Question

注意：抱歉我的英语不好，因为英语不是我的母语，我使用了谷歌翻译。

我正在开发一款Android地图应用，用户可以在其中找到他们的朋友＆＃39;当前位置。为了存储当前位置，我正在使用Firebase实时数据库。在Lalit Singh之前的帮助下，它现在显示时间和距离，但仍未在两个不同的地方更新Polylines。我的更新代码如下。

mapsActivity.java（我从火基地获取朋友位置，并更新时间，距离和折线方法）

  public void proceed(final View view) {

    DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Email");

    ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                UserInformation details = dataSnapshot1.getValue(UserInformation.class);

                if (mMap != null) {
                    mMap.clear();
                }

                MarkerOptions markerOptions = new MarkerOptions();
                LatLng latLng1 = new LatLng(details.getLatitude(), details.getLongitude());
                markerOptions.position(latLng1);
                markerOptions.title(String.valueOf(latLng1));
                mMap.addMarker(markerOptions).setIcon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
                mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
                mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng1));
                mMap.animateCamera(CameraUpdateFactory.zoomTo(14));

                distance_task.getDirectionsUrl(latLng1, markerOptions.getPosition());
                distance_task.setLoadListener(new CalculateDistanceTime.taskCompleteListener() {
                    @Override
                    public void taskCompleted(String[] time_distance) {
                        text1.setText(time_distance[0]); //Distance
                        text2.setText(time_distance[1]); //Time
                    }
                });

                String url = getDirectionsUrl(latLng1, markerOptions.getPosition());
                DownloadTask downloadTask = new DownloadTask();
                downloadTask.execute(url);
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}

CalculateDistanceTime.java（添加了新类）

class CalculateDistanceTime {     private taskCompleteListener
mTaskListener; private Context mContext;      
CalculateDistanceTime(Context context) {
mContext = context; }     void setLoadListener(taskCompleteListener taskListener) {
mTaskListener = taskListener; }        void getDirectionsUrl(LatLng origin, LatLng dest) {

// Origin of route
String str_origin = "origin=" + origin.latitude + "," + origin.longitude;

// Destination of route
String str_dest = "destination=" + dest.latitude + "," + dest.longitude;


// Sensor enabled
String sensor = "sensor=false";

// Building the parameters to the web service
String parameters = str_origin + "&" + str_dest + "&" + sensor;

// Output format
String output = "json";

// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;


DownloadTask downloadTask = new DownloadTask();

// Start downloading json data from Google Directions API

downloadTask.execute(url); }

private String downloadUrl(String strUrl) throws IOException {
String data = "";
HttpURLConnection urlConnection;
URL url = new URL(strUrl);

// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();

// Connecting to url
urlConnection.connect();

// Reading data from url
try (InputStream iStream = urlConnection.getInputStream()) {
    BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

    StringBuilder sb = new StringBuilder();

    String line;
    while ((line = br.readLine()) != null) {
        sb.append(line);
    }

    data = sb.toString();

    br.close();

} catch (Exception e) {
    Log.d("Excp. while downloading", e.toString());
} finally {
    urlConnection.disconnect();
}
return data; }

interface taskCompleteListener {
void taskCompleted(String[] time_distance); }

private class DownloadTask extends AsyncTask<String, Void, String> {

// Downloading data in non-ui thread
@Override
protected String doInBackground(String... url) {

    // For storing data from web service
    String data = "";

    try {
        // Fetching the data from web service
        data = downloadUrl(url[0]);
    } catch (Exception e) {
        Log.d("Background Task", e.toString());
    }
    return data;
}

// Executes in UI thread, after the execution of
// doInBackground()
@Override
protected void onPostExecute(String result) {
    super.onPostExecute(result);

    ParserTask parserTask = new ParserTask();

    // Invokes the thread for parsing the JSON data
    parserTask.execute(result);

} }

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

// Parsing the data in non-ui thread
@Override
protected List<HashMap<String, String>> doInBackground(String... jsonData) {

    JSONObject jObject;
    List<HashMap<String, String>> routes = null;

    try {
        jObject = new JSONObject(jsonData[0]);
        DistanceTimeParser parser = new DistanceTimeParser();

        // Starts parsing data
        routes = parser.parse(jObject);
    } catch (Exception e) {
        e.printStackTrace();
    }
    return routes;
}

