如何在 Android 中获取位置管理器的最后一个已知位置？
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【中文标题】如何在 Android 中获取位置管理器的最后一个已知位置？【英文标题】：How to get last known location for Location manager in Android? 【发布时间】：2014-10-18 10:51:43 【问题描述】：我正在使用简单的 位置管理器 对象来获取设备的 lastKnownLocation() 但是在 return 中获取 null object 谁能告诉我为什么？
代码：
public Location getLocation()
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
if (locationManager != null)
Location lastKnownLocationGPS = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (lastKnownLocationGPS != null)
return lastKnownLocationGPS;
else
Location loc = locationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
System.out.println("1::"+loc);----getting null over here
System.out.println("2::"+loc.getLatitude());
return loc;
else
return null;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.location);
getLocation();-----calling service
已授予权限：
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
所以有什么需要设置的吗？我已检查我的位置服务是否已在设备中开启 请提供一些工作示例的链接
【问题讨论】：
关注最新文档请developer.android.com/training/location/… :) 也检查一下***.com/a/15997304/3020568 @deniz thnks 我正在实现你给出的第一个链接。我得到 lastLocation 的空值这里是代码 if (mUpdatesRequested) mLocationClient.requestLocationUpdates(mLocationRequest, this); 不使用启用的“使用无线网络”和“位置和 Google 搜索” 您在开发者文档中尝试过该示例吗？希望对你有帮助 【参考方案1】：在获取最后一个位置之前，也许你想获取当前位置，检查是否为 null 或有。如果您想使用FusedLocationProviderClient ，则未设置最后一个位置 在使用它之前添加这个：
实现 'com.google.android.gms:play-services-location:16.0.0'
在您的 build.gradle(Module: app) 上，并在活动创建时调用方法 zoomMyCuurentLocation()。
private void zoomMyCuurentLocation()
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)
ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION);
Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
if (location != null)
double lat = location.getLatitude();
double longi = location.getLongitude();
LatLng latLng = new LatLng(lat,longi);
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 14.f));
Log.d(TAG, "zoomMyCuurentLocation: location not null");
else
setMyLastLocation();
private void setMyLastLocation()
Log.d(TAG, "setMyLastLocation: excecute, and get last location");
FusedLocationProviderClient fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
return;
fusedLocationClient.getLastLocation().addOnSuccessListener(this, new OnSuccessListener<Location>()
@Override
public void onSuccess(Location location)
if (location != null)
double lat = location.getLatitude();
double longi = location.getLongitude();
LatLng latLng = new LatLng(lat,longi);
Log.d(TAG, "MyLastLocation coordinat :"+latLng);
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 14.f));
);
【讨论】：
【参考方案2】：对此的回答很愚蠢……我重新启动了我的设备……它工作了……请确保您的位置服务已启用并正常工作
【讨论】：
【参考方案3】：我用来获取地点名称的位置是
GPSTracker gpsTracker = new GPSTracker(CameraActivity.this);
String stringLatitude = "", stringLongitude = "", nameOfLocation="";
if (gpsTracker.canGetLocation())
stringLatitude = String.valueOf(gpsTracker.latitude);
stringLongitude = String.valueOf(gpsTracker.longitude);
nameOfLocation = ConvertPointToLocation(stringLatitude,stringLongitude);
public String ConvertPointToLocation(String Latitude, String Longitude)
String address = "";
Geocoder geoCoder = new Geocoder(getBaseContext(), Locale.getDefault());
try
List<Address> addresses = geoCoder.getFromLocation(
Float.parseFloat(Latitude), Float.parseFloat(Longitude), 1);
if (addresses.size() > 0)
for (int index = 0; index < addresses.get(0)
.getMaxAddressLineIndex(); index++)
address += addresses.get(0).getAddressLine(index) + " ";
catch (IOException e)
e.printStackTrace();
return address;
GPSTracker.java
package in.appology.lss;
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
/**
* Create this Class from tutorial :
* http://www.androidhive.info/2012/07/android-gps-location-manager-tutorial
*
* For Geocoder read this :
* http://***.com/questions/472313/android-reverse
* -geocoding-getfromlocation
*
*/
public class GPSTracker extends Service implements LocationListener
private final Context mContext;
// flag for GPS Status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
Location location;
double latitude;
double longitude;
// The minimum distance to change updates in metters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10
// metters
// The minimum time beetwen 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(Context 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
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);
updateGPSCoordinates();
// 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);
updateGPSCoordinates();
catch (Exception e)
// e.printStackTrace();
Log.e("Error : Location",
"Impossible to connect to LocationManager", e);
return location;
public void updateGPSCoordinates()
if (location != null)
latitude = location.getLatitude();
longitude = location.getLongitude();
/**
* 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;
/**
* Function to get longitude
*/
public double getLongitude()
if (location != null)
longitude = location.getLongitude();
return longitude;
/**
* Function to check GPS/wifi enabled
*/
public boolean canGetLocation()
return this.canGetLocation;
/**
* Function to show settings alert dialog
*/
public void showSettingsAlert()
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS");
// Setting Dialog Message
alertDialog
.setMessage("Please enable location in settings for accurate results!");
// On Pressing Setting button
alertDialog.setPositiveButton("Settings",
new DialogInterface.OnClickListener()
@Override
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()
@Override
public void onClick(DialogInterface dialog, int which)
dialog.cancel();
);
alertDialog.show();
/**
* Get list of address by latitude and longitude
*
* @return null or List<Address>
*/
public List<Address> getGeocoderAddress(Context context)
if (location != null)
Geocoder geocoder = new Geocoder(context, Locale.ENGLISH);
try
List<Address> addresses = geocoder.getFromLocation(latitude,
longitude, 1);
return addresses;
catch (IOException e)
// e.printStackTrace();
Log.e("Error : Geocoder", "Impossible to connect to Geocoder",
e);
return null;
/**
* Try to get AddressLine
*
* @return null or addressLine
*/
public String getAddressLine(Context context)
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
Address address = addresses.get(0);
String addressLine = address.getAddressLine(0);
return addressLine;
else
return null;
/**
* Try to get Locality
*
* @return null or locality
*/
public String getLocality(Context context)
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
Address address = addresses.get(0);
String locality = address.getLocality();
return locality;
else
return null;
/**
* Try to get Postal Code
*
* @return null or postalCode
*/
public String getPostalCode(Context context)
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
Address address = addresses.get(0);
String postalCode = address.getPostalCode();
return postalCode;
else
return null;
/**
* Try to get CountryName
*
* @return null or postalCode
*/
public String getCountryName(Context context)
List<Address> addresses = getGeocoderAddress(context);
if (addresses != null && addresses.size() > 0)
Address address = addresses.get(0);
String countryName = address.getCountryName();
return countryName;
else
return null;
@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 intent)
return null;
【讨论】：
我正在使用 googlePlayLocation 服务而不是 GPS 它正在运行获取位置的服务。问这个问题的人从来没有提到在特定的时间间隔进行位置报告。不适合提出的问题【参考方案4】：我发现的最佳方法：
private Location getLastKnownLocation()
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED || ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
return null;
List<String> providers = locationManager.getProviders(true);
Location bestLocation = null;
for (String provider : providers)
Location l = locationManager.getLastKnownLocation(provider);
if (l == null)
continue;
if (bestLocation == null || l.getAccuracy() < bestLocation.getAccuracy())
// Found best last known location:
bestLocation = l;
return bestLocation;
locationManager变量可以从系统服务LOCATION获取。
【讨论】：
缺失：LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);上面列出 // Get the location from the given provider
Location location = locationManager
.getLastKnownLocation(provider);
locationManager.requestLocationUpdates(provider, 1000, 1, this);
【讨论】：
【参考方案6】：要获取最后一个位置，您可以参考上面提供的答案，您可以在其中使用 Location Manager 或 FusedLocationClient
但您也可以使用比其他方法更快的 LocationServices。
所以让我提供一个简短的工作：
1) 在你的 gradle 应用文件中添加这两个依赖项
implementation 'com.google.android.gms:play-services-maps:17.0.0'
implementation 'com.google.android.gms:play-services-location:17.0.0'
2) 在应用标签外的清单文件中添加这些权限
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
3) 在onCreate之外声明变量
private FusedLocationProviderClient fusedLocationClient;
4) 现在在 onCreate 中：
fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
fetchLastLocation();
5) 没有定义fetchLastLocation方法
private void fetchLastLocation()
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
// TODO: Consider calling
// Activity#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 Activity#requestPermissions for more details.
// Toast.makeText(MainActivity.this, "Permission not granted, Kindly allow permission", Toast.LENGTH_LONG).show();
showPermissionAlert();
return;
fusedLocationClient.getLastLocation()
.addOnSuccessListener(this, new OnSuccessListener<Location>()
@Override
public void onSuccess(Location location)
// Got last known location. In some rare situations this can be null.
if (location != null)
// Logic to handle location object
Log.e("LAST LOCATION: ", location.toString());
);
6) 现在定义另外两种权限请求方法
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
switch (requestCode)
case 123:
// If request is cancelled, the result arrays are empty.
if (grantResults[0] == PackageManager.PERMISSION_DENIED)
// permission was denied, show alert to explain permission
showPermissionAlert();
else
//permission is granted now start a background service
if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
&& ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED)
fetchLastLocation();
private void showPermissionAlert()
if (ActivityCompat.checkSelfPermission(MainHomeActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
&& ActivityCompat.checkSelfPermission(MainHomeActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
ActivityCompat.requestPermissions(MainHomeActivity.this, new String[]Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION, 123);
注意：用你的类上下文替换上下文
您将在 Logcat 中获得您的位置。
希望这会希望你或其他人
【讨论】：
【参考方案7】：以下是我试图获取最后一个位置的方式。
private void setUpMap()
//Location location = mMap.getMyLocation();
mMap.setMyLocationEnabled(true);
//mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener()
@Override
public void onMyLocationChange(Location location)
mMap.addMarker(new MarkerOptions().position(new LatLng(location.getLatitude(), location.getLongitude())).title("My Location"));
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(),location.getLongitude()),10));
mMap.setOnMyLocationChangeListener(null);
);
【讨论】：
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