Question

如何在谷歌地图上获取和显示方向，如下面的截图所示？ Screenshot

Answer 1

尝试此代码，您需要google api pass key访问开发人员获取该密钥尝试这个代码可行。

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.json.JSONObject;

import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;

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.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;

public class PathGoogleMapActivity extends FragmentActivity {

    private static final LatLng LOWER_MANHATTAN = new LatLng(40.722543,
            -73.998585);
    private static final LatLng BROOKLYN_BRIDGE = new LatLng(40.7057, -73.9964);
    private static final LatLng WALL_STREET = new LatLng(40.7064, -74.0094);

    GoogleMap googleMap;
    final String TAG = "PathGoogleMapActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_path_google_map);
        SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        googleMap = fm.getMap();

        MarkerOptions options = new MarkerOptions();
        options.position(LOWER_MANHATTAN);
        options.position(BROOKLYN_BRIDGE);
        options.position(WALL_STREET);
        googleMap.addMarker(options);
        String url = getMapsApiDirectionsUrl();
        ReadTask downloadTask = new ReadTask();
        downloadTask.execute(url);

        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(BROOKLYN_BRIDGE,
                13));
        addMarkers();

    }

    private String getMapsApiDirectionsUrl() {
        String waypoints = "waypoints=optimize:true|"
                + LOWER_MANHATTAN.latitude + "," + LOWER_MANHATTAN.longitude
                + "|" + "|" + BROOKLYN_BRIDGE.latitude + ","
                + BROOKLYN_BRIDGE.longitude + "|" + WALL_STREET.latitude + ","
                + WALL_STREET.longitude;

        String sensor = "sensor=false";
        String params = waypoints + "&" + sensor;
        String output = "json";
        String url = "https://maps.googleapis.com/maps/api/directions/"
                + output + "?" + params;
        return url;
    }

    private void addMarkers() {
        if (googleMap != null) {
            googleMap.addMarker(new MarkerOptions().position(BROOKLYN_BRIDGE)
                    .title("First Point"));
            googleMap.addMarker(new MarkerOptions().position(LOWER_MANHATTAN)
                    .title("Second Point"));
            googleMap.addMarker(new MarkerOptions().position(WALL_STREET)
                    .title("Third Point"));
        }
    }

    private class ReadTask extends AsyncTask<String, Void, String> {
        @Override
        protected String doInBackground(String... url) {
            String data = "";
            try {
                HttpConnection http = new HttpConnection();
                data = http.readUrl(url[0]);
            } catch (Exception e) {
                Log.d("Background Task", e.toString());
            }
            return data;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            new ParserTask().execute(result);
        }
    }

    private class ParserTask extends
            AsyncTask<String, Integer, List<List<HashMap<String, String>>>> {

        @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]);
                PathJSONParser parser = new PathJSONParser();
                routes = parser.parse(jObject);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return routes;
        }

        @Override
        protected void onPostExecute(List<List<HashMap<String, String>>> routes) {
            ArrayList<LatLng> points = null;
            PolylineOptions polyLineOptions = null;

            // traversing through routes
            for (int i = 0; i < routes.size(); i++) {
                points = new ArrayList<LatLng>();
                polyLineOptions = new PolylineOptions();
                List<HashMap<String, String>> path = routes.get(i);

                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);
                }

                polyLineOptions.addAll(points);
                polyLineOptions.width(2);
                polyLineOptions.color(Color.BLUE);
            }

            googleMap.addPolyline(polyLineOptions);
        }
    }
}

要获得绘制路径的说明，我使用了Google Directions API。我们只是使用HTTP请求命中给定的URL并获得json响应。此Google服务会计算指定位置之间的路线。

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 android.util.Log;

public class HttpConnection {
    public String readUrl(String mapsApiDirectionsUrl) throws IOException {
        String data = "";
        InputStream iStream = null;
        HttpURLConnection urlConnection = null;
        try {
            URL url = new URL(mapsApiDirectionsUrl);
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.connect();
            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 reading url", e.toString());
        } finally {
            iStream.close();
            urlConnection.disconnect();
        }
        return data;
    }

}

这最后一堂课jasonparser将为你指明方向

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.google.android.gms.maps.model.LatLng;

public class PathJSONParser {

    public List<List<HashMap<String, String>>> parse(JSONObject jObject) {
        List<List<HashMap<String, String>>> routes = new ArrayList<List<HashMap<String, String>>>();
        JSONArray jRoutes = null;
        JSONArray jLegs = null;
        JSONArray jSteps = null;
        try {
            jRoutes = jObject.getJSONArray("routes");
            /** Traversing all routes */
            for (int i = 0; i < jRoutes.length(); i++) {
                jLegs = ((JSONObject) jRoutes.get(i)).getJSONArray("legs");
                List<HashMap<String, String>> path = new ArrayList<HashMap<String, String>>();

                /** Traversing all legs */
                for (int j = 0; j < jLegs.length(); j++) {
                    jSteps = ((JSONObject) jLegs.get(j)).getJSONArray("steps");

                    /** Traversing all steps */
                    for (int k = 0; k < jSteps.length(); k++) {
                        String polyline = "";
                        polyline = (String) ((JSONObject) ((JSONObject) jSteps
                                .get(k)).get("polyline")).get("points");
                        List<LatLng> list = decodePoly(polyline);

                        /** Traversing all points */
                        for (int l = 0; l < list.size(); l++) {
                            HashMap<String, String> hm = new HashMap<String, String>();
                            hm.put("lat",
                                    Double.toString(((LatLng) list.get(l)).latitude));
                            hm.put("lng",
                                    Double.toString(((LatLng) list.get(l)).longitude));
                            path.add(hm);
                        }
                    }
                    routes.add(path);
                }
            }

        } catch (JSONException e) {
            e.printStackTrace();
        } catch (Exception e) {
        }
        return routes;
    }

    /**
     * Method Courtesy :
     * jeffreysambells.com/2010/05/27
     * /decoding-polylines-from-google-maps-direction-api-with-java
     * */
    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;
    }
}

下面有xmal和manifestfiles

activity_path_google_map.xml
<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"
    tools:context=".TaskRoadMap" >

   <fragment
        android:id="@+id/map"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        class="com.google.android.gms.maps.SupportMapFragment"/>

</RelativeLayout>

你的带有权限的manifestfile

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.javapapers.android.maps.path"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <permission
        android:name="com.javapapers.android.maps.path.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-permission android:name="com.javapapers.android.maps.path.permission.MAPS_RECEIVE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.javapapers.android.maps.path.PathGoogleMapActivity"
            android:label="@string/title_activity_path_google_map" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="AIzaSyARCTcX8bABCDE_ohscNcALAak-HnjTO5s" />

        <meta-data 
            android:name="com.google.android.gms.version" 
            android:value="@integer/google_play_services_version" />

    </application>

</manifest>

Android - 在谷歌地图上显示方向

1 个答案: