我想在我当前的位置和标记之间建立一条路线，不确定如何关注。我在地图上添加了一个标记，但它没有显示折线。例如，当用户启动应用程序时，他们应该获得从他们的位置到标记的路线。我真的堆叠在此。
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener,
LocationListener {
private GoogleMap mMap;
ArrayList < LatLng > MarkerPoints;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
LocationRequest mLocationRequest;
@
Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
// Initializing
MarkerPoints = new ArrayList < > ();
// 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);
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@
Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
//Initialize Google Play Services
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
} else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
mMap.addMarker(new MarkerOptions().position(new LatLng(34.701466, 33.029269)).title("UMAR"));
// Already two locations
if (MarkerPoints.size() > 1) {
MarkerPoints.clear();
mMap.clear();
}
}
// Setting onclick event listener for the map
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
@
Override
public void onMapClick(LatLng point) {
// Adding new item to the ArrayList
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 (MarkerPoints.size() == 1) {
options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
} else if (MarkerPoints.size() == 2) {
options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
}
// Checks, whether start and end locations are captured
if (MarkerPoints.size() >= 2) {
LatLng origin = MarkerPoints.get(0);
LatLng dest = MarkerPoints.get(1);
// Getting URL to the Google Directions API
String url = getUrl(origin, dest);
Log.d("onMapClick", url.toString());
FetchUrl FetchUrl = new FetchUrl();
// Start downloading json data from Google Directions API
FetchUrl.execute(url);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(origin));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
}
}
});
}
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
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();
Log.d("downloadUrl", data.toString());
br.close();
} catch (Exception e) {
Log.d("Exception", e.toString());
} finally {
iStream.close();
urlConnection.disconnect();
}
return data;
}
// Fetches data from url passed
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.toString());
} 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].toString());
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
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.RED);
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");
}
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
@
Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
@
Override
public void onConnectionSuspended(int i) {
}
@
Override
public void onLocationChanged(Location location) {
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
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));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
@
Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
public boolean checkLocationPermission() {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// Asking user if explanation is needed
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(this,
new String[] {
Manifest.permission.ACCESS_FINE_LOCATION
},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[] {
Manifest.permission.ACCESS_FINE_LOCATION
},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
@
Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION:
{
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted. Do the
// contacts-related task you need to do.
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
// Permission denied, Disable the functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
}
}
}