绘制到目标android maps v2的路径

我有一些代码在两个方向之间显示目标已初始化（已知位置）。完整代码如下所示：

package com.my.app;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;

import android.app.FragmentManager;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
//import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;
import android.support.v4.app.FragmentActivity;
import com.google.android.gms.maps.SupportMapFragment;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;



public class CobaMap2 extends FragmentActivity {
final int RQS_GooglePlayServices = 1;
private GoogleMap myMap;
double src_lat = -7.81016;
double src_long = 110.46860;
double dest_lat = -7.778031;
double dest_long = 110.494180;
MarkerOptions markerOptions;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map_layout2);

myMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
myMap.setMyLocationEnabled(true);
// Set Current Location
moveToMyLocation();}
private void moveToMyLocation()
{
LocationManager locationManager = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
if (location != null)
{
 myMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), 
location.getLongitude()), 13));
}



// choose map layout

RadioGroup rgViews = (RadioGroup) findViewById(R.id.rg_views);

rgViews.setOnCheckedChangeListener(new OnCheckedChangeListener() {

    @Override
    public void onCheckedChanged(RadioGroup group, int checkedId) {
        if(checkedId == R.id.rb_normal){
            myMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        }else if(checkedId == R.id.rb_satellite){
            myMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
        }else if(checkedId == R.id.rb_terrain){
            myMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);
        }

    }
});




LatLng srcLatLng = new LatLng(src_lat, src_long);
LatLng destLatLng = new LatLng(dest_lat, dest_long);

myMap.addMarker(new MarkerOptions()
.position(srcLatLng).title("Source place"));

myMap.animateCamera(CameraUpdateFactory.newLatLng(srcLatLng));

myMap.addMarker(new MarkerOptions()
.position(destLatLng).title("Destination place"));

// Enabling MyLocation in Google Map
myMap.setMyLocationEnabled(true);
myMap.getUiSettings().setZoomControlsEnabled(true);
myMap.getUiSettings().setCompassEnabled(true);
myMap.getUiSettings().setMyLocationButtonEnabled(true);
myMap.getUiSettings().setAllGesturesEnabled(true);
myMap.setTrafficEnabled(true);
myMap.animateCamera(CameraUpdateFactory.newLatLngZoom(srcLatLng,12));
        markerOptions = new MarkerOptions();


// Polyline line = myMap.addPolyline(new PolylineOptions().add(srcLatLng, destLatLng).width(5).color(Color.RED));

connectAsyncTask _connectAsyncTask = new connectAsyncTask();
         _connectAsyncTask.execute();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.cobamap, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_legalnotices:
String LicenseInfo = GooglePlayServicesUtil.getOpenSourceSoftwareLicenseInfo(
getApplicationContext());
AlertDialog.Builder LicenseDialog = new AlertDialog.Builder(CobaMap2.this);
LicenseDialog.setTitle("Legal Notices");
LicenseDialog.setMessage(LicenseInfo);
LicenseDialog.show();
return true;
}
return super.onOptionsItemSelected(item);
}

@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();

int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getApplicationContext());

if (resultCode == ConnectionResult.SUCCESS){
Toast.makeText(getApplicationContext(),
"isGooglePlayServicesAvailable SUCCESS",
Toast.LENGTH_LONG).show();
}else{
GooglePlayServicesUtil.getErrorDialog(resultCode, this, RQS_GooglePlayServices);
}

}

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(CobaMap2.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) {
// TODO Auto-generated method stub
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")){
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> directionPoint = decodePoly(_path);

PolylineOptions rectLine = new PolylineOptions().width(10).color(Color.BLUE);
for (int i = 0; i < directionPoint.size(); i++) {
rectLine.add(directionPoint.get(i));
}
// Adding route on the map
myMap.addPolyline(rectLine);
markerOptions.position(new LatLng(dest_lat, dest_long));
markerOptions.draggable(true);
myMap.addMarker(markerOptions);
}else{
showAlert("Unable to find the route");
}


}else{
showAlert("Unable to find the route");
}

progressDialog.dismiss();

}

}

Document doc = null;
private void fetchData()
{   
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.google.com/maps/api/directions/xml?origin=");
urlString.append(src_lat);
urlString.append(",");
urlString.append(src_long);
urlString.append("&destination=");//to
urlString.append(dest_lat);
urlString.append(",");
urlString.append(dest_long);
urlString.append("&sensor=true&mode=driving");
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();
}
}


private void showAlert(String message){
AlertDialog.Builder alert = new AlertDialog.Builder(CobaMap2.this);
alert.setTitle("Error");
alert.setCancelable(false);
alert.setMessage(message);
alert.setPositiveButton("Ok",new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub

}
});
alert.show();
}

private ArrayList<LatLng> decodePoly(String encoded) {
ArrayList<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 position = new LatLng((double) lat / 1E5, (double) lng / 1E5);
poly.add(position);
}
return poly;
}
}

初始化该位置的代码为：

LatLng srcLatLng = new LatLng(src_lat, src_long);
    LatLng destLatLng = new LatLng(dest_lat, dest_long);

问题是，如何从我的当前位置传递数据以设置源位置的数据并显示位置之间的路径。（来源：我的当前位置，目的地：已知位置）。我必须用什么方法？。我的意思是应用程序从我的当前位置显示到目标位置，并修改该代码？

检查此问题

在这篇文章中，您将获得使用多段线绘制从一个地方到另一个地方的正确路线的代码，还包括当前位置和目的地位置

编辑：

使用

里面

if (location != null)
{
src_lat=location.getLatitude() 
src_long=location.getLongitude()
 myMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), 
location.getLongitude()), 13));
}

编辑： 试用 更改：

Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));

到

---

谢谢你的回答，但是我更喜欢使用这个代码，因为某些原因。我不知道我必须做什么，我对android开发非常陌生：（好的，那么请让我知道你到底想做什么？你想把当前位置设置为源位置，而目标位置已经知道了吗？或者别的什么？是的，像这样。我想把我的当前位置设置为源位置。从我的源修改，而不是从其他源修改。你能帮我吗？是的，我试过你的答案，但警告说“找不到路线”，我想问题是当我将源lat和lng的值更改为零时，比如

double src_lat=0；double src_long=0；

声明的

src_lat

和

src_long

正确吗？这意味着你无法使用位置管理器获取当前位置！相机是否正在设置当前位置的动画？

if (location != null)
{
src_lat=location.getLatitude() 
src_long=location.getLongitude()
 myMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), 
location.getLongitude()), 13));
}

Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));

Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, true));