標記未顯示在谷歌地圖中的兩個標記之間選擇和定位以計算並繪製兩個標記之間的路徑

Question

標記不顯示在谷歌地圖中的兩個標記之間選擇和定位以計算和繪製路徑。

我想用標記選擇兩個位置並計算距離並在選擇後在兩個標記之間繪製一條路徑。但無法用標記選擇兩個位置並且無法計算距離。

我無法從具有標記的位置設置，設置爲具有標記的位置，也無法計算距離。

MapsActivity.java

public class MapsActivity extends FragmentActivity implements 
     OnMapReadyCallback, 
     GoogleApiClient.ConnectionCallbacks, 
     GoogleApiClient.OnConnectionFailedListener, 
     GoogleMap.OnMarkerDragListener, 
     GoogleMap.OnMapLongClickListener, 
     View.OnClickListener{ 

    //Our Map 
    private GoogleMap mMap; 

    //To store longitude and latitude from map 
    private double longitude; 
    private double latitude; 

    //From -> the first coordinate from where we need to calculate the distance 
    private double fromLongitude; 
    private double fromLatitude; 

    //To -> the second coordinate to where we need to calculate the distance 
    private double toLongitude; 
    private double toLatitude; 

    //Google ApiClient 
    private GoogleApiClient googleApiClient; 

    //Our buttons 
    private Button buttonSetTo; 
    private Button buttonSetFrom; 
    private Button buttonCalcDistance; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_maps); 
     // Obtain the SupportMapFragment and get notified when the map is ready to be used. 
     SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() 
       .findFragmentById(R.id.map); 
     mapFragment.getMapAsync(this); 

     //Initializing googleapi client 
     // ATTENTION: This "addApi(AppIndex.API)"was auto-generated to implement the App Indexing API. 
     // See https://g.co/AppIndexing/AndroidStudio for more information. 
     googleApiClient = new GoogleApiClient.Builder(this) 
       .addConnectionCallbacks(this) 
       .addOnConnectionFailedListener(this) 
       .addApi(LocationServices.API) 
       .addApi(AppIndex.API).build(); 

     buttonSetTo = (Button) findViewById(R.id.buttonSetTo); 
     buttonSetFrom = (Button) findViewById(R.id.buttonSetFrom); 
     buttonCalcDistance = (Button) findViewById(R.id.buttonCalcDistance); 

     buttonSetTo.setOnClickListener(this); 
     buttonSetFrom.setOnClickListener(this); 
     buttonCalcDistance.setOnClickListener(this); 
    } 

    @Override 
    protected void onStart() { 
     googleApiClient.connect(); 
     super.onStart(); 
     // ATTENTION: This was auto-generated to implement the App Indexing API. 
     // See https://g.co/AppIndexing/AndroidStudio for more information. 
     Action viewAction = Action.newAction(
       Action.TYPE_VIEW, // TODO: choose an action type. 
       "Maps Page", // TODO: Define a title for the content shown. 
       // TODO: If you have web page content that matches this app activity's content, 
       // make sure this auto-generated web page URL is correct. 
       // Otherwise, set the URL to null. 
       Uri.parse("http://host/path"), 
       // TODO: Make sure this auto-generated app deep link URI is correct. 
       Uri.parse("android-app://net.simplifiedcoding.googlemapsdistancecalc/http/host/path") 
     ); 
     AppIndex.AppIndexApi.start(googleApiClient, viewAction); 
    } 

    @Override 
    protected void onStop() { 
     googleApiClient.disconnect(); 
     super.onStop(); 
     // ATTENTION: This was auto-generated to implement the App Indexing API. 
     // See https://g.co/AppIndexing/AndroidStudio for more information. 
     Action viewAction = Action.newAction(
       Action.TYPE_VIEW, // TODO: choose an action type. 
       "Maps Page", // TODO: Define a title for the content shown. 
       // TODO: If you have web page content that matches this app activity's content, 
       // make sure this auto-generated web page URL is correct. 
       // Otherwise, set the URL to null. 
       Uri.parse("http://host/path"), 
       // TODO: Make sure this auto-generated app deep link URI is correct. 
       Uri.parse("android-app://net.simplifiedcoding.googlemapsdistancecalc/http/host/path") 
     ); 
     AppIndex.AppIndexApi.end(googleApiClient, viewAction); 
    } 