// Executes in UI thread, after the parsing process
@Override
protected void onPostExecute(List<HashMap<String, String>> result) {

    String duration_distance = "";


    if (result.size() < 1) {
        Log.e("Error : ", "No Points found");
        return;
    }


    String[] date_dist = new String[2];

    // Traversing through all the routes
    for (int i = 0; i < result.size(); i++) {

        // Fetching i-th route
        HashMap<String, String> tmpData = result.get(i);
        Set<String> key = tmpData.keySet();
        Iterator it = key.iterator();
        while (it.hasNext()) {
            String hmKey = (String) it.next();
            duration_distance = tmpData.get(hmKey);

            System.out.println("Key: " + hmKey + " & Data: " + duration_distance);

            it.remove(); // avoids a ConcurrentModificationException
        }

        date_dist[i] = duration_distance;
    }

    mTaskListener.taskCompleted(date_dist);
}   } }

DistanceTimeParser.java（添加了新类）

public class DistanceTimeParser {
public List<HashMap<String, String>> parse(JSONObject jObject) {


    List<HashMap<String, String>> routes = new ArrayList<HashMap<String, String>>();
    JSONArray jRoutes = null;
    JSONArray jLegs = null;

    JSONObject jDistance = null;
    JSONObject jDuration = null;

    try {

        jRoutes = jObject.getJSONArray("routes");

        jLegs = ((JSONObject) jRoutes.get(0)).getJSONArray("legs");

        List<HashMap<String, String>> path = new ArrayList<HashMap<String, String>>();


        /** Getting distance from the json data */
        jDistance = ((JSONObject) jLegs.get(0)).getJSONObject("distance");
        HashMap<String, String> hmDistance = new HashMap<String, String>();
        hmDistance.put("distance", jDistance.getString("text"));

        /** Getting duration from the json data */
        jDuration = ((JSONObject) jLegs.get(0)).getJSONObject("duration");
        HashMap<String, String> hmDuration = new HashMap<String, String>();
        hmDuration.put("duration", jDuration.getString("text"));

        routes.add(hmDistance);

        routes.add(hmDuration);

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

    return routes;
} }

DirectionsJSONParser.java（添加了新类）

public class DirectionsJSONParser {

List<List<HashMap<String,String>>> parse(JSONObject jObject){

    List<List<HashMap<String, String>>> routes = new ArrayList<>() ;
    JSONArray jRoutes ;
    JSONArray jLegs ;
    JSONArray jSteps ;

    try {

        jRoutes = jObject.getJSONArray("routes");


        for(int i=0;i<jRoutes.length();i++){
            jLegs = ( (JSONObject)jRoutes.get(i)).getJSONArray("legs");
            List path = new ArrayList<>();

            for(int j=0;j<jLegs.length();j++){
                jSteps = ( (JSONObject)jLegs.get(j)).getJSONArray("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);


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

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

    return routes;
}

private List<LatLng> decodePoly(String encoded) {

    List<LatLng> poly = new ArrayList<>();
    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;
} }

在mapsActivity.java中添加了这4个方法

  private String getDirectionsUrl(LatLng origin, LatLng dest) {

    String str_origin = "origin=" + origin.latitude + "," + origin.longitude;

    String str_dest = "destination=" + dest.latitude + "," + dest.longitude;

    String sensor = "sensor=false";

    String parameters = str_origin + "&" + str_dest + "&" + sensor;

    String output = "json";

    return "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;
}

  @SuppressLint("NewApi")
  public static String downloadUrl(String strUrl) throws IOException {
    String data = "";
    HttpURLConnection urlConnection;
    URL url = new URL(strUrl);

    // Creating an http connection to communicate with url
    urlConnection = (HttpURLConnection) url.openConnection();

    // Connecting to url
    urlConnection.connect();

    // Reading data from url
    try (InputStream iStream = urlConnection.getInputStream()) {
        BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

        StringBuilder sb = new StringBuilder();

        String line;
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }

        data = sb.toString();

        br.close();

    } catch (Exception e) {
        Log.d("Exception while down", e.toString());
    } finally {
        urlConnection.disconnect();
    }
    return data;
}

  private class DownloadTask extends AsyncTask<String, Void, String> {

    // Downloading data in non-ui thread
    @Override
    protected String doInBackground(String... url) {

