请问我一直在尝试开发一个应用程序，可以将地点列表及其坐标与用户的当前位置进行比较，并显示给定列表中附近地点的列表，我能够得到我的应用程序获取当前位置并显示到给定坐标的路线，但我不知道从这里开始的地方，从我将提供的坐标获取附近的地点列表。下面是我的java和xml代码。谢谢
Java文件
import java.io.BufferedReader;
import java.io.IOException;
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;
import org.json.JSONObject;
import android.graphics.Color;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;
public class MyLefkosa extends FragmentActivity {
GoogleMap map;
ArrayList<LatLng> markerPoints;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mygirne);
// Initializing
markerPoints = new ArrayList<LatLng>();
// Getting reference to SupportMapFragment of the activity_main
SupportMapFragment fm = (SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map);
// Getting Map for the SupportMapFragment
map = fm.getMap();
if(map!=null){
// Enable MyLocation Button in the Map
map.setMyLocationEnabled(true);
// change map type to hybrid
map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
// set traffic
map.setTrafficEnabled(true);
// get user location
// Setting onclick event listener for the map
LocationManager manager=(LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria=new Criteria();
String provider =manager.getBestProvider(criteria, true);
Location cloc=manager.getLastKnownLocation(provider);
double lat=35.177;
double lng =33.3456;
lat =cloc.getLatitude();
lng= cloc.getLongitude();
LatLng latlng = new LatLng (lat,lng);
map.moveCamera(CameraUpdateFactory.newLatLng(latlng));
map.animateCamera(CameraUpdateFactory.zoomTo(15));
map.addMarker(new MarkerOptions()
.title("Your Current Location")
.position(latlng));
LatLng LEFKOSA =
new LatLng(35.166666700000000000,33.366666699999996000);
map.addMarker(new MarkerOptions()
.position(LEFKOSA)
.title("LEFKOSA")
.snippet("LEFKOSA CITY CENTRE")
.icon(BitmapDescriptorFactory.defaultMarker(
BitmapDescriptorFactory.HUE_AZURE)));
// Getting URL to the Google Directions API
String url = getDirectionsUrl(latlng, LEFKOSA);
DownloadTask downloadTask = new DownloadTask();
// Start downloading json data from Google Directions API
downloadTask.execute(url);
}
}
private String getDirectionsUrl(LatLng latlng,LatLng LEFKOSA){
// Origin of route
String str_origin = "origin="+latlng.latitude+","+latlng.longitude;
// Destination of route
String str_dest = "destination="+LEFKOSA.latitude+","+LEFKOSA.longitude;
// Sensor enabled
String sensor = "sensor=true";
// Building the parameters to the web service
String parameters = str_origin+"&"+str_dest+"&"+sensor;
// Output format
String output = "json";
// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/directions/"+output+"?"+parameters;
return url;
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException{
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try{
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while( ( line = br.readLine()) != null){
sb.append(line);
}
data = sb.toString();
br.close();
}catch(Exception e){
Log.d("Exception while downloading url", e.toString());
}finally{
iStream.close();
urlConnection.disconnect();
}
return data;
}
// Fetches data from url passed
private class DownloadTask extends AsyncTask<String, Void, String>{
// Downloading data in non-ui thread
@Override
protected String doInBackground(String... url) {
// For storing data from web service
String data = "";
try{
// Fetching the data from web service
data = downloadUrl(url[0]);
}catch(Exception e){
Log.d("Background Task",e.toString());
}
return data;
}
// Executes in UI thread, after the execution of
// doInBackground()
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
ParserTask parserTask = new ParserTask();
// Invokes the thread for parsing the JSON data
parserTask.execute(result);
}
}
/** A class to parse the Google Places in JSON format */
private class ParserTask extends AsyncTask<String, Integer, List<List<HashMap<String,String>>> >{
// Parsing the data in non-ui thread
@Override
protected List<List<HashMap<String, String>>> doInBackground(String... jsonData) {
JSONObject jObject;
List<List<HashMap<String, String>>> routes = null;
try{
jObject = new JSONObject(jsonData[0]);
Directions parser = new Directions();
// Starts parsing data
routes = parser.parse(jObject);
}catch(Exception e){
e.printStackTrace();
}
return routes;
}
// Executes in UI thread, after the parsing process
@Override
protected void onPostExecute(List<List<HashMap<String, String>>> result) {
ArrayList<LatLng> points = null;
PolylineOptions lineOptions = null;
MarkerOptions markerOptions = new MarkerOptions();
// Traversing through all the routes
for(int i=0;i<result.size();i++){
points = new ArrayList<LatLng>();
lineOptions = new PolylineOptions();
// Fetching i-th route
List<HashMap<String, String>> path = result.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(5);
lineOptions.color(Color.CYAN);
}
// Drawing polyline in the Google Map for the i-th route
map.addPolyline(lineOptions);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.mygirne, menu);
return true;
}
}
xml文件
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.firsttry.cyptour.MyLefkosa" >
<fragment
android:id="@+id/map"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="com.google.android.gms.maps.SupportMapFragment" />
</RelativeLayout>
答案 0 :(得分：0)
尝试使用distnaceBetween()方法查找位置：http://developer.android.com/reference/android/location/Location.html