    //Getting current location 
    private void getCurrentLocation() { 
     mMap.clear(); 
     //Creating a location object 
     Location location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient); 
     if (location != null) { 
      //Getting longitude and latitude 
      longitude = location.getLongitude(); 
      latitude = location.getLatitude(); 

      //moving the map to location 
      moveMap(); 
     } 
    } 

    //Function to move the map 
    private void moveMap() { 
     //Creating a LatLng Object to store Coordinates 
     LatLng latLng = new LatLng(latitude, longitude); 

     //Adding marker to map 
     mMap.addMarker(new MarkerOptions() 
       .position(latLng) //setting position 
       .draggable(true) //Making the marker draggable 
       .title("Current Location")); //Adding a title 

     //Moving the camera 
     mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng)); 

     //Animating the camera 
     mMap.animateCamera(CameraUpdateFactory.zoomTo(15)); 
    } 

    public String makeURL (double sourcelat, double sourcelog, double destlat, double destlog){ 
     StringBuilder urlString = new StringBuilder(); 
     urlString.append("https://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"); 
     urlString.append("&key=AIzaSyB2iWnsp0TvWCrBB5AYYxG8J3Mad4q1npo"); 
     return urlString.toString(); 
    } 

    private void getDirection(){ 
     //Getting the URL 
     String url = makeURL(fromLatitude, fromLongitude, toLatitude, toLongitude); 

     //Showing a dialog till we get the route 
     final ProgressDialog loading = ProgressDialog.show(this, "Getting Route", "Please wait...", false, false); 

     //Creating a string request 
     StringRequest stringRequest = new StringRequest(url, 
       new Response.Listener<String>() { 
        @Override 
        public void onResponse(String response) { 
         loading.dismiss(); 
         //Calling the method drawPath to draw the path 
         drawPath(response); 
        } 
       }, 
       new Response.ErrorListener() { 
        @Override 
        public void onErrorResponse(VolleyError error) { 
         loading.dismiss(); 
        } 
       }); 

     //Adding the request to request queue 
     RequestQueue requestQueue = Volley.newRequestQueue(this); 
     requestQueue.add(stringRequest); 
    } 

    //The parameter is the server response 
    public void drawPath(String result) { 
     //Getting both the coordinates 
     LatLng from = new LatLng(fromLatitude,fromLongitude); 
     LatLng to = new LatLng(toLatitude,toLongitude); 

     //Calculating the distance in meters 
     Double distance = SphericalUtil.computeDistanceBetween(from, to); 

     //Displaying the distance 
     Toast.makeText(this,String.valueOf(distance+" Meters"),Toast.LENGTH_SHORT).show(); 


     try { 
      //Parsing json 
      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); 
      Polyline line = mMap.addPolyline(new PolylineOptions() 
          .addAll(list) 
          .width(20) 
          .color(Color.RED) 
          .geodesic(true) 
      ); 


     } 
     catch (JSONException e) { 

     } 
    } 

    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; 
    } 

    @Override 
    public void onMapReady(GoogleMap googleMap) { 
     mMap = googleMap; 
     LatLng latLng = new LatLng(-34, 151); 
     mMap.addMarker(new MarkerOptions().position(latLng).draggable(true)); 
     mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng)); 
     mMap.setOnMarkerDragListener(this); 
     mMap.setOnMapLongClickListener(this); 
    } 

    @Override 
    public void onConnected(Bundle bundle) { 
     getCurrentLocation(); 
    } 

    @Override 
    public void onConnectionSuspended(int i) { 

    } 

    @Override 
    public void onConnectionFailed(ConnectionResult connectionResult) { 

