我开发的应用程序在运行时使用 GPSTracker.java 类按纬度和经度取城市名称，并将该城市名称添加到 url 以检索 json 数据。我的代码从 API 18 到 API 22 运行良好，但是现在当我在 API 23 上运行我的代码时，地理编码器不起作用并且城市名称为空 这是我在 Main Activity 上用于检索城市名称的代码：
// To get City-Name from coordinates
GPSTracker gpsTracker = new GPSTracker(getActivity());
String cityName = null;
Geocoder gcd = new Geocoder(getContext(), Locale.ENGLISH);
List<Address> addresses = null;
try {
addresses = gcd.getFromLocation(gpsTracker.getLatitude(), gpsTracker.getLongitude(), 1);
if (addresses.size() > 0) {
System.out.println(addresses.get(0).getLocality());
cityName = addresses.get(0).getLocality();
Log.d("nome_cit", "debug_cit " + cityName);
// Controllo formattazione nomi Car2Go
if(cityName.equals("Rome")) {
nome_citta = "Roma";
}else if (cityName.equals("Florence")){
nome_citta = "Firenze";
}
else if (cityName.equals("Milan")){
nome_citta = "Milano";
}
else if (cityName.equals("Turin")){
nome_citta = "Torino";
}else if (cityName.equals("New York")){
nome_citta = "NewYorkCity";
}else if (cityName.equals("Los Angeles")){
nome_citta = "LosAngeles";
}
else if (cityName.equals("San Diego")){
nome_citta = "SanDiego";
}
else if (cityName.equals("Twin Cities")){
nome_citta = "TwinCities";
}
else if (cityName.equals("Vienna")) {
nome_citta = "wien";
}
else if (cityName.equals("Munich")) {
nome_citta = "München";
}
else if (cityName.equals("Osler")) {
nome_citta = "Rheinland";
}
// Controllo formattazione JCDecaux
else if (cityName.equals("Valencia")) {
nome_citta_test = "Valence";
}
else if (cityName.equals("Parigi")) {
nome_citta_test = "Paris";
}
else if (cityName.equals("Besançon")){
nome_citta_test = "Besancon";
}
else if (cityName.equals("Créteil")) {
nome_citta_test = "Creteil";
}
else {
nome_citta = cityName;
nome_citta_test = cityName;
}
}
else {
}
} catch (IOException e) {
e.printStackTrace();
}
在我的位置的地图上，我设置了此权限：
if (ActivityCompat.checkSelfPermission(getContext(),
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager
.PERMISSION_GRANTED && ActivityCompat
.checkSelfPermission(getContext(),
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager
.PERMISSION_GRANTED) {
/*Toast.makeText(getActivity(),
"Need location permission for map.setMyLocationEnabled(true);",
Toast.LENGTH_LONG).show();*/
MultiplePermissionsListener snackbarMultiplePermissionsListener =
SnackbarOnAnyDeniedMultiplePermissionsListener.Builder
.with((ViewGroup) getView(), "La app ha bisogno di ablitare i permessi di localizzaione per mostrare la mappa")
.withOpenSettingsButton("Settings")
.withCallback(new Snackbar.Callback() {
@Override
public void onShown(Snackbar snackbar) {
// Event handler for when the given Snackbar has been dismissed
}
@Override
public void onDismissed(Snackbar snackbar, int event) {
// Event handler for when the given Snackbar is visible
}
})
.build();
Dexter.checkPermissions(snackbarMultiplePermissionsListener, Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION,Manifest.permission.READ_PHONE_STATE, Manifest.permission.GET_ACCOUNTS);
return;
}
这是我的 GPSTracker.java 类：
public final class GPSTracker implements LocationListener {
private final Context mContext;
// flag for GPS status
public boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
/**
* Function to get the user's current location
*
* @return
*/
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(Context.LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
Log.v("isGPSEnabled", "=" + isGPSEnabled);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
Log.v("isNetworkEnabled", "=" + isNetworkEnabled);
if (isGPSEnabled == false && isNetworkEnabled == false) {
// no network provider is enabled
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
location=null;
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
location=null;
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
// DecimalFormat latitude = new DecimalFormat("00.00");
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener Calling this function will stop using GPS in your
* app
* */
public void stopUsingGPS() {
if (locationManager != null) {
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude() {
if (location != null) {
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude() {
if (location != null) {
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
*
* @return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog On pressing Settings button will
* lauch Settings Options
* */
public void showSettingsAlert() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle(R.string.title);
// Setting Dialog Message
alertDialog
.setMessage(R.string.subtitle);
// On pressing Settings button
alertDialog.setPositiveButton(R.string.impostazioni,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(
Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton(R.string.cancella,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
alertDialog.setCancelable(false);
// Showing Alert Message
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}
我还注意到，在 API 23 上使用地点选择器我收到此错误：尝试在此代码的空对象引用上调用接口方法“int java.util.List.size()”：
if (resultCode == getActivity().RESULT_OK) {
Place place = PlaceAutocomplete.getPlace(getActivity(), data);
String addresses = place.getAddress().toString();
if (addresses != null) {
puntoA.setText(addresses);
}if (addresses.isEmpty()){
addresses = "(" + place.getLatLng().latitude + "," + place.getLatLng().longitude + ")";
puntoA.setText("nessun indirizzo disponibile " + addresses);
}
//puntoA.setText(addresses);
// Recupero coordinate
Geocoder geocoder = new Geocoder(getActivity());
List<Address> address = null;
try {
address = geocoder.getFromLocationName(addresses, 1);
} catch (IOException e) {
e.printStackTrace();
}
if(address.size() > 0) {
Lat = address.get(0).getLatitude();
Lon = address.get(0).getLongitude();
}
else if (address.size() == 0) {
Lat = place.getLatLng().latitude;
Lon = place.getLatLng().longitude;
}
而且这个功能在其他 API 版本上也能很好地工作有什么帮助吗？