        // For storing data from web service
        String data = "";

        try {
            // Fetching the data from web service
            data = downloadUrl(url[0]);
        } catch (Exception e) {
            Log.d("Background Task", e.toString());
        }
        return data;
    }

    // Executes in UI thread, after the execution of
    // doInBackground()
    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);

        ParserTask parserTask = new ParserTask();

        // Invokes the thread for parsing the JSON data
        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]);
            DirectionsJSONParser parser = new DirectionsJSONParser();

            // Starts parsing data
            routes = parser.parse(jObject);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return routes;
    }

    @Override
    protected void onPostExecute(List<List<HashMap<String, String>>> result) {
        ArrayList<LatLng> points = new ArrayList<>();
        PolylineOptions lineOptions = new PolylineOptions();
        for (int i = 0; i < result.size(); i++) {
            List<HashMap<String, String>> path = result.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);
            }
            lineOptions.addAll(points);
            lineOptions.width(10);
            lineOptions.color(Color.WHITE);
            mMap.addPolyline(lineOptions);
        }
    }
}

mapsActivity.java（我在地图中的当前位置）

@Override
public void onLocationChanged(Location location) {
    Log.d("onLocationChanged", "entered");

    mLastLocation = location;

    DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
    dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date date = new Date();
    mLastUpdateTime = ((dateFormat.format(date).toString()));

    saveToFirebase();

    if (mCurrLocationMarker != null) {
        mCurrLocationMarker.remove();
    }

    latitude = location.getLatitude();
    longitude = location.getLongitude();

    LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
    MarkerOptions markerOptions = new MarkerOptions();
    markerOptions.position(latLng);
    markerOptions.draggable(false);
    markerOptions.title("Current Position");
    markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
    mCurrLocationMarker = mMap.addMarker(markerOptions);

    //move map camera
    mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
    mMap.animateCamera(CameraUpdateFactory.zoomTo(11));

    Toast.makeText(MapsActivity.this, "Your Current Location", Toast.LENGTH_LONG).show();

    //stop location updates
    if (mGoogleApiClient != null) {
     LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient,
   this);
        Log.d("onLocationChanged", "Removing Location Updates");
    }
}

Fire Base方法中保存的数据

public void saveToFirebase() {

    DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Email").push();
    String email = FirebaseAuth.getInstance().getCurrentUser().getEmail();
    UserInformation userInformation = new UserInformation(email, mLastLocation.getLatitude(), mLastLocation.getLongitude());
    ref.setValue(userInformation);
}

Answer 1

我假设你需要路线，距离和时间。首先创建这3个类。

CalculateDistanceTime.java

import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;    
import com.google.android.gms.maps.model.LatLng;    
import org.json.JSONObject;    
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 java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Set;    
class CalculateDistanceTime {    
private taskCompleteListener mTaskListener;
private Context mContext;      
CalculateDistanceTime(Context context) {
    mContext = context;
}    
void setLoadListener(taskCompleteListener taskListener) {
    mTaskListener = taskListener;
}       
void getDirectionsUrl(LatLng origin, LatLng dest) {

    // Origin of route
    String str_origin = "origin=" + origin.latitude + "," + origin.longitude;

    // Destination of route
    String str_dest = "destination=" + dest.latitude + "," + dest.longitude;


    // Sensor enabled
    String sensor = "sensor=false";

    // Building the parameters to the web service
    String parameters = str_origin + "&" + str_dest + "&" + sensor;

    // Output format
    String output = "json";

    // Building the url to the web service
    String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;


    DownloadTask downloadTask = new DownloadTask();

    // Start downloading json data from Google Directions API

    downloadTask.execute(url);
}

private String downloadUrl(String strUrl) throws IOException {
    String data = "";
    HttpURLConnection urlConnection;
    URL url = new URL(strUrl);

    // Creating an http connection to communicate with url
    urlConnection = (HttpURLConnection) url.openConnection();

    // Connecting to url
    urlConnection.connect();

    // Reading data from url
    try (InputStream iStream = urlConnection.getInputStream()) {
        BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

        StringBuilder sb = new StringBuilder();

        String line;
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }

        data = sb.toString();

        br.close();