    } 

    @Override 
    public void onMapLongClick(LatLng latLng) { 
     //Clearing all the markers 
     mMap.clear(); 
     //Adding a new marker to the current pressed position 
     mMap.addMarker(new MarkerOptions() 
       .position(latLng) 
       .draggable(true)); 

     latitude = latLng.latitude; 
     longitude = latLng.longitude; 
    } 

    @Override 
    public void onMarkerDragStart(Marker marker) { 

    } 

    @Override 
    public void onMarkerDrag(Marker marker) { 

    } 

    @Override 
    public void onMarkerDragEnd(Marker marker) { 
     //Getting the coordinates 
     latitude = marker.getPosition().latitude; 
     longitude = marker.getPosition().longitude; 

     //Moving the map 
     moveMap(); 
    } 

    @Override 
    public void onClick(View v) { 
     if(v == buttonSetFrom){ 
      fromLatitude = latitude; 
      fromLongitude = longitude; 
      Toast.makeText(this,"From set",Toast.LENGTH_SHORT).show(); 
     } 

     if(v == buttonSetTo){ 
      toLatitude = latitude; 
      toLongitude = longitude; 
      Toast.makeText(this,"To set",Toast.LENGTH_SHORT).show(); 
     } 

     if(v == buttonCalcDistance){ 
      getDirection(); 
     } 
    } 
} 

activity_maps.xml

<FrameLayout 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=".MapsActivity"> 

    <fragment xmlns:android="http://schemas.android.com/apk/res/android" 
     xmlns:map="http://schemas.android.com/apk/res-auto" 
     xmlns:tools="http://schemas.android.com/tools" 
     android:id="@+id/map" 
     android:name="com.google.android.gms.maps.SupportMapFragment" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     tools:context="net.simplifiedcoding.mymapapp.MapsActivity" /> 

    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:gravity="bottom" 
     android:orientation="vertical"> 

     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:background="#cc3b60a7" 
      android:orientation="horizontal"> 

      <Button 
       android:id="@+id/buttonSetFrom" 
       android:text="Set From" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" /> 

      <Button 
       android:id="@+id/buttonSetTo" 
       android:text="Set To" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" /> 


      <Button 
       android:id="@+id/buttonCalcDistance" 
       android:text="Calc Distance" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" /> 


     </LinearLayout> 
    </LinearLayout> 
</FrameLayout> 

Answer 1

要做兩個起源和dest之間的代碼取管線：

@Override 
    public void onMapReady(GoogleMap googleMap) { 
     mMap = googleMap; 
     // Add a marker in Sydney and move the camera 
     LatLng sydney = new LatLng(latitude, longitude); 
     mMap.clear(); 
     CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(latitude, longitude), 16); 
     mMap.animateCamera(cameraUpdate); 
     System.out.println("Latitude "+latitude+ " \n Longitude "+longitude); 
     mMap.setMyLocationEnabled(true); 

     LatLng origin = new LatLng(latitude,longitude); 
     LatLng dest = new LatLng(Double.parseDouble(destLatitude),Double.parseDouble(destLongitude)); 

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

     DownloadTask downloadTask = new DownloadTask(); 

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


    } 

private String 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; 

     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 downloading", 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 = 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]); 
       DirectionsJSONParser parser = new DirectionsJSONParser(); 

       // 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(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 = (String)point.get("distance"); 
         continue; 
        }else if(j==1){ // Get duration from the list 
         duration = (String)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(5); 
       lineOptions.color(Color.RED); 
      } 

      tvDistanceDuration.setText("Distance:"+distance + ", Duration:"+duration); 

      // Drawing polyline in the Google Map for the i-th route 
      mMap.addPolyline(lineOptions); 
      mMap.addMarker(new MarkerOptions() 
        .position(new LatLng(Double.parseDouble(destLatitude), Double.parseDouble(destLongitude))) 
       .title(getLocationStringAddress(new LatLng(Double.parseDouble(destLatitude), Double.parseDouble(destLongitude)))) 
//     .snippet(getLocationStringAddress(new LatLng(Double.parseDouble(destLatitude), Double.parseDouble(destLongitude)))) 
        .icon(BitmapDescriptorFactory.fromResource(R.mipmap.map_set_marker))); 
     } 
    }