java – PolyLine不在路上：它从一个点直接到另一个点
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互联网集市收集整理的这篇技术教程文章主要介绍了java – PolyLine不在路上：它从一个点直接到另一个点，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含6352字，纯文字阅读大概需要10分钟。
内容图文
我的地图包含多个点来点击用户所在位置,但是the polyline is not shown on the roads, but shows a direct line from one marker to other.我希望我的折线穿过马路：当道路转弯时,它也应该转弯.
这是我的相关代码
dataholder = FirebaseDatabase.getInstance().getReference("UserLocation");
Log.d("onMapReady", "iam here");
dataholder.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.d("data",String.valueOf(dataSnapshot.getValue()));
System.out.println(dataSnapshot.getValue());
for (DataSnapshot a : dataSnapshot.getChildren()) {
MapData mapData = a.getValue(MapData.class);
arrayList.add(mapData);
lati.add(arrayList.get(i).getLatituide());
longit.add(arrayList.get(i).getLongitude());
Log.d("mapi","i am in loop");
mMap = googleMap;
Double lat = Double.parseDouble(lati.get(i));
Double longi = Double.parseDouble(longit.get(i));
sydney = new LatLng(longi, lat);
points.add(sydney);
MarkerOptions mop = new MarkerOptions();
mop.position(sydney);
mop.title("check");
mMap.addMarker(mop);
Log.d("latitude", String.valueOf(lat));
Log.d("longitude", String.valueOf(longi));
// Add a marker in Sydney and move the camera
mMap.addMarker(new MarkerOptions().position(sydney).title("check"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
i++;
}
line.addAll(points).width(5).color(Color.RED);
line.geodesic(true);
mMap.addPolyline(line);
mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
@Override
public boolean onMarkerClick(Marker marker) {
Toast.makeText(getApplicationContext(),marker.getTitle().toString(),Toast.LENGTH_LONG).show();
return false;
}
});
解决方法:
尝试使用Google Maps Roads API Snap to Road部分
returns the best-fit road geometry for a given set of GPS coordinates.
This service takes up to 100 GPS points collected along a route, and
returns a similar set of data with the points snapped to the most
likely roads the vehicle was traveling along.
类似于Google Maps Roads API Snap to Road示例中的数据：
public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
private GoogleMap mGoogleMap;
private MapFragment mapFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mapFragment = (MapFragment) getFragmentManager()
.findFragmentById(R.id.map_fragment);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mGoogleMap = googleMap;
List<LatLng> sourcePoints = new ArrayList<>();
sourcePoints.add(new LatLng(-35.27801,149.12958));
sourcePoints.add(new LatLng(-35.28032,149.12907));
sourcePoints.add(new LatLng(-35.28099,149.12929));
sourcePoints.add(new LatLng(-35.28144,149.12984));
sourcePoints.add(new LatLng(-35.28194,149.13003));
sourcePoints.add(new LatLng(-35.28282,149.12956));
sourcePoints.add(new LatLng(-35.28302,149.12881));
sourcePoints.add(new LatLng(-35.28473,149.12836));
PolylineOptions polyLineOptions = new PolylineOptions();
polyLineOptions.addAll(sourcePoints);
polyLineOptions.width(5);
polyLineOptions.color(Color.BLUE);
mGoogleMap.addPolyline(polyLineOptions);
mGoogleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(sourcePoints.get(0), 15));
List<LatLng> snappedPoints = new ArrayList<>();
new GetSnappedPointsAsyncTask().execute(sourcePoints, null, snappedPoints);
}
private String buildRequestUrl(List<LatLng> trackPoints) {
StringBuilder url = new StringBuilder();
url.append("https://roads.googleapis.com/v1/snapToRoads?path=");
for (LatLng trackPoint : trackPoints) {
url.append(String.format("%8.5f", trackPoint.latitude));
url.append(",");
url.append(String.format("%8.5f", trackPoint.longitude));
url.append("|");
}
url.delete(url.length() - 1, url.length());
url.append("&interpolate=true");
url.append(String.format("&key=%s", <your_Google_Maps_API_key>);
return url.toString();
}
private class GetSnappedPointsAsyncTask extends AsyncTask<List<LatLng>, Void, List<LatLng>> {
protected void onPreExecute() {
super.onPreExecute();
}
protected List<LatLng> doInBackground(List<LatLng>... params) {
List<LatLng> snappedPoints = new ArrayList<>();
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL(buildRequestUrl(params[0]));
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
InputStream stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuilder jsonStringBuilder = new StringBuilder();
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null) {
buffer.append(line+"\n");
jsonStringBuilder.append(line);
jsonStringBuilder.append("\n");
}
JSONObject jsonObject = new JSONObject(jsonStringBuilder.toString());
JSONArray snappedPointsArr = jsonObject.getJSONArray("snappedPoints");
for (int i = 0; i < snappedPointsArr.length(); i++) {
JSONObject snappedPointLocation = ((JSONObject) (snappedPointsArr.get(i))).getJSONObject("location");
double lattitude = snappedPointLocation.getDouble("latitude");
double longitude = snappedPointLocation.getDouble("longitude");
snappedPoints.add(new LatLng(lattitude, longitude));
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return snappedPoints;
}
@Override
protected void onPostExecute(List<LatLng> result) {
super.onPostExecute(result);
PolylineOptions polyLineOptions = new PolylineOptions();
polyLineOptions.addAll(result);
polyLineOptions.width(5);
polyLineOptions.color(Color.RED);
mGoogleMap.addPolyline(polyLineOptions);
LatLngBounds.Builder builder = new LatLngBounds.Builder();
builder.include(result.get(0));
builder.include(result.get(result.size()-1));
LatLngBounds bounds = builder.build();
mGoogleMap.animateCamera(CameraUpdateFactory.newLatLngBounds(bounds, 10));
}
}
}
并且不要忘记在Google APIs Console为您的项目添加Google Maps Roads API支持(选择您的项目,而不是选择Dashboard,而不是按“ENABLE APIS AND SERVICES”按钮,而不是在左侧“Filter by”选择“Maps”,而不是按“Google Maps Roads API”,最后按“ENABLE”按钮).
你应该得到这样的东西：
其中：蓝色折线 – 用于源点,红色折线 – 用于捕捉点.
请记住,每个用户(IP)每天限制100个GPS点数和2500个请求,每秒10个请求.此外,您还需要更优雅的解决方案,用于快速点JSON下载.
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