我是Android的新手，我正在创建一个基于GPS的应用程序。所以我已经在我的应用程序上实现了谷歌地图和位置点标识符，但它只需要我第一次尝试地理位置，当我移动时它没有得到更新。请帮我解决这个问题。谢谢。
package com.android.locationtracker;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.location.Location;
import android.location.LocationListener;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.Toast;
import com.android.app.AppConst;
import com.android.app.AppController;
import com.android.common.GPSTracker;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.Request.Method;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.JsonObjectRequest;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;
public class NearByActivity extends Activity {
private static final String TAG = "error";
private GoogleMap googleMap;
private static String URL = AppConst.GEOMETRY;
private static String URL_UPDATE = AppConst.GEOMETRY_UPDATE;
private String jsonResponse;
private ProgressDialog pDialog;
GPSTracker gps;
double latitude;
double longtitude;
String id;
String type;
List<Marker> markerList = new ArrayList<Marker>();
Marker marker;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.nearby_activity);
try {
// Loading map
initilizeMap();
googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
googleMap.getUiSettings().setCompassEnabled(true);
googleMap.getUiSettings().setRotateGesturesEnabled(true);
} catch (Exception e) {
e.printStackTrace();
}
gps = new GPSTracker(this);
if (gps.canGetLocation()) {
latitude = gps.getLatitude();
longtitude = gps.getLongtitude();
} else {
gps.showSettingAllerts();
}
new LoadGeo().execute();
}
private void initilizeMap() {
try {
if (googleMap == null) {
googleMap = ((MapFragment) getFragmentManager()
.findFragmentById(R.id.map)).getMap();
// check if map is created successfully or not
if (googleMap == null) {
Toast.makeText(getApplicationContext(),
"Sorry! unable to create maps", Toast.LENGTH_SHORT)
.show();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onResume() {
super.onResume();
initilizeMap();
}
private void hidePDialog() {
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
private class LoadGeo extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(NearByActivity.this);
pDialog.setMessage("Loading...");
pDialog.show();
//
}
@Override
protected Void doInBackground(Void... arg0) {
SharedPreferences prefs = getSharedPreferences("conetext",
Context.MODE_PRIVATE);
id = prefs.getString("userid", null);
type = prefs.getString("persontype", null);
Map<String, String> params = new HashMap<String, String>();
params.put("userid", id);
params.put("usertype", type);
params.put("lat", String.valueOf(latitude));
params.put("lng", String.valueOf(longtitude));
JsonObjectRequest req = new JsonObjectRequest(URL_UPDATE,
new JSONObject(params),
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
Log.d("map", "msg");
VolleyLog.v("Response:%n %s",
response.toString(4));
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.e("Error: ", error.getMessage());
}
});
// add the request object to the queue to be executed
AppController.getInstance().addToRequestQueue(req);
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
Thread thread = new Thread() {
@Override
public void run() {
try {
while (true) {
sleep(1000);
JsonArrayRequest req = new JsonArrayRequest(URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(
JSONArray response) {
Log.d(TAG, response.toString());
hidePDialog();
try {
markerList.clear();
googleMap.clear();
for (int i = 0; i < response
.length(); i++) {
JSONObject geo = (JSONObject) response
.get(i);
String usertype = geo
.getString("UserType");
MarkerOptions markerblue = new MarkerOptions();
markerblue.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_CYAN));
markerblue.position(new LatLng(latitude, longtitude));
googleMap.addMarker(markerblue);
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(
latitude, longtitude), 17));
if (usertype
.equals("driver")) {
double lat = geo
.getDouble("Lat");
double lng = geo
.getDouble("Lng");
MarkerOptions markerop = new MarkerOptions();
markerop.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
markerop.position(
new LatLng(lat,
lng))
.draggable(true)
.visible(true);
marker= googleMap
.addMarker(markerop);
markerList.add(marker);
}
}
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(
getApplicationContext(),
"Error: "
+ e.getMessage(),
Toast.LENGTH_LONG)
.show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(
VolleyError error) {
VolleyLog.d(
TAG,
"Error: "
+ error.getMessage());
Toast.makeText(
getApplicationContext(),
error.getMessage(),
Toast.LENGTH_SHORT).show();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(req);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
thread.start();
}
}
}
答案 0 :(得分：1)
您需要注册LocationListener并实现方法
@Override
public void onLocationChanged(Location location) {
//smth like this
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongtitude()), 17));
}
详细信息在https://developer.android.com/training/location/receive-location-updates.html
答案 1 :(得分：0)
您需要在特定时间间隔内执行此代码
if (gps.canGetLocation()) {
latitude = gps.getLatitude();
longtitude = gps.getLongtitude();
} else {
gps.showSettingAllerts();
}
new LoadGeo().execute();
我建议使用Handler.postDelayed（Runnable，Interval）方法来解决这个问题。
答案 2 :(得分：0)
您可以使用位置服务。这是代码：
通过提供所需频率（以分钟为单位）来调用此功能：
private void requestLocation(Context context, int frequency) //frequency in mins
{
LocationMgr loc_mgr = new LocationMgr(context);
loc_mgr.requestLocationUpdates(frequency);
}
以下是 LocationMgr 类：
public class LocationMgr implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener
{
private final Context context;
private GoogleApiClient googleApiClient;
private boolean inProgress;
public enum REQUEST_TYPE {START, STOP, LAST_KNOWN}
private REQUEST_TYPE requestType;
private Intent intent;
LocationRequest mLocationRequest;
LocationListener ll;
public LocationMgr(Context context)
{
this.context = context;
this.googleApiClient = new GoogleApiClient.Builder(context)
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
intent = new Intent(context, LocationService.class);
inProgress = false;
}
@Override
public void onConnectionFailed(ConnectionResult arg0) {
inProgress = false;
}
@Override
public void onConnectionSuspended(int arg0) {
googleApiClient.connect();
}
@Override
public void onConnected(Bundle connectionHint) {
PendingIntent pendingIntent = PendingIntent.getService(context, 123, intent, PendingIntent.FLAG_UPDATE_CURRENT);
switch (requestType)
{
case START :
LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, mLocationRequest, pendingIntent);
break;
case STOP :
LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient, pendingIntent);
break;
case LAST_KNOWN :
Location location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
ll.onNewLocationUpdate(location);
break;
default :
log.e("Unknown request type in onConnected().");
break;
}
inProgress = false;
googleApiClient.disconnect();
}
/**
*
* @param frequency (minutes) minimum time interval between location updates
*/
public void requestLocationUpdates(int frequency)
{
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(frequency * 60 * 1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest.setFastestInterval(1000);
if (inProgress)
{
log.e("A request is already underway");
return;
}
inProgress = true;
requestType = REQUEST_TYPE.START;
googleApiClient.connect();
}
public void removeContinuousUpdates()
{
if (inProgress)
{
log.e("A request is already underway");
return;
}
inProgress = true;
requestType = REQUEST_TYPE.STOP;
googleApiClient.connect();
}
public void getLastKnownLocation(LocationListener ll)
{
this.ll = ll;
if (inProgress)
{
log.e("A request is already underway");
return;
}
inProgress = true;
requestType = REQUEST_TYPE.LAST_KNOWN;
googleApiClient.connect();
}
}
以下是 LocationService 类：
public class LocationService extends IntentService
{
public LocationService()
{
super("NOTIFICATION_SERVICE");
}
/**
* Called when a new location update is available.
*/
@Override
protected void onHandleIntent(Intent intent)
{
LocationListener ll = new LocationListener()
{
@Override
public void onNewLocationUpdate(Location location)
{
// here you will get the latest location
}
};
LocationMgr lm = new LocationMgr(getApplicationContext());
lm.getLastKnownLocation(ll);
}
}