android - 在 Android 上的 Google Maps API v2 中显示路线

Question

我试图在 Android 中显示两个 MarkerOptions 点之间的行车路线。我找到了 this tutorial here ，这对我来说效果很好，但我正在尝试对其进行调整，以便 MarkerOptions 是我当前的位置和一个固定的 LatLng 对象，而不是当您获得两点时触摸 map 。所以我得到了我当前的位置，LatLng = updatedLatLng，固定位置是 LatLng = wcbcLatLng。在本教程中，onMapClick 方法如下所示:

    public void onTouchMap(){

    // Setting onclick event listener for the map
    this.mapG3.setOnMapClickListener(new OnMapClickListener() {
        @Override
        public void onMapClick(LatLng point) {
            // Already two locations
            if (Geo4.this.markerPoints.size() > 1) {
                Geo4.this.markerPoints.clear();
                Geo4.this.mapG3.clear();
            }

            // Adding new item to the ArrayList
            Geo4.this.markerPoints.add(point);

            // Creating MarkerOptions
            MarkerOptions options = new MarkerOptions();

            // Setting the position of the marker
            options.position(point);

            /**
             * For the start location, the color of marker is GREEN and for
             * the end location, the color of marker is RED.
             */
            if (Geo4.this.markerPoints.size() == 1) {
                options.icon(BitmapDescriptorFactory
                        .defaultMarker

(BitmapDescriptorFactory.HUE_GREEN));
            } else if (Geo4.this.markerPoints.size() == 2) {
                options.icon(BitmapDescriptorFactory
                        .defaultMarker

(BitmapDescriptorFactory.HUE_RED));
            }

            // Add new marker to the Google Map Android API V2
            Geo4.this.mapG3.addMarker(options);

            // Checks, whether start and end locations are captured
            if (Geo4.this.markerPoints.size() >= 2) {
                LatLng origin = Geo4.this.markerPoints.get(0);
                LatLng dest = Geo4.this.markerPoints.get(1);

                // Getting URL to the Google Directions API
                String url = Geo4.this.getDirectionsUrl(origin, dest);

                DownloadTask downloadTask = new DownloadTask();

                // Start downloading json data from Google Directions API
                downloadTask.execute(url);
            }
        }
    });
}//-- END Method

这是我要修改的方法，以便它查找我的 updatedLatLng & wcbcLatLng 而不是 LatLng origin & LatLng dest 该方法当前正在使用。任何帮助，将不胜感激!这是我的完整 Activity :

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

import org.json.JSONObject;

import android.app.AlertDialog;
import android.content.Intent;
import android.graphics.Color;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;
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.LatLngBounds;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;

import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.provider.Settings;

public class Geo4 extends FragmentActivity implements LocationListener {
GoogleMap mapG3;
ArrayList<LatLng> markerPoints;
TextView mapInfo_TV;
LocationManager locMan;
SupportMapFragment sMf;
Button back_btn, zoom_btn;
MarkerOptions startMO, wcbcMO, broncoMO;
MarkerOptions markers;
Marker currentMarker, wcbcMarker, broncoMarker;
LatLng updatedLatLng, directionsLatLng;
LatLng wcbcLatLng = new LatLng(30.393903, -97.682871);
LatLng oskiLatLng = new LatLng(30.474570, -97.973889);
LatLng point, point3t, point4t;
CameraUpdate cameraUpdate;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.geo3);
    back_btn = (Button) findViewById(R.id.backMap_g3_btn);
    zoom_btn = (Button) findViewById(R.id.marker_g3_btn);

    this.mapInfo_TV = (TextView) this.findViewById(R.id.map_g3Info_TV);
    // Initializing
    this.markerPoints = new ArrayList<LatLng>();

    // Getting reference to SupportMapFragment of the activity_main
    sMf = (SupportMapFragment) this.getSupportFragmentManager()
            .findFragmentById(R.id.map_g3_FRAG);

    // Getting Map for the SupportMapFragment
    this.mapG3 = sMf.getMap();

    // --- fire Methods
    googlePlay();
    getCurrentLocation();
    onTouchMap();

    // --- END fire Methods

    // --- Back button
    back_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View arg0) {
            // mapG3.clear();
            Intent backmapI = new Intent(
                    "com.my.package.BUTTON_INTERFACE");
            startActivity(backmapI);

        }
    });
    // --- end Back button

    // --- Zoom button
    zoom_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View arg0) {
            getDirections4T(point4t);
        }
    });
    // --- end Zoom button

}// --- END onCreate

// --- Methods ----

public void googlePlay() {
    // ---- Google Play

    // Getting Google Play availability status
    int status = GooglePlayServicesUtil
            .isGooglePlayServicesAvailable(getBaseContext());

    if (status != ConnectionResult.SUCCESS) { // Google Play Services are
                                                    // not available

        int requestCode = 10;
        Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this,
                requestCode);
        dialog.show();

    } else { // Google Play Services are available

        //Toast.makeText(getApplicationContext(),"Services Launched Fo  Sho'",Toast.LENGTH_SHORT).show();
    }
}

// ---- END Method

public void getCurrentLocation(){
    // Getting LocationManager object from System Service LOCATION_SERVICE
    locMan = (LocationManager) getSystemService(LOCATION_SERVICE);
    boolean enabledGPS = locMan
            .isProviderEnabled(LocationManager.GPS_PROVIDER);
    boolean enabledWiFi = locMan
            .isProviderEnabled(LocationManager.NETWORK_PROVIDER);
    // Check if enabled and if not send user to the GPS settings
    if (!enabledGPS && !enabledWiFi) {
        Toast.makeText(getApplicationContext(), "GPS signal not found",
                Toast.LENGTH_LONG).show();
        Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
        startActivity(intent);
    }
    // Creating a criteria object to retrieve provider
    Criteria criteria = new Criteria();

    // Getting the name of the best provider
    String provider = locMan.getBestProvider(criteria, true);

    // Getting Current Location From GPS
    Location oLc = locMan.getLastKnownLocation(provider);
    if (oLc != null) {
        onLocationChanged(oLc);
    }
    locMan.requestLocationUpdates(provider, 20000, 0, this);

}//--- END Method

public void zoomToFit() {
    // --- zoom to fit
    LatLngBounds.Builder builder = new LatLngBounds.Builder();
    builder.include(wcbcLatLng);
    builder.include(updatedLatLng);
    LatLngBounds bounds = builder.build();
    int padding = 50; // offset from edges of the map in pixels
    cameraUpdate = CameraUpdateFactory.newLatLngBounds(bounds, padding);
    mapG3.animateCamera(cameraUpdate);
    // --- END zoom to fit

}// --- END Method

public void addwcbcMarkerOption() {
    wcbcMO = new MarkerOptions().position(wcbcLatLng).title(
    "Destination");
    wcbcMO.icon(BitmapDescriptorFactory
            .defaultMarker(BitmapDescriptorFactory.HUE_VIOLET));
    mapG3.addMarker(wcbcMO);
    cameraUpdate = CameraUpdateFactory.newLatLngZoom(wcbcLatLng, 15);
    mapG3.animateCamera(cameraUpdate);
}// --- END Method

public void getDirections4T(LatLng point4t) {


    Geo4.this.markerPoints.add(point4t);
    markers = new MarkerOptions();
    markers.position(wcbcLatLng);
    markers.position(oskiLatLng);

    if (Geo4.this.markerPoints.size() == 1) {
        markers.icon(BitmapDescriptorFactory
                .defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
    } else if (Geo4.this.markerPoints.size() == 2) {
        markers.icon(BitmapDescriptorFactory
                .defaultMarker(BitmapDescriptorFactory.HUE_RED));
    }
    Geo4.this.mapG3.addMarker(markers);


}//--- END Method

public void onTouchMap(){

    // Setting onclick event listener for the map
    this.mapG3.setOnMapClickListener(new OnMapClickListener() {
        @Override
        public void onMapClick(LatLng point) {
            // Already two locations
            if (Geo4.this.markerPoints.size() > 1) {
                Geo4.this.markerPoints.clear();
                Geo4.this.mapG3.clear();
            }

            // Adding new item to the ArrayList
            Geo4.this.markerPoints.add(point);

            // Creating MarkerOptions
            MarkerOptions options = new MarkerOptions();

            // Setting the position of the marker
            options.position(point);

            /**
             * For the start location, the color of marker is GREEN and for
             * the end location, the color of marker is RED.
             */
            if (Geo4.this.markerPoints.size() == 1) {
                options.icon(BitmapDescriptorFactory
                        .defaultMarker

(BitmapDescriptorFactory.HUE_GREEN));
            } else if (Geo4.this.markerPoints.size() == 2) {
                options.icon(BitmapDescriptorFactory
                        .defaultMarker

(BitmapDescriptorFactory.HUE_RED));
            }

            // Add new marker to the Google Map Android API V2
            Geo4.this.mapG3.addMarker(options);

            // Checks, whether start and end locations are captured
            if (Geo4.this.markerPoints.size() >= 2) {
                LatLng origin = Geo4.this.markerPoints.get(0);
                LatLng dest = Geo4.this.markerPoints.get(1);

                // Getting URL to the Google Directions API
                String url = Geo4.this.getDirectionsUrl(origin, dest);

                DownloadTask downloadTask = new DownloadTask();

                // Start downloading json data from Google Directions API
                downloadTask.execute(url);
            }
        }
    });
}//-- END Method

private String getDirectionsUrl(LatLng updatedLatLng, LatLng dest) {
    // Origin of route
    String str_updatedLatLng = "origin=" + updatedLatLng.latitude + ","
            + updatedLatLng.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_updatedLatLng + "&" + 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;

    return url;
}

/** A method to download json data from url */
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();

        br.close();

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

// Fetches data from url passed
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 = Geo4.this.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);

    }
}

/** 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]);
            Geo3JSON parser = new Geo3JSON();

            // 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<List<HashMap<String, String>>> result) {
        ArrayList<LatLng> points = null;
        PolylineOptions lineOptions = null;
        MarkerOptions markerOptions = new MarkerOptions();
        String distance = "";
        String duration = "";

        if (result.size() < 1) {
            Toast.makeText(Geo4.this.getBaseContext(), "No Points",
                    Toast.LENGTH_SHORT).show();
            return;
        }

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

                if (j == 0) { // Get distance from the list
                    distance = point.get("distance");
                    continue;
                } else if (j == 1) { // Get duration from the list
                    duration = point.get("duration");
                    continue;
                }
                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(4);
            lineOptions.color(Color.RED);
        }

        Geo4.this.mapInfo_TV.setText("Distance: " + distance + "les");

        // Drawing polyline in the Google Map for the route
        Geo4.this.mapG3.addPolyline(lineOptions);
    }
}

// --- END Methods

// --- onLocationListener

@Override
public void onLocationChanged(Location oLc) {

    updatedLatLng = new LatLng(oLc.getLatitude(), oLc.getLongitude());

    startMO = new MarkerOptions().position(updatedLatLng)
    .title("You Are Here")
    .icon(BitmapDescriptorFactory
            .defaultMarker(BitmapDescriptorFactory.HUE_ORANGE));
    mapG3.addMarker(startMO);

    addwcbcMarkerOption();

    locMan.removeUpdates(this);

}

@Override
public void onProviderDisabled(String provider) {
    //

}

@Override
public void onProviderEnabled(String provider) {
    //

}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
    //

}

// --- END onLocationListener

@Override
protected void onPause() {
    super.onPause();
    overridePendingTransition(R.anim.fadein, R.anim.fadeout);
    finish();
}

// --- inflated menu
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.wcbcv, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.menu_legalnotices:
        String LicenseInfo = GooglePlayServicesUtil
                .getOpenSourceSoftwareLicenseInfo(getApplicationContext

());
        AlertDialog.Builder LicenseDialog = new AlertDialog.Builder(
                Geo4.this);
        LicenseDialog.setTitle("Legal Notices");
        LicenseDialog.setMessage(LicenseInfo);
        LicenseDialog.show();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

// --- END inflated menu
}

Answer 1

我想通了。我的大部分 onTouchMap() 都在获取 onTouch 信息并将这些整数转换为 LatLng 值。因为我已经有了 LatLng 值，所以我只需要采用 LatLng 并从中获取 JSON 数据的方法的最后三行.所以我重写了方法以首先添加 MarkerOptions 和 LatLng 值，然后我添加了旧方法的最后 3 行。这就是我的新方法的样子，它可以正常工作(通过调用其他 3 个方法)并绘制折线并在 TextView 中显示以英里为单位的距离。

    public void addMarkers(){
    wcbcMO = new MarkerOptions().position(wcbcLatLng)
    .title("Destination")
    .icon(BitmapDescriptorFactory
            .defaultMarker(BitmapDescriptorFactory.HUE_VIOLET));
    mapG3.addMarker(wcbcMO);

    startMO = new MarkerOptions().position(updatedLatLng)
    .title("You Are Here")
    .icon(BitmapDescriptorFactory
            .defaultMarker(BitmapDescriptorFactory.HUE_ORANGE));
    mapG3.addMarker(startMO);

    // Getting URL to the Google Directions API
    String url = Geo4.this.getDirectionsUrl(updatedLatLng, wcbcLatLng);

    DownloadTask downloadTask = new DownloadTask();

    // Start downloading json data from Google Directions API
    downloadTask.execute(url);
}//--- END Method