java - 无法在谷歌地图中绘制路线
问题描述
我试图画一条从起点到终点的路线，但我得到的只是这些地点的一个标记，没有任何路线连接
这是我所拥有的图片
请问如何连接我的位置以下是我的代码：
地图活动：
class MapsActivity : AppCompatActivity(), OnMapReadyCallback {
private lateinit var mMap: GoogleMap
private val LOWER_MANHATTAN = LatLng(
40.722543,
-73.998585
)
private val BROOKLYN_BRIDGE = LatLng(40.7057, -73.9964)
private val WALL_STREET = LatLng(40.7064, -74.0094)
val TAG = "PathGoogleMapActivity"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_maps)
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
val mapFragment = supportFragmentManager
.findFragmentById(R.id.map) as SupportMapFragment
mapFragment.getMapAsync(this)
}
private fun addMarkers() {
if (mMap != null){
mMap.addMarker(MarkerOptions().position(BROOKLYN_BRIDGE)
.title("First point"))
mMap.addMarker(MarkerOptions().position(LOWER_MANHATTAN)
.title("Second point"))
mMap.addMarker(MarkerOptions().position(WALL_STREET)
.title("Third point"))
}
}
/* fun getMapsApiDirectionsUrl(): String{
val waypoints = ("waypoints=optimize:true|"
+ LOWER_MANHATTAN.latitude + "," + LOWER_MANHATTAN.longitude
+ "|" + "|" + BROOKLYN_BRIDGE.latitude + ","
+ BROOKLYN_BRIDGE.longitude + "|" + WALL_STREET.latitude + ","
+ WALL_STREET.longitude)
val sensor = "sensor=false"
val params = "$waypoints&$sensor"
val output = "json"
return ("https://maps.googleapis.com/maps/api/directions/"
+ output + "?" + params)
}*/
private fun getMapsApiDirectionsUrl(): String {
val waypoints = ("waypoints=optimize:true|"
+ LOWER_MANHATTAN.latitude + "," + LOWER_MANHATTAN.longitude
+ "|" + "|" + WALL_STREET.latitude + ","
+ WALL_STREET.longitude)
val OriDest =
"origin=" + LOWER_MANHATTAN.latitude + "," + LOWER_MANHATTAN.longitude + "&destination=" + WALL_STREET.latitude + "," + WALL_STREET.longitude
val sensor = "sensor=false"
val params = "$OriDest&%20$waypoints&$sensor"
val output = "json"
return ("https://maps.googleapis.com/maps/api/directions/"
+ output + "?" + params)
}
override fun onMapReady(googleMap: GoogleMap) {
mMap = googleMap
// Add a marker in Sydney and move the camera
val sydney = LatLng(-34.0, 151.0)
mMap.addMarker(MarkerOptions().position(sydney).title("Marker in Sydney"))
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney))
val options = MarkerOptions()
options.position(LOWER_MANHATTAN)
options.position(BROOKLYN_BRIDGE)
options.position(WALL_STREET)
mMap.addMarker(options)
val url = getMapsApiDirectionsUrl()
val downloadTask = ReadTask(this)
downloadTask.execute(url)
mMap.moveCamera(
CameraUpdateFactory.newLatLngZoom(
BROOKLYN_BRIDGE,
13f
)
)
addMarkers()
}
private class ReadTask(mapsActivity: MapsActivity) : AsyncTask<String,Void,String>(){
private val activityReference: WeakReference<MapsActivity> = WeakReference(mapsActivity)
override fun doInBackground(vararg p0: String?): String {
var data = ""
try {
val http = HttpConnection()
data = http.readUrl(p0[0])
} catch (e: Exception) {
Log.d("Background Task", e.toString())
}
return data
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
val activity = activityReference.get()
if (activity == null || activity.isFinishing) return
ParserTask(activity).execute(result)
}
}
private class ParserTask(context: MapsActivity) : AsyncTask<String,Int, List<List<HashMap<String,String>>>>() {
private val activityReference: WeakReference<MapsActivity> = WeakReference(context)
override fun doInBackground(vararg p0: String?): List<List<HashMap<String, String>>> {
val jObject: JSONObject
var routes: List<List<HashMap<String, String>>>? = null
try {
jObject = JSONObject(p0[0])
val parser = PathJSONParser()
routes = parser.parse(jObject)
} catch (e: Exception) {
e.printStackTrace()
}
return routes!!