    } catch (Exception e) {
        Log.d("Excp. while downloading", e.toString());
    } finally {
        urlConnection.disconnect();
    }
    return data;
}


interface taskCompleteListener {
    void taskCompleted(String[] time_distance);
}

private class DownloadTask extends AsyncTask<String, Void, String> {

    // Downloading data in non-ui thread
    @Override
    protected String doInBackground(String... url) {

        // For storing data from web service
        String data = "";

        try {
            // Fetching the data from web service
            data = downloadUrl(url[0]);
        } catch (Exception e) {
            Log.d("Background Task", e.toString());
        }
        return data;
    }

    // Executes in UI thread, after the execution of
    // doInBackground()
    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);

        ParserTask parserTask = new ParserTask();

        // Invokes the thread for parsing the JSON data
        parserTask.execute(result);

    }
}

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

    // Parsing the data in non-ui thread
    @Override
    protected List<HashMap<String, String>> doInBackground(String... jsonData) {

        JSONObject jObject;
        List<HashMap<String, String>> routes = null;

        try {
            jObject = new JSONObject(jsonData[0]);
            DistanceTimeParser parser = new DistanceTimeParser();

            // Starts parsing data
            routes = parser.parse(jObject);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return routes;
    }

    // Executes in UI thread, after the parsing process
    @Override
    protected void onPostExecute(List<HashMap<String, String>> result) {

        String duration_distance = "";


        if (result.size() < 1) {
            Log.e("Error : ", "No Points found");
            return;
        }


        String[] date_dist = new String[2];

        // Traversing through all the routes
        for (int i = 0; i < result.size(); i++) {

            // Fetching i-th route
            HashMap<String, String> tmpData = result.get(i);
            Set<String> key = tmpData.keySet();
            Iterator it = key.iterator();
            while (it.hasNext()) {
                String hmKey = (String) it.next();
                duration_distance = tmpData.get(hmKey);

                System.out.println("Key: " + hmKey + " & Data: " + duration_distance);

                it.remove(); // avoids a ConcurrentModificationException
            }

            date_dist[i] = duration_distance;
        }

        mTaskListener.taskCompleted(date_dist);
    }
  }
}

DistanceTimeParser.java

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class DistanceTimeParser {
    public List<HashMap<String, String>> parse(JSONObject jObject) {


    List<HashMap<String, String>> routes = new ArrayList<HashMap<String, String>>();
    JSONArray jRoutes = null;
    JSONArray jLegs = null;

    JSONObject jDistance = null;
    JSONObject jDuration = null;

    try {

        jRoutes = jObject.getJSONArray("routes");

        jLegs = ((JSONObject) jRoutes.get(0)).getJSONArray("legs");

        List<HashMap<String, String>> path = new ArrayList<HashMap<String, String>>();


        /** Getting distance from the json data */
        jDistance = ((JSONObject) jLegs.get(0)).getJSONObject("distance");
        HashMap<String, String> hmDistance = new HashMap<String, String>();
        hmDistance.put("distance", jDistance.getString("text"));

        /** Getting duration from the json data */
        jDuration = ((JSONObject) jLegs.get(0)).getJSONObject("duration");
        HashMap<String, String> hmDuration = new HashMap<String, String>();
        hmDuration.put("duration", jDuration.getString("text"));

        routes.add(hmDistance);

        routes.add(hmDuration);

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

    return routes;
}
}

DirectionsJSONParser.java

import com.google.android.gms.maps.model.LatLng;    
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;    
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
class DirectionsJSONParser {


List<List<HashMap<String,String>>> parse(JSONObject jObject){

    List<List<HashMap<String, String>>> routes = new ArrayList<>() ;
    JSONArray jRoutes ;
    JSONArray jLegs ;
    JSONArray jSteps ;

    try {

        jRoutes = jObject.getJSONArray("routes");


        for(int i=0;i<jRoutes.length();i++){
            jLegs = ( (JSONObject)jRoutes.get(i)).getJSONArray("legs");
            List path = new ArrayList<>();

            for(int j=0;j<jLegs.length();j++){
                jSteps = ( (JSONObject)jLegs.get(j)).getJSONArray("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);


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

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

    return routes;
}

private List<LatLng> decodePoly(String encoded) {

    List<LatLng> poly = new ArrayList<>();
    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;
}
}

简单地复制这三个文件后。对于任何MapsActivity，您可以执行以下操作这是您可以在任何活动中使用以下代码的点，上面的代码对于每个活动都是相同的（方向图）。

创建一个全局变量CalculateDistanceTime distance_task; 将其onCreate初始化为distance_task = new CalculateDistanceTime(this);

在MapsActivity.java中发布这4种方法。

private String getDirectionsUrl(LatLng origin, LatLng dest) {

        String str_origin = "origin=" + origin.latitude + "," + origin.longitude;


        String str_dest = "destination=" + dest.latitude + "," + dest.longitude;


        String sensor = "sensor=false";


        String parameters = str_origin + "&" + str_dest + "&" + sensor;

        String output = "json";


        return "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;
    }

    public static String downloadUrl(String strUrl) throws IOException {
        String data = "";
        HttpURLConnection urlConnection;
        URL url = new URL(strUrl);

        // Creating an http connection to communicate with url
        urlConnection = (HttpURLConnection) url.openConnection();

        // Connecting to url
        urlConnection.connect();

        // Reading data from url
        try (InputStream iStream = urlConnection.getInputStream()) {
            BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

            StringBuilder sb = new StringBuilder();

            String line;
            while ((line = br.readLine()) != null) {
                sb.append(line);
            }

            data = sb.toString();

            br.close();

        } catch (Exception e) {
            Log.d("Exception while down", e.toString());
        } finally {
            urlConnection.disconnect();
        }
        return data;
    }

private class DownloadTask extends AsyncTask<String, Void, String> {

        // Downloading data in non-ui thread
        @Override
        protected String doInBackground(String... url) {

            // For storing data from web service
            String data = "";

            try {
                // Fetching the data from web service
                data = downloadUrl(url[0]);
            } catch (Exception e) {
                Log.d("Background Task", e.toString());
            }
            return data;
        }

        // Executes in UI thread, after the execution of
        // doInBackground()
        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);

            ParserTask parserTask = new ParserTask();

            // Invokes the thread for parsing the JSON data
            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]);
                DirectionsJSONParser parser = new DirectionsJSONParser();

                // Starts parsing data
                routes = parser.parse(jObject);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return routes;
        }

        @Override
        protected void onPostExecute(List<List<HashMap<String, String>>> result) {
            ArrayList<LatLng> points = new ArrayList<>();
            lineOptions = new PolylineOptions();
            for (int i = 0; i < result.size(); i++) {
                List<HashMap<String, String>> path = result.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);
                }
                lineOptions.addAll(points);
                lineOptions.width(10);                   
                lineOptions.color(Color.WHITE);
                googleMap.addPolyline(lineOptions);                
        }
    }

此时您已获得所有必需的代码现在使用以下代码传递您所在位置和朋友位置的latlng，您将拥有时间距离和路线。

               distance_task.getDirectionsUrl(latLng1, latLng2);
               distance_task.setLoadListener(new CalculateDistanceTime.taskCompleteListener() {
                        @Override
                        public void taskCompleted(String[] time_distance) {
                            text1.setText(time_distance[0]); //Distance
                            text2.setText(time_distance[1]); //Time
                        }
                    });
               String url = getDirectionsUrl(latLng1, latLng2);
               DownloadTask downloadTask = new DownloadTask();
               downloadTask.execute(url);

要显示距离和时间，您必须创建两个TextView（请参阅上面的text1和Text2）。

Answer 2

添加以下代码并替换为您的绘图折线代码，使用此

 String url = getUrl(origin, dest);
 FetchUrl FetchUrl = new FetchUrl();

 // Start downloading json data from Google Directions API
FetchUrl.execute(url);

使用上面的代码来绘制路线origin＆amp; dest是LatLng对象，例如下面的

LatLng dest = new LatLng(Double.parseDouble(d_lat), Double.parseDouble(d_lng));

以下是获取路线的方法，

private String getUrl(LatLng origin, LatLng dest) {

        // Origin of route
        String str_origin = "origin=" + origin.latitude + "," + origin.longitude;

        // Destination of route
        String str_dest = "destination=" + dest.latitude + "," + dest.longitude;


        // Sensor enabled
        String sensor = "sensor=false";

        // Building the parameters to the web service
        String parameters = str_origin + "&" + str_dest + "&" + sensor;

        // Output format
        String output = "json";

