordinates = new List<BasicGeoposition>();
foreach (var position in formsMap.RouteCoordinates)
{
coordinates.Add(new BasicGeoposition() { Latitude = position.Latitude, Longitude = position.Longitude });
}
var polyline = new MapPolyline();
polyline.StrokeColor = Color.FromArgb(128, 255, 0, 0);
polyline.StrokeThickness = 5;
polyline.Path = new Geopath(coordinates);
nativeMap.MapElements.Add(polyline);
}
}
}
I also read that a key is needed, so maybe I doesn't use this key in a good way.. I tried with UWP Public Key and WinPhone8.X and earlier Key, but without success too..
Does someone has an idea? This part a really big problem in my app..
Thank in advance !
After a long time, I found why it didn't works...
If you're doing like me, if you do a HttpRequest to something as Google Direction API, then the result will comes after the first passage in the OnElementChanged().
Because formsMap.RouteCoordinates isn't null but empty, the Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED)) is thrown..
This is the good CustomMapRenderer for PolyLine use
using PROJECT;
using PROJECT.UWP;
using System.Collections.Generic;
using Windows.Devices.Geolocation;
using Windows.UI.Xaml.Controls.Maps;
using Xamarin.Forms.Maps;
using Xamarin.Forms.Maps.UWP;
using Xamarin.Forms.Platform.UWP;
[assembly: ExportRenderer(typeof(CustomMap), typeof(CustomMapRenderer))]
namespace PROJECT.UWP
{
public class CustomMapRenderer : MapRenderer
{
MapControl nativeMap;
CustomMap formsMap;
protected override void OnElementChanged(ElementChangedEventArgs<Map> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
nativeMap = Control as MapControl;
}
if (e.NewElement != null)
{
formsMap = (CustomMap)e.NewElement;
nativeMap = Control as MapControl;
UpdatePolyLine();
}
}
protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (this.Element == null || this.Control == null)
return;
if (e.PropertyName == CustomMap.RouteCoordinatesProperty.PropertyName)
{
UpdatePolyLine();
}
}
private void UpdatePolyLine()
{
if (formsMap != null && formsMap.RouteCoordinates.Count > 0)
{
List<BasicGeoposition> coordinates = new List<BasicGeoposition>();
foreach (var position in formsMap.RouteCoordinates)
{
coordinates.Add(new BasicGeoposition() { Latitude = position.Latitude, Longitude = position.Longitude });
}
Geopath path = new Geopath(coordinates);
MapPolyline polyline = new MapPolyline();
polyline.StrokeColor = Windows.UI.Color.FromArgb(128, 255, 0, 0);
polyline.StrokeThickness = 5;
polyline.Path = path;
nativeMap.MapElements.Add(polyline);
}
}
}
}
I've got an app that tracks vehicles and draws a polyline of their travel path on a map. I want to convert this polyline into a route using the directions service routing. This will allow me to be able to drag the path around and manipulate it etc.
The problem is I can't think of a nice solution to this, and I'm not sure if it's possible. If I pass in the array of coordinates of the polyline to the directions service route it only draws a route using the start and the end of the polyline, it doesn't take into consideration any of the coordinates in between.
I tried to generate a 'waypoints' array using the polyline coordinates array by evenly dividing it and getting 8 coordinates in between and passing those in as the waypoints but it fails to render at all now. If I test the code using a coordinates array that was generated by drawing a route it works though, so I know the code is working. I'm presuming it fails because some of these coordinates may be slightly off the road (it's a polyline drawn from GPS positioning, so it's not 100% accurate), and Google doesn't just snap it to the nearest accepted location.
Can anyone think of a solution to this?
Here's code examples to make it a bit clearer:
// In the polyline app
var encoded_path = google.maps.geometry.encoding.encodePath(coordinate_array)
// In the route app
var coordinates = google.maps.geometry.encoding.decodePath(encoded_path);
var waypoints = [];
// Evenly get coordinates across the entire array to be used as waypoints
for (var i = 1; i <= 8; ++i) {
var index = Math.floor((coordinates.length/10) * i);
if (index >= coordinates.length - 1)
break;
waypoints.push({
'location': new google.maps.LatLng(coordinates[index].lat(), coordinates[index].lng()),
'stopover': false
});
}
var request = {
origin: coordinates[0],
destination: coordinates[coordinates.length - 1],
travelMode: google.maps.DirectionsTravelMode.DRIVING,
waypoints: waypoints
};
MapService.directionsService.route(request, function(response, status) {
if (status == google.maps.DirectionsStatus.OK) {
MapService.directionsDisplay.setDirections(response);
}
});
It's been a while and there's a better answer now, the Roads API:
https://developers.google.com/maps/documentation/roads/intro
Directions API is not intended for this use case, there are several good reasons to not even try:
Waypoints that are stop-over (default) will allow any direction of travel, in or out, when snapping to the nearest road, regardless of previous/next waypoints.
Waypoints that are not stop-over (via:) will be very strict when snapping to roads, typical GPS offset will throw it off and cause ZERO_RESULTS (no route)-
Even if all waypoints work out well, the route will be the best route for a generic driver, not necessarily the route followed by the vehicle that sampled the positions used as waypoints.
If a vehicle samples a position at the intersection of 2 roads at different altitudes (elevated pass, bridge, tunnel, etc.), if the GPS offset makes the point be in the wrong road, it can throw routing wildly off.
You can use the direction api to check the waypoints when it ends at a road: Map of all points below a certain time of travel?. Then delete the others to create a route from the entire polyline.
public String makeURL (double sourcelat, double sourcelog, double destlat, double destlog ){
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.googleapis.com/maps/api/directions/json");
urlString.append("?origin=");// from
urlString.append(Double.toString(sourcelat));
urlString.append(",");
urlString
.append(Double.toString( sourcelog));
urlString.append("&destination=");// to
urlString
.append(Double.toString( destlat));
urlString.append(",");
urlString.append(Double.toString( destlog));
urlString.append("&sensor=false&mode=driving");
return urlString.toString();
}
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;
}
public class JSONParser {
InputStream is = null;
JSONObject jObj = null;
String json = "";
// constructor
public JSONParser() {
}
public String getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
json = sb.toString();
is.close();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
return json;
}
}
public 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 = decodePoly(encodedString);
for(int z = 0; z<list.size()-1;z++){
LatLng src= list.get(z);
LatLng dest= list.get(z+1);
theMap.addPolyline(new PolylineOptions()
.add(src,dest)
.width(2)
.color(Color.BLUE).geodesic(true));
}
}
catch (JSONException e) {
}
}
private class connectAsyncTask extends AsyncTask<Void, Void, String>{
private ProgressDialog progressDialog;
String url;
connectAsyncTask(String urlPass){
url = urlPass;
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = new ProgressDialog(YOUR_Activity.this);
progressDialog.setMessage("Fetching route, Please wait...");
progressDialog.setIndeterminate(true);
progressDialog.show();
}
#Override
protected String doInBackground(Void... params) {
JSONParser jParser = new JSONParser();
String json = jParser.getJSONFromUrl(url);
return json;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
progressDialog.hide();
if(result!=null){
drawPath(result);
}
}
}
I'm about to trace with direction service the railway between two station.
The problem is I can't get the Lat/Lng of the two station, it get always a neighbour points.
The route is (search on google maps website) :
Ceres, TO to Stazione Porta Nuova, Corso Vittorio Emanuele II, 58, Torino
I need Lat/Lng of Ceres (train station) and Stazione Porta Nuova, Corso Vittorio Emanuele II, 58, Torino (train station). How can I get them?
So I can draw in my maps the same railway (brown line).
public class GetXMLTask
{
static double longitute;
static double latitude;
public JSONObject getLocationInfo(String address)
{
StringBuilder stringBuilder = new StringBuilder();
try
{
address = address.replaceAll(" ","%20");
HttpPost httppost = new HttpPost("http://maps.google.com/maps/api/geocode/json?address=" + address + "&sensor=false");
HttpClient client = new DefaultHttpClient();
HttpResponse response;
stringBuilder = new StringBuilder();
response = client.execute(httppost);
HttpEntity entity = response.getEntity();
InputStream stream = entity.getContent();
int b;
while ((b = stream.read()) != -1)
{
stringBuilder.append((char) b);
}
}
catch (ClientProtocolException e)
{
Log.i("getLocationInfo ClientProtocolException", e.toString());
}
catch (IOException e)
{
Log.i("getLocationInfo IOException", e.toString());
}
JSONObject jsonObject = new JSONObject();
try
{
jsonObject = new JSONObject(stringBuilder.toString());
}
catch (JSONException e)
{
Log.i("getLocationInfo JSONException", e.toString());
}
return jsonObject;
}
public ArrayList<Double> getLatLong(JSONObject jsonObject)
{
ArrayList<Double> latlng = new ArrayList<Double>();
try
{
longitute = ((JSONArray)jsonObject.get("results")).getJSONObject(0).getJSONObject("geometry").getJSONObject("location").getDouble("lng");
latitude = ((JSONArray)jsonObject.get("results")).getJSONObject(0).getJSONObject("geometry").getJSONObject("location").getDouble("lat");
latlng.add(latitude);
latlng.add(longitute);
}
catch (JSONException e)
{
longitute = 0;
latitude = 0;
Log.i("getLatLong", e.toString());
}
return latlng;
}
}
now we can call it inside our class by
latitude = new GetXMLTask().getLatLong(new GetXMLTask().getLocationInfo(address)).get(0);
longitude = new GetXMLTask().getLatLong(new GetXMLTask().getLocationInfo(address)).get(1);
I may not have the super optimised code , but this is working pretty fine for me , give it a try , just passed the address in your calling class