将这些添加到您的项目中
private class draw_ConnectAsyncTask extends AsyncTask<Void, Void, String>
{
String url;
draw_ConnectAsyncTask(String urlPass) {
url = urlPass;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@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);
if (result != null) {
drawPath(result);
}
}
JSONParser.java
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static 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 {
//decoding from bytes to char using "iso-8859-1"
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;
}
}
并添加这些方法
public String makeURL(double sourcelat, double sourcelog, double destlat, double destlog)
{
//make the url that will be passed to the JSONParser
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&alternatives=false");
return urlString.toString();
}
public void drawPath(String result)
{
try {
//Transform the string into a json object
final JSONObject json = new JSONObject(result);
//retrieving and decoding the polylineInitial
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);
rectLine = new PolylineOptions().width(8).color(
Color.BLUE);
//drawing the polyline by traversing all the LatLang the the list
for (int z = 0; z < list.size(); z++) {
rectLine.add(list.get(z));
}
polyline = map.addPolyline(rectLine);
} catch (JSONException e) {
e.printStackTrace();
}
}
private List<LatLng> decodePoly(String encoded)
{
//translating the encoded string to a list we can understand in android map
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;
}
然后像这样调用 AsynTask
draw_ConnectAsyncTask(makeURL(double,double,double,double));