        // Building the url to the web service


        return "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;
    }

在此之后使用以下类，

private class FetchUrl extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... url) {

            // For storing data from web service
            String data = "";

            try {
                // Fetching the data from web service
                data = downloadUrl(url[0]);
                Log.d("Background Task data", data);
            } catch (Exception e) {
                Log.d("Background Task", e.toString());
            }
            return data;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);

            ParserTask parserTask = new ParserTask();

            // Invokes the thread for parsing the JSON data
            parserTask.execute(result);

        }
    }

    /**
     * A class to parse the Google Places in JSON format
     */

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

        // Parsing the data in non-ui thread
        @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]);

                Log.d("ParserTask", jsonData[0]);

                JSONArray array = jObject.getJSONArray("routes");
                JSONObject paths = array.getJSONObject(0);
                JSONArray legs = paths.getJSONArray("legs");
                JSONObject steps = legs.getJSONObject(0);
                JSONObject distance = steps.getJSONObject("distance");
                JSONObject duration = legs.getJSONObject(0).getJSONObject("duration");
                parsedDistance = distance.getString("text");
                if (parsedDistance.contains("km")) {
                    String[] val = parsedDistance.split(" ");
                    String val1 = val[0];
                    distance_from = convertInMiles(val1);
                } else {
                    distance_from = parsedDistance;
                }
                address = legs.getJSONObject(0).getString("end_address");
                time = duration.getString("text");
                DataParser parser = new DataParser();
                Log.d("ParserTask", parser.toString());

                // Starts parsing data
                routes = parser.parse(jObject);
                Log.d("ParserTask", "Executing routes");
                Log.d("ParserTask", routes.toString());

            } catch (Exception e) {
                Log.d("ParserTask", e.toString());
                e.printStackTrace();
            }
            return routes;
        }

        // Executes in UI thread, after the parsing process
        @Override
        protected void onPostExecute(List<List<HashMap<String, String>>> result) {
            ArrayList<LatLng> points;
            PolylineOptions lineOptions = null;

            // Traversing through all the routes
            if (result != null && result.size() > 0) {
                for (int i = 0; i < result.size(); i++) {
                    points = new ArrayList<>();
                    lineOptions = new PolylineOptions();

                    // Fetching i-th route
                    List<HashMap<String, String>> path = result.get(i);

                    // Fetching all the points in i-th route
                    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);
                    }

                    // Adding all the points in the route to LineOptions
                    lineOptions.addAll(points);
                    lineOptions.width(10);
                    lineOptions.color(Color.BLACK);

                    p_distance.setText("Distance : " + distance_from);
                    p_time.setText("ETA :" + time);
                    if (p_time.getText().toString().length() == 10) {
                        arrival_time = p_time.getText().toString().substring(5, p_time.getText().toString().length() - 4);
                        Log.d("arrival_time", arrival_time);
                        SessionManager.put(Constants.TIME, arrival_time);
                    } else if (p_time.getText().toString().length() > 10) {
                        arrival_time = p_time.getText().toString().substring(5, p_time.getText().toString().length() - 5);
                        Log.d("arrival_time", arrival_time);
                        SessionManager.put(Constants.TIME, arrival_time);
                    }
                    p_address.setText("Address : " + address);
                    navigation.setVisibility(View.VISIBLE);
                    Log.d("onPostExecute", "onPostExecute lineoptions decoded");
                }

            }

            // Drawing polyline in the Google Map for the i-th route
            if (lineOptions != null) {
                mMap.addPolyline(lineOptions);
            } else {
                Log.d("onPostExecute", "without Polylines drawn");
            }
        }
    }

private String downloadUrl(String strUrl) throws IOException {
        String data = "";
        InputStream iStream = null;
        HttpURLConnection urlConnection = null;
        try {
            URL url = new URL(strUrl);

            // Creating an http connection to communicate with url
            urlConnection = (HttpURLConnection) url.openConnection();

            // Connecting to url
            urlConnection.connect();

            // Reading data from url
            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();
            Log.d("downloadUrl", data);
            br.close();

        } catch (Exception e) {
            Log.d("Exception", e.toString());
        } finally {
            assert iStream != null;
            iStream.close();
            assert urlConnection != null;
            urlConnection.disconnect();
        }
        return data;
    }

折线不显示在2个位置之间，但显示时间和距离

2 个答案: