如何在android中显示从当前位置到固定目的地的路线
我想显示从当前位置到特定固定位置的路线。 我正在使用谷歌API。 以下是我的主要活动如何在android中显示从当前位置到固定目的地的路线,android,google-maps,Android,Google Maps,我想显示从当前位置到特定固定位置的路线。 我正在使用谷歌API。 以下是我的主要活动 public class MainActivity extends FragmentActivity { GoogleMap map; LatLng latLng; ArrayList<LatLng> markerPoints; LatLng point1 = new LatLng(21.134200700000000000, 79.125217400000000000); @Override p
public class MainActivity extends FragmentActivity {
GoogleMap map;
LatLng latLng;
ArrayList<LatLng> markerPoints;
LatLng point1 = new LatLng(21.134200700000000000, 79.125217400000000000);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
// Initializing
markerPoints = new ArrayList<LatLng>();
// Getting reference to SupportMapFragment of the activity_main
SupportMapFragment supportMapFragment =
(SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
map = supportMapFragment.getMap();
map.setMyLocationEnabled(true);
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = locationManager.getBestProvider(criteria, true);
Location location = locationManager.getLastKnownLocation(bestProvider);
if (location != null) {
onLocationChanged(location);
}
//locationManager.requestLocationUpdates(bestProvider, 20000, 0, this);
// Getting Map for the SupportMapFragment
map = supportMapFragment.getMap();
if(map!=null){
// Enable MyLocation Button in the Map
map.setMyLocationEnabled(true);
// Already two locations
if(markerPoints.size()>1){
markerPoints.clear();
map.clear();
}
// Adding new item to the ArrayList
markerPoints.add(point1);
// Creating MarkerOptions
MarkerOptions options = new MarkerOptions();
// Setting the position of the marker
options.position(point1);
/**
* 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));
}
// Add new marker to the Google Map Android API V2
map.addMarker(options);
// 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 = 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 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 = 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();
// 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);
double lat = Double.parseDouble(point.get(21.134200700000000000));
double lng = Double.parseDouble(point.get( 79.125217400000000000));
LatLng position = new LatLng(lat, lng);
points.add(position);
points.add(latLng);
}
// Adding all the points in the route to LineOptions
lineOptions.addAll(points);
lineOptions.width(2);
lineOptions.color(Color.RED);
}
// Drawing polyline in the Google Map for the i-th route
map.addPolyline(lineOptions);
}
}
public void onLocationChanged(Location location) {
double latitude = location.getLatitude();
double longitude = location.getLongitude();
latLng = new LatLng(latitude, longitude);
map.addMarker(new MarkerOptions().position(latLng));
map.moveCamera(CameraUpdateFactory.newLatLng(latLng));
map.animateCamera(CameraUpdateFactory.zoomTo(15));
}
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
private boolean isGooglePlayServicesAvailable() {
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if (ConnectionResult.SUCCESS == status) {
return true;
} else {
GooglePlayServicesUtil.getErrorDialog(status, this, 0).show();
return false;
}
}
}
public类MainActivity扩展了FragmentActivity{
谷歌地图;
LatLng LatLng;
ArrayList markerPoints;
LatLng point1=新LatLng(21.1342007000000000,79.125217400000000);
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main_活动);
//初始化
markerPoints=newarraylist();
//获取对活动\u main的SupportMapFragment的引用
