Question

我有以下代码，它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，绘制的线条缺少一些像素！

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;
    }
}

代码工作正常并且从一个地方到另一个地方绘制路线但没有绘制交互式路线

Screent Shot： - enter image description here

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

不要创建太多的短Polyline，而只需创建一个像这里：

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);

我也不确定当你的分数彼此如此接近时你应该使用geodesic。

Answer 2

我已经创建了几个地图教程，涵盖了你需要的东西

Animating the map介绍了如何根据一组LatLng创建折线。 Using Google APIs on your map : Directions and Places介绍了如何使用Directions API并在路径上设置标记动画。

看看这两个教程以及包含示例应用的Github project。

它包含一些使您的代码更清晰，更高效的提示：

使用Google HTTP Library实现更高效的API访问和轻松的JSON处理。
将google-map-utils库用于与地图相关的功能（如解码折线）
制作动画标记

Answer 3

您可以使用此方法在googleMap上绘制折线

// Draw polyline on map
public void drawPolyLineOnMap(List<LatLng> list) {
    PolylineOptions polyOptions = new PolylineOptions();
    polyOptions.color(Color.RED);
    polyOptions.width(5);
    polyOptions.addAll(list);

    googleMap.clear();
    googleMap.addPolyline(polyOptions);

    LatLngBounds.Builder builder = new LatLngBounds.Builder();
    for (LatLng latLng : list) {
        builder.include(latLng);
    }

    final LatLngBounds bounds = builder.build();

    //BOUND_PADDING is an int to specify padding of bound.. try 100.
    CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bounds, BOUND_PADDING);
    googleMap.animateCamera(cu);
}

如果你没有，你需要在你的gradle中添加这一行。

compile 'com.google.android.gms:play-services-maps:8.4.0'

Answer 4

您应该使用options.addAll(allPoints);代替options.add(point);

Answer 5

使用Google Maps投影API在叠加视图上绘制折线可以使我们做很多事情。选中具有示例的repo。

如何在路线google maps v2 android上绘制交互式Polyline

5 个答案: