使用Google Maps Android API v2绘制两点之间的路径 [英] Draw path between two points using Google Maps Android API v2

问题描述

谷歌改变了Android的地图API并引入了API V2。以前的绘制路径代码不适用于API V2。

我已经设法使用API​​ V2绘制路径。我已经搜索了很多解决方案，但没有找到任何答案。所以我正在分享它的答案。

解决方案

首先，我们将获得源点和目的点之间的路线。然后我们将这些属性传递给下面的函数。
$ b $ pre $ 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& alternatives = true）;
urlString.append（& key = YOUR_API_KEY）;
return urlString.toString（）;



$ b $ p
$ b

这个函数将使我们发送的url获得方向API响应。然后我们将解析这个回应。解析器类是



  public class JSONParser {
 
 static InputStream is = null; 
 static JSONObject jObj = null; 
 static String json =; 
 //构造函数
 public JSONParser（）{
} 
 public String getJSONFromUrl（String url）{
 
 //发出HTTP请求
尝试{
 // 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（）; 
} 
尝试{
 BufferedReader reader = new BufferedReader（new InputStreamReader（
 is，iso-8859-1），8）; 
 StringBuilder sb = new StringBuilder（）; 
 String line = null; （（line = reader.readLine（））！= null）{
 sb.append（line +\\\
）; 
 while 
} 
 
 json = sb.toString（）; 
 is.close（）; 
} catch（Exception e）{
 Log.e（Buffer Error，Error conversion result+ e.toString（））; 
} 
返回json; 
 
 
 
 
 
 
 $ b 
这个解析器会返回字符串。我们会这样称呼它。
  JSONParser jParser = new JSONParser（）; 
 String json = jParser.getJSONFromUrl（url）; 
  
现在我们将把这个字符串发送到drawpath函数。 drawpath函数是 
 
 
  public void drawPath（String result）{
 
 try {
 //将字符串转换为json对象
 final JSONObject json = new JSONObject（result）; 
 JSONArray routeArray = json.getJSONArray（routes）; 
 JSONObject routes = routeArray.getJSONObject（0）; 
 JSONObject overviewPolylines = routes.getJSONObject（overview_polyline）; 
字符串encodedString = overviewPolylines.getString（points）; 
列表< LatLng> list = decodePoly（encodedString）; 
 Polyline line = mMap.addPolyline（new PolylineOptions（）
 .addAll（list）
 .width（12）
 .color（Color.parseColor（＃05b1fb）） // Google地图蓝色
 .geodesic（true）
）; （int z = 0; z< list.size（） -  1; z ++）{
 LatLng src = list.get（z）; 
 / * 
。 
 LatLng dest = list.get（z + 1）; 
 Polyline line = mMap.addPolyline（new PolylineOptions（）
 .add（new LatLng（src.latitude，src.longitude），new LatLng（dest.latitude，dest.longitude））
 .width（2）
 .color（Color.BLUE）.geodesic（true））; 
 
 
 
 catch（JSONException e）{
 
} 
} 
  
以上代码将在mMap上绘制路径。 decodePoly的代码是 
 
 
  private List< LatLng> decodePoly（字符串编码）{
 
 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）<<转移; 
 shift + = 5; 
} while（b> = 0x20）; 
 int dlat =（（result& 1）！= 0？〜（result>> 1）:( result>> 1））; 
 lat + = dlat; 
 
 shift = 0; 
结果= 0; 
 do {
 b = encoded.charAt（index ++） -  63; 
 result | =（b& 0x1f）<<转移; 
 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; 
 
 
 
 
 
 $ b 
由于方向调用可能需要时间，所以我们将在异步任务中完成所有这些。 
我的异步任务是 
 
 
  private class connectAsyncTask extends AsyncTask< Void，Void，String> {
 private ProgressDialog progressDialog; 
字符串网址; 
 connectAsyncTask（String urlPass）{
 url = urlPass; 
 
 @Override 
保护void onPreExecute（）{
 // TODO自动生成的方法存根
 super.onPreExecute（）; 
 progressDialog = new ProgressDialog（MainActivity.this）; 
 progressDialog.setMessage（获取路由，请稍候...）; 
 progressDialog.setIndeterminate（true）; 
 progressDialog.show（）; 
} 
 @Override 
 protected String doInBackground（Void ... params）{
 JSONParser jParser = new JSONParser（）; 
 String json = jParser.getJSONFromUrl（url）; 
返回json; 
} 
 @Override 
 protected void onPostExecute（String result）{
 super.onPostExecute（result）; 
 progressDialog.hide（）; 
 if（result！= null）{
 drawPath（result）; 
} 
} 
} 
  
我希望这会有所帮助。  
Google changed its map API for Android and introduced API V2. The previous codes for drawing path are not working with API V2.

I have managed to draw a path with API V2. I had searched a lot for the solution but did not find any answer. So I am sharing its answer.   
解决方案
First of all we will get source and destination points between which we have to draw route. Then we will pass these attribute to below function.
 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&alternatives=true");
        urlString.append("&key=YOUR_API_KEY");
        return urlString.toString();
 }
This function will make the url that we will send to get Direction API response. Then we will parse that response . The parser class is
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 {
            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;

    }
}
This parser will return us string. We will call it like that.
JSONParser jParser = new JSONParser();
String json = jParser.getJSONFromUrl(url);
Now we  will send this string to our drawpath function. The drawpath function is 
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);
           Polyline line = mMap.addPolyline(new PolylineOptions()
                                    .addAll(list)
                                    .width(12)
                                    .color(Color.parseColor("#05b1fb"))//Google maps blue color
                                    .geodesic(true)
                    );
           /*
           for(int z = 0; z<list.size()-1;z++){
                LatLng src= list.get(z);
                LatLng dest= list.get(z+1);
                Polyline line = mMap.addPolyline(new PolylineOptions()
                .add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude,   dest.longitude))
                .width(2)
                .color(Color.BLUE).geodesic(true));
            }
           */
    } 
    catch (JSONException e) {

    }
} 
Above code will draw the path on mMap. The code of decodePoly is
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;
}
As direction call may take time so we will do all this in Asynchronous task.
My Asynchronous task was 
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(MainActivity.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 hope it will help.

                        
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