android - 如何在路线谷歌地图v2 android上绘制交互式折线

Question

我有以下 代码为我绘制折线并且工作正常，但问题是它没有绘制交互式折线，绘制的线缺少一些像素!

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;

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.JSONArray;
import org.json.JSONObject;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
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.Polyline;
import com.google.android.gms.maps.model.PolylineOptions;

import android.app.ProgressDialog;
import android.content.Context;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class testRoute extends FragmentActivity implements OnClickListener {

    private GoogleMap myMap;
    Polyline line;
    Context context;

    // Static LatLng
    LatLng startLatLng = new LatLng(30.707104, 76.690749);
    LatLng endLatLng = new LatLng(30.721419, 76.730017);

    public void onCreate(Bundle bd) {
        super.onCreate(bd);
        setContentView(R.layout.passanger_home_call);
        context = testRoute.this;

        // Temp GetTrails Button
        Button btntemp = (Button) findViewById(R.id.btn_pass_home_call_temp);
        btntemp.setOnClickListener(this);

        // GoogleMap myMap
        myMap = ((SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map_pass_home_call)).getMap();
        myMap.setMyLocationEnabled(true);
        myMap.moveCamera(CameraUpdateFactory.newLatLng(startLatLng));
        myMap.animateCamera(CameraUpdateFactory.zoomTo(12));

        // Now auto clicking the button
        btntemp.performClick();
    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {
        case R.id.btn_pass_home_call_temp:
            String urlTopass = makeURL(startLatLng.latitude,
                    startLatLng.longitude, endLatLng.latitude,
                    endLatLng.longitude);
            new connectAsyncTask(urlTopass).execute();
            break;

        default:
            break;
        }

    }

    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(context);
            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);
            }
        }
    }

    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");
        return urlString.toString();
    }

    public class JSONParser {

        InputStream is = null;
        JSONObject jObj = null;
        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;

        }
    }

    public void drawPath(String result) {
        if (line != null) {
            myMap.clear();
        }
        myMap.addMarker(new MarkerOptions().position(endLatLng).icon(
                BitmapDescriptorFactory.fromResource(R.drawable.redpin_marker)));
        myMap.addMarker(new MarkerOptions().position(startLatLng).icon(
                BitmapDescriptorFactory.fromResource(R.drawable.redpin_marker)));
        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);

            for (int z = 0; z < list.size() - 1; z++) {
                LatLng src = list.get(z);
                LatLng dest = list.get(z + 1);
                line = myMap.addPolyline(new PolylineOptions()
                        .add(new LatLng(src.latitude, src.longitude),
                                new LatLng(dest.latitude, dest.longitude))
                        .width(5).color(Color.BLUE).geodesic(true));
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    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;
    }
}

代码运行良好，绘制从一个地方到另一个地方的路线，但没有绘制交互式路线

屏幕截图:-

我认为问题在于我的 drawPath() 方法:

public void drawPath(String result) {
        if (line != null) {
            myMap.clear();
        }
        myMap.addMarker(new MarkerOptions().position(endLatLng).icon(
                BitmapDescriptorFactory.fromResource(R.drawable.redpin_marker)));
        myMap.addMarker(new MarkerOptions().position(startLatLng).icon(
                BitmapDescriptorFactory.fromResource(R.drawable.redpin_marker)));
        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);

            for (int z = 0; z < list.size() - 1; z++) {
                LatLng src = list.get(z);
                LatLng dest = list.get(z + 1);
                line = myMap.addPolyline(new PolylineOptions()
                        .add(new LatLng(src.latitude, src.longitude),
                                new LatLng(dest.latitude, dest.longitude))
                        .width(5).color(Color.BLUE).geodesic(true));
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

忽略标记只是建议我添加交互式折线？

Answer 1

与其创建太多短的Polyline，不如创建一个像这里这样的:

PolylineOptions options = new PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
for (int z = 0; z < list.size(); z++) {
    LatLng point = list.get(z);
    options.add(point);
}
line = myMap.addPolyline(options);

当您的点彼此如此接近时，我也不确定您是否应该使用 geodesic。