我正在尝试计算用户位置到两个目的地之间的最短路径 并将距离值放入数组中。
而是将所有计算放入数组中，我在数组中得到的结果只是距离第二个目标的距离。显然我的程序擦除了第一次计算，然后开始下一次计算。我应该纠正什么，以便我的程序不会擦除第一次计算并将所有距离放入数组？
它应该是这样的：
distance1 =从用户locationA到LocationH的距离
distance2 =距用户locationA到LocationI的距离
添加距离distanArray
结果是distanArray =（distance1，distance2）
我现在拥有的：
distanArray =（距离2）
这是我的代码
public class MainActivity extends FragmentActivity implements LocationListener {
TextView tvDistanceDuration;
TextView tvDistanceDuration2;
TextView tvDistanceDuration3;
private LocationManager locationManager;
private String provider;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_calcdistance);
tvDistanceDuration = (EditText) findViewById(R.id.editText1);
tvDistanceDuration2 = (EditText) findViewById(R.id.editText2);
tvDistanceDuration3 = (EditText) findViewById(R.id.editText3);
// Get the location manager
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
// Initialize the location fields
if (location != null) {
System.out.println("Provider " + provider + " has been selected.");
onLocationChanged(location);
}
else {
Toast.makeText( getApplicationContext(),
"Location not available",
Toast.LENGTH_LONG).show();
}
}
/* Request updates at startup */
@Override
protected void onResume() {
super.onResume();
locationManager.requestLocationUpdates(provider, 400, 1, this);
}
/* Remove the location listener updates when Activity is paused */
@Override
protected void onPause() {
super.onPause();
locationManager.removeUpdates(this);
}
@Override
public void onLocationChanged(Location location) {
double lat = (double) (location.getLatitude());
double lon = (double) (location.getLongitude());
Location locationA = new Location("USER");
locationA.setLatitude(lat);
locationA.setLongitude(lon);
List<LatLng> pointss = new ArrayList<LatLng>();
List<LatLng> pointsss = new ArrayList<LatLng>();
Location locationH = new Location("Shelter 7");
locationH.setLatitude(-0.868101);
locationH.setLongitude(119.888341);
Location locationI = new Location("Shelter 8");
locationI.setLatitude(-0.900198);
locationI.setLongitude(119.88856);
LatLng des = new LatLng(locationA.getLatitude(), locationA.getLongitude());
LatLng des1 = new LatLng(locationH.getLatitude(), locationH.getLongitude());
LatLng des2 = new LatLng(locationI.getLatitude(), locationI.getLongitude());
pointss.add(des1);
pointss.add(des2);
pointsss.add(des);
tvDistanceDuration3.setText(String.valueOf(pointss));
for (int i = 0; i <(pointss.size()); i++) {
LatLng origin = pointsss.get(0);
LatLng dest = pointss.get(i);
// 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;
String distance = "";
String duration = "";
ArrayList<String> distan = new ArrayList<String>();
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();
points = new ArrayList<LatLng>();
// 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");
distan.add(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(2);
lineOptions.color(Color.RED);
}
String minDist = Collections.min(distan);
tvDistanceDuration.setText("Distance:"+minDist + ", Duration:"+duration);
tvDistanceDuration2.setText(String.valueOf(distan));
}
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}