我需要获取当前设备位置（lat / lng）但是＆＃34; getCurrentLocation（）＆＃34;节目＆＃34;没有提供者＆＃34;所有时间所以位置为空。我在onCreate（）中调用此方法，并在Manifest文件中声明所有权限：
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
也启用了实际设备上的位置服务。
getCurrentLocation（）java代码：
public void getCurrentLocation() {
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
Criteria c = new Criteria();
provider = locationManager.getBestProvider(c, false);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
location = locationManager.getLastKnownLocation(provider);
if(location!=null)
{
double lng=location.getLongitude();
double lat=location.getLatitude();
Toast.makeText(this, Double.toString(lat) + "\n" + Double.toString(lng), Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(this, "No provider", Toast.LENGTH_SHORT).show();
}
}
我该如何解决？
P.S。：我修改了很多类似的问题，但无法找到合适的解决方案。
答案 0 :(得分：0)
首先考虑使用FusedLocationProvider而不是LocationManager。 Here您可以找到如何使用ID的指南。
第二 - 你正试图获得＆＃34;最后知道的位置＆＃34;而且它永远不会在那里。要接收用户位置，您需要订阅LocationManager更新。 This是如何做到的示例。
答案 1 :(得分：0)
provider = locationManager.getBestProvider(c, true);
在代码中尝试此更改
答案 2 :(得分：0)
无法保证.getLastKnownLocation()返回先前存储的位置数据。
它可以返回null。
因此，您必须为需要侦听位置更新的情况做好准备。你这样注册给他们：
locationManager
.requestLocationUpdates(provider, 0, 0,
new LocationListener() {
@Override
public void onLocationChanged(Location location) {
//here you receive the new location
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
}););
答案 3 :(得分：-2)
public class GPSTracker extends Service implements LocationListener {
private final Activity mContext;
// flag for GPS status
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
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Activity context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// First get location from Network Provider
checkLocationPermission();
if (isNetworkEnabled) {
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) {
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();
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){
checkLocationPermission();
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("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("Please enable GPS to get locations.");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", 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("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// 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) {
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
public boolean checkLocationPermission()
{
if (ContextCompat.checkSelfPermission(mContext, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)
{
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(mContext, android.Manifest.permission.ACCESS_FINE_LOCATION))
{
// Show an expanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
//Prompt the user once explanation has been shown
ActivityCompat.requestPermissions(mContext, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
else
{
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(mContext, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
}
else
{
if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER))
{
showGPSDisabledAlertToUser();
}
return true;
}
}
private void showGPSDisabledAlertToUser()
{
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(mContext);
alertDialogBuilder.setMessage("GPS is disabled in your device. Would you like to enable it?")
.setCancelable(false)
.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Intent callGPSSettingIntent = new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(callGPSSettingIntent);
}
});
alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
dialog.cancel();
}
});
AlertDialog alert = alertDialogBuilder.create();
alert.show();
}
}
尝试此代码，无论何时需要获取位置，都会创建一个GPS对象并检索lat和long
例如：
GPSTracker gpsTracker = new GPSTracker(activity);
Latitude = gpsTracker.getLatitude();
Longtude = gpsTracker.getLongitude();