如何沿着现有道路在两点之间绘制路线？
How do I draw a route, along an existing road, between two points?
我想在我的 android 应用程序中显示两个位置之间的行车路线。我只想在路段上绘制路线。
关于stack overflow本身有几个答案，而且都是用同样的方法。使用 google 方向 API 获取从起点到目的地的方向，并在返回的点之间绘制折线。以下是一些使用此方法的答案。
但是，上述方法的问题是，当道路不直时，dawn rote 并不总是在道路的顶部，因为方向 API 只有 returns 指向你需要的地方从一条道路转向另一条道路（在路口）。它不提供同一路段弯道中的点详细信息。所以，当我在道路弯道很多的地区使用上述方法时，绘制的路线几乎总是不在路段的顶部。
我找到了 this 答案，它使用 javascript API 完成了我需要做的事情。在此解决方案中，绘制的路线很好地跟随道路，类似于 google 地图 android 应用程序。有人知道这是否可以在 android 应用程序中实现吗？
Google 地图 android 应用程序可以很好地绘制从一个点到另一个点的路线，使路线保持在道路上。有谁知道 Google 地图是如何做到这一点的？是否使用其他未公开的API？
事实上，您可以使用路线 API 网络服务提供的结果在 Google 地图 Android API 中绘制精确路线。如果您阅读 Directions API 的文档，您会看到该响应包含有关路线路段和路段的信息。每个步骤都有一个字段 polyline，在文档中描述为
polyline contains a single points object that holds an encoded polyline representation of the step. This polyline is an approximate (smoothed) path of the step.
因此，解决您的问题的主要思路是从 Directions API 获取响应，遍历路线和路段，对于每个路段获取 encoded polyline 并将其解码为坐标列表.完成后，您将获得构成路线的所有坐标的列表，不仅是每一步的起点和终点。
为简单起见，我建议对 Google 地图 Web 服务使用 Java 客户端库：
https://github.com/googlemaps/google-maps-services-java
使用此库，您可以避免为多段线实现自己的异步任务和解码功能。阅读文档以了解如何在您的项目中添加客户端库。
在Gradle中应该类似于
compile 'com.google.maps:google-maps-services:(insert latest version)'
compile 'org.slf4j:slf4j-nop:1.7.25'
我创建了一个简单的例子来演示它是如何工作的。看看我在代码中的评论
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
private String TAG = "so47492459";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
LatLng barcelona = new LatLng(41.385064,2.173403);
mMap.addMarker(new MarkerOptions().position(barcelona).title("Marker in Barcelona"));
LatLng madrid = new LatLng(40.416775,-3.70379);
mMap.addMarker(new MarkerOptions().position(madrid).title("Marker in Madrid"));
LatLng zaragoza = new LatLng(41.648823,-0.889085);
//Define list to get all latlng for the route
List<LatLng> path = new ArrayList();
//Execute Directions API request
GeoApiContext context = new GeoApiContext.Builder()
.apiKey("YOUR_API_KEY")
.build();
DirectionsApiRequest req = DirectionsApi.getDirections(context, "41.385064,2.173403", "40.416775,-3.70379");
try {
DirectionsResult res = req.await();
//Loop through legs and steps to get encoded polylines of each step
if (res.routes != null && res.routes.length > 0) {
DirectionsRoute route = res.routes[0];
if (route.legs !=null) {
for(int i=0; i<route.legs.length; i++) {
DirectionsLeg leg = route.legs[i];
if (leg.steps != null) {
for (int j=0; j<leg.steps.length;j++){
DirectionsStep step = leg.steps[j];
if (step.steps != null && step.steps.length >0) {
for (int k=0; k<step.steps.length;k++){
DirectionsStep step1 = step.steps[k];
EncodedPolyline points1 = step1.polyline;
if (points1 != null) {
//Decode polyline and add points to list of route coordinates
List<com.google.maps.model.LatLng> coords1 = points1.decodePath();
for (com.google.maps.model.LatLng coord1 : coords1) {
path.add(new LatLng(coord1.lat, coord1.lng));
}
}
}
} else {
EncodedPolyline points = step.polyline;
if (points != null) {
//Decode polyline and add points to list of route coordinates
List<com.google.maps.model.LatLng> coords = points.decodePath();
for (com.google.maps.model.LatLng coord : coords) {
path.add(new LatLng(coord.lat, coord.lng));
}
}
}
}
}
}
}
}
} catch(Exception ex) {
Log.e(TAG, ex.getLocalizedMessage());
}
//Draw the polyline
if (path.size() > 0) {
PolylineOptions opts = new PolylineOptions().addAll(path).color(Color.BLUE).width(5);
mMap.addPolyline(opts);
}
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(zaragoza, 6));
}
}
请注意，对于 Web 服务，您必须创建一个单独的 API 密钥，具有 Android 应用限制的 API 密钥将不适用于 Web 服务。
我的例子的结果如截图所示
您还可以从
下载完整的示例项目
https://github.com/xomena-so/so47492459
不要忘记将 API 键替换为您的。
希望对您有所帮助！
您可以使用这个 library, and it's simple, check example of usage：
Routing routing = new Routing.Builder()
.travelMode(AbstractRouting.TravelMode.DRIVING)
.withListener(this)
.alternativeRoutes(true)
.waypoints(start, end)
.build();
routing.execute();
@Override
public void onRoutingSuccess(List<Route> route, int shortestRouteIndex) {
progressDialog.dismiss();
CameraUpdate center = CameraUpdateFactory.newLatLng(start);
CameraUpdate zoom = CameraUpdateFactory.zoomTo(16);
map.moveCamera(center);
if(polylines.size()>0) {
for (Polyline poly : polylines) {
poly.remove();
}
}
polylines = new ArrayList<>();
// Add route(s) to the map.
for (int i = 0; i <route.size(); i++) {
//In case of more than 5 alternative routes
int colorIndex = i % COLORS.length;
PolylineOptions polyOptions = new PolylineOptions();
polyOptions.color(getResources().getColor(COLORS[colorIndex]));
polyOptions.width(10 + i * 3);
polyOptions.addAll(route.get(i).getPoints());
Polyline polyline = map.addPolyline(polyOptions);
polylines.add(polyline);
Toast.makeText(getApplicationContext(),"Route "+ (i+1) +": distance - "+ route.get(i).getDistanceValue()+": duration - "+ route.get(i).getDurationValue(),Toast.LENGTH_SHORT).show();
}
// Start marker
MarkerOptions options = new MarkerOptions();
options.position(start);
options.icon(BitmapDescriptorFactory.fromResource(R.drawable.start_blue));
map.addMarker(options);
// End marker
options = new MarkerOptions();
options.position(end);
options.icon(BitmapDescriptorFactory.fromResource(R.drawable.end_green));
map.addMarker(options);
}
如果您收到有关无钥匙访问的警告（you should have billing account 将其与钥匙一起使用）
，请不要忘记使用示例中的生成器添加 key
从 Google 控制台启用方向 API。
将 API_KEY 替换为 GetPathFromLocation.java class
import android.graphics.Color;
import android.os.AsyncTask;
import android.util.Log;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.PolylineOptions;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class GetPathFromLocation extends AsyncTask<String, Void, PolylineOptions> {
private String TAG = "GetPathFromLocation";
private String API_KEY = "Place_Your_API_Key";
private LatLng source, destination;
private DirectionPointListener resultCallback;
public GetPathFromLocation(LatLng source, LatLng destination, DirectionPointListener resultCallback) {
this.source = source;
this.destination = destination;
this.resultCallback = resultCallback;
}
public String getUrl(LatLng origin, LatLng dest) {
String str_origin = "origin=" + origin.latitude + "," + origin.longitude;
String str_dest = "destination=" + dest.latitude + "," + dest.longitude;
String sensor = "sensor=false";
String parameters = str_origin + "&" + str_dest + "&" + sensor;
String output = "json";
String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters + "&key=" + API_KEY;
return url;
}
@Override
protected PolylineOptions doInBackground(String... url) {
String data;
try {
InputStream inputStream = null;
HttpURLConnection connection = null;
try {
URL directionUrl = new URL(getUrl(source, destination));
connection = (HttpURLConnection) directionUrl.openConnection();
connection.connect();
inputStream = connection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuffer stringBuffer = new StringBuffer();
String line = "";
while ((line = bufferedReader.readLine()) != null) {
stringBuffer.append(line);
}
data = stringBuffer.toString();
bufferedReader.close();
} catch (Exception e) {
Log.e(TAG, "Exception : " + e.toString());
return null;
} finally {
inputStream.close();
connection.disconnect();
}
Log.e(TAG, "Background Task data : " + data);
JSONObject jsonObject;
List<List<HashMap<String, String>>> routes = null;
try {
jsonObject = new JSONObject(data);
// Starts parsing data
DirectionHelper helper = new DirectionHelper();
routes = helper.parse(jsonObject);
Log.e(TAG, "Executing Routes : "/*, routes.toString()*/);
ArrayList<LatLng> points;
PolylineOptions lineOptions = null;
// Traversing through all the routes
for (int i = 0; i < routes.size(); i++) {
points = new ArrayList<>();
lineOptions = new PolylineOptions();
// Fetching i-th route
List<HashMap<String, String>> path = routes.get(i);
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++) {
HashMap<String, String> point = path.get(j);
double lat = Double.parseDouble(point.get("lat"));
double lng = Double.parseDouble(point.get("lng"));
LatLng position = new LatLng(lat, lng);
points.add(position);
}
// Adding all the points in the route to LineOptions
lineOptions.addAll(points);
lineOptions.width(10);
lineOptions.color(Color.BLUE);
Log.e(TAG, "PolylineOptions Decoded");
}
// Drawing polyline in the Google Map for the i-th route
if (lineOptions != null) {
return lineOptions;
} else {
return null;
}
} catch (Exception e) {
Log.e(TAG, "Exception in Executing Routes : " + e.toString());
return null;
}
} catch (Exception e) {
Log.e(TAG, "Background Task Exception : " + e.toString());
return null;
}
}
@Override
protected void onPostExecute(PolylineOptions polylineOptions) {
super.onPostExecute(polylineOptions);
if (resultCallback != null && polylineOptions != null)
resultCallback.onPath(polylineOptions);
}
}
DirectionHelper.java
import com.google.android.gms.maps.model.LatLng;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class DirectionHelper {
public List<List<HashMap<String, String>>> parse(JSONObject jObject) {
List<List<HashMap<String, String>>> routes = new ArrayList<>();
JSONArray jRoutes;
JSONArray jLegs;
JSONArray jSteps;
try {
jRoutes = jObject.getJSONArray("routes");
/** Traversing all routes */
for (int i = 0; i < jRoutes.length(); i++) {
jLegs = ((JSONObject) jRoutes.get(i)).getJSONArray("legs");
List path = new ArrayList<>();
/** Traversing all legs */
for (int j = 0; j < jLegs.length(); j++) {
jSteps = ((JSONObject) jLegs.get(j)).getJSONArray("steps");
/** Traversing all steps */
for (int k = 0; k < jSteps.length(); k++) {
String polyline = "";
polyline = (String) ((JSONObject) ((JSONObject) jSteps.get(k)).get("polyline")).get("points");
List<LatLng> list = decodePoly(polyline);
/** Traversing all points */
for (int l = 0; l < list.size(); l++) {
HashMap<String, String> hm = new HashMap<>();
hm.put("lat", Double.toString((list.get(l)).latitude));
hm.put("lng", Double.toString((list.get(l)).longitude));
path.add(hm);
}
}
routes.add(path);
}
}
} catch (JSONException e) {
e.printStackTrace();
} catch (Exception e) {
}
return routes;
}
//Method to decode polyline points
private List<LatLng> decodePoly(String encoded) {
List<LatLng> poly = new ArrayList<>();
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;
}
}
DirectionPointListener.java
import com.google.android.gms.maps.model.PolylineOptions;
public interface DirectionPointListener {
public void onPath(PolylineOptions polyLine);
}
在Activity或片段
中使用
LatLng source = new LatLng(xx.xxxx, yy.yyyy);
LatLng destination = new LatLng(xx.xxxx, yy.yyyy);
new GetPathFromLocation(source, destination, new DirectionPointListener() {
@Override
public void onPath(PolylineOptions polyLine) {
yourMap.addPolyline(polyLine);
}
}).execute();
对我来说，我使用 OSM 作为 geojson 获取方向，然后使用 google maps utils
在 Google 地图上绘制路线
第一个
// build.gradle
dependencies {
implementation 'com.google.maps.android:android-maps-utils:0.5'
}
// in maps Activity
// mMap is Google map
// geoJsonData is the returend json object from directions api
// which in my case is OSM
GeoJsonLayer layer = new GeoJsonLayer(mMap, geoJsonData);
// now you can add the layer to the map
layer.addLayerToMap();
// congrats you draw the road between two points now :)
有关详细信息，请查看此 Google Maps Android GeoJson Utility。
快乐编码
我想在我的 android 应用程序中显示两个位置之间的行车路线。我只想在路段上绘制路线。
关于stack overflow本身有几个答案，而且都是用同样的方法。使用 google 方向 API 获取从起点到目的地的方向，并在返回的点之间绘制折线。以下是一些使用此方法的答案。
但是，上述方法的问题是，当道路不直时，dawn rote 并不总是在道路的顶部，因为方向 API 只有 returns 指向你需要的地方从一条道路转向另一条道路（在路口）。它不提供同一路段弯道中的点详细信息。所以，当我在道路弯道很多的地区使用上述方法时，绘制的路线几乎总是不在路段的顶部。
我找到了 this 答案，它使用 javascript API 完成了我需要做的事情。在此解决方案中，绘制的路线很好地跟随道路，类似于 google 地图 android 应用程序。有人知道这是否可以在 android 应用程序中实现吗？
Google 地图 android 应用程序可以很好地绘制从一个点到另一个点的路线，使路线保持在道路上。有谁知道 Google 地图是如何做到这一点的？是否使用其他未公开的API？
事实上，您可以使用路线 API 网络服务提供的结果在 Google 地图 Android API 中绘制精确路线。如果您阅读 Directions API 的文档，您会看到该响应包含有关路线路段和路段的信息。每个步骤都有一个字段 polyline，在文档中描述为
polyline contains a single points object that holds an encoded polyline representation of the step. This polyline is an approximate (smoothed) path of the step.
因此，解决您的问题的主要思路是从 Directions API 获取响应，遍历路线和路段，对于每个路段获取 encoded polyline 并将其解码为坐标列表.完成后，您将获得构成路线的所有坐标的列表，不仅是每一步的起点和终点。
为简单起见，我建议对 Google 地图 Web 服务使用 Java 客户端库：
https://github.com/googlemaps/google-maps-services-java
使用此库，您可以避免为多段线实现自己的异步任务和解码功能。阅读文档以了解如何在您的项目中添加客户端库。
在Gradle中应该类似于
compile 'com.google.maps:google-maps-services:(insert latest version)'
compile 'org.slf4j:slf4j-nop:1.7.25'
我创建了一个简单的例子来演示它是如何工作的。看看我在代码中的评论
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
private String TAG = "so47492459";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
LatLng barcelona = new LatLng(41.385064,2.173403);
mMap.addMarker(new MarkerOptions().position(barcelona).title("Marker in Barcelona"));
LatLng madrid = new LatLng(40.416775,-3.70379);
mMap.addMarker(new MarkerOptions().position(madrid).title("Marker in Madrid"));
LatLng zaragoza = new LatLng(41.648823,-0.889085);
//Define list to get all latlng for the route
List<LatLng> path = new ArrayList();
//Execute Directions API request
GeoApiContext context = new GeoApiContext.Builder()
.apiKey("YOUR_API_KEY")
.build();
DirectionsApiRequest req = DirectionsApi.getDirections(context, "41.385064,2.173403", "40.416775,-3.70379");
try {
DirectionsResult res = req.await();
//Loop through legs and steps to get encoded polylines of each step
if (res.routes != null && res.routes.length > 0) {
DirectionsRoute route = res.routes[0];
if (route.legs !=null) {
for(int i=0; i<route.legs.length; i++) {
DirectionsLeg leg = route.legs[i];
if (leg.steps != null) {
for (int j=0; j<leg.steps.length;j++){
DirectionsStep step = leg.steps[j];
if (step.steps != null && step.steps.length >0) {
for (int k=0; k<step.steps.length;k++){
DirectionsStep step1 = step.steps[k];
EncodedPolyline points1 = step1.polyline;
if (points1 != null) {
//Decode polyline and add points to list of route coordinates
List<com.google.maps.model.LatLng> coords1 = points1.decodePath();
for (com.google.maps.model.LatLng coord1 : coords1) {
path.add(new LatLng(coord1.lat, coord1.lng));
}
}
}
} else {
EncodedPolyline points = step.polyline;
if (points != null) {
//Decode polyline and add points to list of route coordinates
List<com.google.maps.model.LatLng> coords = points.decodePath();
for (com.google.maps.model.LatLng coord : coords) {
path.add(new LatLng(coord.lat, coord.lng));
}
}
}
}
}
}
}
}
} catch(Exception ex) {
Log.e(TAG, ex.getLocalizedMessage());
}
//Draw the polyline
if (path.size() > 0) {
PolylineOptions opts = new PolylineOptions().addAll(path).color(Color.BLUE).width(5);
mMap.addPolyline(opts);
}
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(zaragoza, 6));
}
}
请注意，对于 Web 服务，您必须创建一个单独的 API 密钥，具有 Android 应用限制的 API 密钥将不适用于 Web 服务。
我的例子的结果如截图所示
您还可以从
下载完整的示例项目https://github.com/xomena-so/so47492459
不要忘记将 API 键替换为您的。
希望对您有所帮助！
您可以使用这个 library, and it's simple, check example of usage：
Routing routing = new Routing.Builder()
.travelMode(AbstractRouting.TravelMode.DRIVING)
.withListener(this)
.alternativeRoutes(true)
.waypoints(start, end)
.build();
routing.execute();
@Override
public void onRoutingSuccess(List<Route> route, int shortestRouteIndex) {
progressDialog.dismiss();
CameraUpdate center = CameraUpdateFactory.newLatLng(start);
CameraUpdate zoom = CameraUpdateFactory.zoomTo(16);
map.moveCamera(center);
if(polylines.size()>0) {
for (Polyline poly : polylines) {
poly.remove();
}
}
polylines = new ArrayList<>();
// Add route(s) to the map.
for (int i = 0; i <route.size(); i++) {
//In case of more than 5 alternative routes
int colorIndex = i % COLORS.length;
PolylineOptions polyOptions = new PolylineOptions();
polyOptions.color(getResources().getColor(COLORS[colorIndex]));
polyOptions.width(10 + i * 3);
polyOptions.addAll(route.get(i).getPoints());
Polyline polyline = map.addPolyline(polyOptions);
polylines.add(polyline);
Toast.makeText(getApplicationContext(),"Route "+ (i+1) +": distance - "+ route.get(i).getDistanceValue()+": duration - "+ route.get(i).getDurationValue(),Toast.LENGTH_SHORT).show();
}
// Start marker
MarkerOptions options = new MarkerOptions();
options.position(start);
options.icon(BitmapDescriptorFactory.fromResource(R.drawable.start_blue));
map.addMarker(options);
// End marker
options = new MarkerOptions();
options.position(end);
options.icon(BitmapDescriptorFactory.fromResource(R.drawable.end_green));
map.addMarker(options);
}
如果您收到有关无钥匙访问的警告（you should have billing account 将其与钥匙一起使用）
，请不要忘记使用示例中的生成器添加key
从 Google 控制台启用方向 API。
将 API_KEY 替换为 GetPathFromLocation.java class
import android.graphics.Color;
import android.os.AsyncTask;
import android.util.Log;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.PolylineOptions;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class GetPathFromLocation extends AsyncTask<String, Void, PolylineOptions> {
private String TAG = "GetPathFromLocation";
private String API_KEY = "Place_Your_API_Key";
private LatLng source, destination;
private DirectionPointListener resultCallback;
public GetPathFromLocation(LatLng source, LatLng destination, DirectionPointListener resultCallback) {
this.source = source;
this.destination = destination;
this.resultCallback = resultCallback;
}
public String getUrl(LatLng origin, LatLng dest) {
String str_origin = "origin=" + origin.latitude + "," + origin.longitude;
String str_dest = "destination=" + dest.latitude + "," + dest.longitude;
String sensor = "sensor=false";
String parameters = str_origin + "&" + str_dest + "&" + sensor;
String output = "json";
String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters + "&key=" + API_KEY;
return url;
}
@Override
protected PolylineOptions doInBackground(String... url) {
String data;
try {
InputStream inputStream = null;
HttpURLConnection connection = null;
try {
URL directionUrl = new URL(getUrl(source, destination));
connection = (HttpURLConnection) directionUrl.openConnection();
connection.connect();
inputStream = connection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuffer stringBuffer = new StringBuffer();
String line = "";
while ((line = bufferedReader.readLine()) != null) {
stringBuffer.append(line);
}
data = stringBuffer.toString();
bufferedReader.close();
} catch (Exception e) {
Log.e(TAG, "Exception : " + e.toString());
return null;
} finally {
inputStream.close();
connection.disconnect();
}
Log.e(TAG, "Background Task data : " + data);
JSONObject jsonObject;
List<List<HashMap<String, String>>> routes = null;
try {
jsonObject = new JSONObject(data);
// Starts parsing data
DirectionHelper helper = new DirectionHelper();
routes = helper.parse(jsonObject);
Log.e(TAG, "Executing Routes : "/*, routes.toString()*/);
ArrayList<LatLng> points;
PolylineOptions lineOptions = null;
// Traversing through all the routes
for (int i = 0; i < routes.size(); i++) {
points = new ArrayList<>();
lineOptions = new PolylineOptions();
// Fetching i-th route
List<HashMap<String, String>> path = routes.get(i);
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++) {
HashMap<String, String> point = path.get(j);
double lat = Double.parseDouble(point.get("lat"));
double lng = Double.parseDouble(point.get("lng"));
LatLng position = new LatLng(lat, lng);
points.add(position);
}
// Adding all the points in the route to LineOptions
lineOptions.addAll(points);
lineOptions.width(10);
lineOptions.color(Color.BLUE);
Log.e(TAG, "PolylineOptions Decoded");
}
// Drawing polyline in the Google Map for the i-th route
if (lineOptions != null) {
return lineOptions;
} else {
return null;
}
} catch (Exception e) {
Log.e(TAG, "Exception in Executing Routes : " + e.toString());
return null;
}
} catch (Exception e) {
Log.e(TAG, "Background Task Exception : " + e.toString());
return null;
}
}
@Override
protected void onPostExecute(PolylineOptions polylineOptions) {
super.onPostExecute(polylineOptions);
if (resultCallback != null && polylineOptions != null)
resultCallback.onPath(polylineOptions);
}
}
DirectionHelper.java
import com.google.android.gms.maps.model.LatLng;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class DirectionHelper {
public List<List<HashMap<String, String>>> parse(JSONObject jObject) {
List<List<HashMap<String, String>>> routes = new ArrayList<>();
JSONArray jRoutes;
JSONArray jLegs;
JSONArray jSteps;
try {
jRoutes = jObject.getJSONArray("routes");
/** Traversing all routes */
for (int i = 0; i < jRoutes.length(); i++) {
jLegs = ((JSONObject) jRoutes.get(i)).getJSONArray("legs");
List path = new ArrayList<>();
/** Traversing all legs */
for (int j = 0; j < jLegs.length(); j++) {
jSteps = ((JSONObject) jLegs.get(j)).getJSONArray("steps");
/** Traversing all steps */
for (int k = 0; k < jSteps.length(); k++) {
String polyline = "";
polyline = (String) ((JSONObject) ((JSONObject) jSteps.get(k)).get("polyline")).get("points");
List<LatLng> list = decodePoly(polyline);
/** Traversing all points */
for (int l = 0; l < list.size(); l++) {
HashMap<String, String> hm = new HashMap<>();
hm.put("lat", Double.toString((list.get(l)).latitude));
hm.put("lng", Double.toString((list.get(l)).longitude));
path.add(hm);
}
}
routes.add(path);
}
}
} catch (JSONException e) {
e.printStackTrace();
} catch (Exception e) {
}
return routes;
}
//Method to decode polyline points
private List<LatLng> decodePoly(String encoded) {
List<LatLng> poly = new ArrayList<>();
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;
}
}
DirectionPointListener.java
import com.google.android.gms.maps.model.PolylineOptions;
public interface DirectionPointListener {
public void onPath(PolylineOptions polyLine);
}
在Activity或片段
中使用LatLng source = new LatLng(xx.xxxx, yy.yyyy);
LatLng destination = new LatLng(xx.xxxx, yy.yyyy);
new GetPathFromLocation(source, destination, new DirectionPointListener() {
@Override
public void onPath(PolylineOptions polyLine) {
yourMap.addPolyline(polyLine);
}
}).execute();
对我来说，我使用 OSM 作为 geojson 获取方向，然后使用 google maps utils
在 Google 地图上绘制路线
第一个
// build.gradle
dependencies {
implementation 'com.google.maps.android:android-maps-utils:0.5'
}
// in maps Activity
// mMap is Google map
// geoJsonData is the returend json object from directions api
// which in my case is OSM
GeoJsonLayer layer = new GeoJsonLayer(mMap, geoJsonData);
// now you can add the layer to the map
layer.addLayerToMap();
// congrats you draw the road between two points now :)
有关详细信息，请查看此 Google Maps Android GeoJson Utility。
快乐编码