}
override fun onPostExecute(routes: List<List<HashMap<String, String>>>?) {
super.onPostExecute(routes)
val activity = activityReference.get()
if (activity == null || activity.isFinishing) return
try {
var points: ArrayList<LatLng>
var polyLineOptions: PolylineOptions? = null
// traversing through routes
for (i in 0 until routes!!.size) {
points = ArrayList()
polyLineOptions = PolylineOptions()
val path = routes[i]
for (j in path.indices) {
val point = path[j]
val lat = java.lang.Double.parseDouble(point["lat"]!!)
val lng = java.lang.Double.parseDouble(point["lng"]!!)
val position = LatLng(lat, lng)
points.add(position)
}
polyLineOptions.addAll(points)
polyLineOptions.width(2f)
polyLineOptions.color(Color.BLUE)
}
activity.mMap.addPolyline(polyLineOptions)
} catch (e: Exception) {
}
}
}
}
PathJSONParser 类：
public class PathJSONParser {
public 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");
/* Traversing all routes */
for (int i = 0; i < jRoutes.length(); i++) {
jLegs = ((JSONObject) jRoutes.get(i)).getJSONArray("legs");
List<HashMap<String, String>> path = new ArrayList<>();
/* Traversing all legs */
for (int j = 0; j < jLegs.length(); j++) {
jSteps = ((JSONObject) jLegs.get(j)).getJSONArray("steps");
/* Traversing all 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);
/* Traversing all points */
for (int l = 0; l < list.size(); l++) {
HashMap<String, String> hm = new HashMap<String, String>();
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;
}
/**
* Method Courtesy :
* jeffreysambells.com/2010/05/27
* /decoding-polylines-from-google-maps-direction-api-with-java
* */
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;
}
}
请我需要帮助来解决这个问题，我整天都在做这个。谢谢
解决方案
我终于得到了我需要的解决方案：首先要知道从 Google 获得的 API KEY 是绘制路线的关键。所以 ：
private fun getMapsApiDirectionsUrl(): String {
val waypoints = ("waypoints=optimize:true|"
+ LOWER_MANHATTAN.latitude + "," + LOWER_MANHATTAN.longitude
+ "|" + "|" + WALL_STREET.latitude + "," + WALL_STREET.longitude
+"|" + "|" + BROOKLYN_BRIDGE.latitude + "," + BROOKLYN_BRIDGE.longitude)
val OriDest =
"origin=" + LOWER_MANHATTAN.latitude + "," + LOWER_MANHATTAN.longitude + "&destination=" + WALL_STREET.latitude + "," + WALL_STREET.longitude
val sensor = "sensor=false"
val params = "$OriDest&%20$waypoints&$sensor"
val output = "json"
return ("https://maps.googleapis.com/maps/api/directions/"
+ output + "?" + params)
}
上面的方法为我提供了包含我的起点和终点的 URL，以及谷歌处理信息并返回我需要的 JSON 值所需的其他参数。所以在我将它传递给我的 Asyntask 调用时，我像这样附加我的 Google API KEY：
val url = getMapsApiDirectionsUrl()+"&key=API_KEY"
val downloadTask = ReadTask(this)
downloadTask.execute(url)
就是这样！因此，请确保将您的 Google API_KEY 附加到您的 URL，然后再将其传递给您的 Asyntask 类。希望这对某人有所帮助：我非常欣喜若狂，我终于想通了 :) :)
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