SupportMapFragment SupportMapFragment=
(SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map);
map=supportMapFragment.getMap();
map.setMyLocationEnabled(true);
LocationManager LocationManager=(LocationManager)getSystemService(LOCATION\u服务);
标准=新标准();
字符串bestProvider=locationManager.getBestProvider(条件为true);
Location Location=locationManager.getLastKnownLocation(bestProvider);
如果(位置!=null){
onLocationChanged(位置);
}
//locationManager.RequestLocationUpdate(bestProvider,20000,0,this);
//正在获取SupportMapFragment的映射
map=supportMapFragment.getMap();
if(map!=null){
//在地图中启用MyLocation按钮
map.setMyLocationEnabled(true);
//已经有两个地点了
if(markerPoints.size()>1){
markerPoints.clear();
map.clear();
}
//向ArrayList添加新项
添加标记点(点1);
//创建标记选项
MarkerOptions options=新的MarkerOptions();
//设置标记的位置
选项。位置(第1点);
/**
*对于起始位置,标记的颜色为绿色和白色
*对于结束位置,标记的颜色为红色。
*/
if(markerPoints.size()==1){
图标(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
}else if(markerPoints.size()==2){
图标(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
}
//向Google Map Android API V2添加新标记
map.addMarker(选项);
//检查是否捕获开始和结束位置
如果(markerPoints.size()>=2){
LatLng origin=markerPoints.get(0);
LatLng dest=标记点获取(1);
//获取Google Directions API的URL
字符串url=getDirectionsUrl(源、目标);
DownloadTask DownloadTask=新的DownloadTask();
//开始从Google Directions API下载json数据
downloadTask.execute(url);
}
}
}
私有字符串getDirectionsUrl(LatLng来源,LatLng目的地){
//路线起点
字符串str_origin=“origin=“+origin.latitude+”,“+origin.longitude;
//路线目的地
字符串str_dest=“destination=”+dest.latitude+”,“+dest.longitude;
//传感器启用
字符串sensor=“sensor=false”;
//为web服务构建参数
字符串参数=str_origin+“&”+str_dest+“&”+传感器;
//输出格式
字符串输出=“json”;
//构建web服务的url
字符串url=”https://maps.googleapis.com/maps/api/directions/“+输出+”?“+参数;
返回url;
}
/**从url下载json数据的方法*/
私有字符串下载URL(字符串strUrl)引发IOException{
字符串数据=”;
InputStream iStream=null;
HttpURLConnection-urlConnection=null;
试一试{
URL=新URL(strUrl);
//创建http连接以与url通信
urlConnection=(HttpURLConnection)url.openConnection();
//连接到url
urlConnection.connect();
//从url读取数据
iStream=urlConnection.getInputStream();
BufferedReader br=新的BufferedReader(新的InputStreamReader(iStream));
StringBuffer sb=新的StringBuffer();
字符串行=”;
而((line=br.readLine())!=null){
某人附加(行);
}
data=sb.toString();
br.close();
}捕获(例外e){
Log.d(“下载url时出现异常”,例如toString());
}最后{
iStream.close();
urlConnection.disconnect();
}
返回数据;
}
//从传递的url获取数据
私有类DownloadTask扩展了AsyncTask{
//在非ui线程中下载数据
@凌驾
受保护的字符串doInBackground(字符串…url){
//用于存储来自web服务的数据
字符串数据=”;
试一试{
//从web服务获取数据
数据=下载url(url[0]);
}捕获(例外e){
Log.d(“后台任务”,例如toString());
}
返回数据;
}
//在UI线程中执行,在
//doInBackground()
@凌驾
受保护的void onPostExecute(字符串结果){
super.onPostExecute(结果);
ParserTask ParserTask=新的ParserTask();
//调用线程以解析JSON数据
执行(结果);
}
}
/**以JSON格式解析GooglePlaces的类*/
私有类ParserTask扩展了AsyncTask{
//解析非ui线程中的数据
@凌驾
受保护列表doInBackground(字符串…jsonData){
JSONObject jObject;
列表路由=空;
试一试{
jObject=新的JSONObject(jsonData[0]);
DirectionsJSONParser=新的DirectionsJSONParser();
//开始解析数据
routes=parser.parse(jObject);
}捕获(例外e){
e、 printStackTrace();
}
返回路线;
}
//解析过程后,在UI线程中执行
@凌驾
try {
//Tranform the string into a json object
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 = decodePoly(encodedString);
} 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;
}
for (int z = 0; z < list.size() - 1; z++) {
LatLng src = list.get(z);
LatLng dest = list.get(z + 1);
//
lines.add(map.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude), new LatLng(dest.latitude, dest.longitude))
.width(2)
.color(Color.RED).geodesic(true)));
}