【发布时间】：2019-04-19 11:07:57
【问题描述】：
我有一个没有 SIM 卡和 GPS 设置为节省电池模式的 Android 平板电脑。 平板电脑通过以太网（带电缆）连接到互联网，并通过 WIFI 连接到 LAN。 我编写了一个查找当前位置（城市名称）的代码，它在我的手机中运行良好。 （我手机的 GPS 处于活动状态并通过 wifi（调制解调器）或移动网络连接到互联网）。
package com.xenon.location;
import android.app.Activity;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
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.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import static android.content.Context.LOCATION_SERVICE;
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
private final Activity mActivity;
boolean isGPSEnabled = false;
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
Location location;
double latitude;
double longitude;
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1;
protected LocationManager locationManager;
public GPSTracker(Activity activity) {
this.mContext = activity.getBaseContext();
this.mActivity = activity;
getLocation();
}
public Location getLocation() {
try {
//locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
}else{
this.canGetLocation = true;
if (isNetworkEnabled) {
if (ContextCompat.checkSelfPermission(
mActivity, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(mActivity
, new String[]{android.Manifest.permission.ACCESS_COARSE_LOCATION}
, 0);
}
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
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;
}
public void stopUsingGPS() {
if (locationManager != null) {
if (ContextCompat.checkSelfPermission(mActivity, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(mActivity, new String[]{android.Manifest.permission.ACCESS_COARSE_LOCATION},
0);
locationManager.removeUpdates(GPSTracker.this);
}
}
}
public double getLatitude() {
if (location != null) {
latitude = location.getLatitude();
}
return latitude;
}
public double getLongitude() {
if (location != null) {
longitude = location.getLongitude();
}
return longitude;
}
public String getCityName() {
String result = "";
if (location != null) {
double latitude, longitude;
List<Address> list;
Locale locale = new Locale("tr");
Geocoder geocoder = new Geocoder(mContext, locale);
try {
list = geocoder.getFromLocation(getLatitude(), getLongitude(), 2);
Address address = list.get(0);
/*
String gpsMsg = "CountryCode: " + address.getCountryCode() +
" ,AdminArea : " + address.getAdminArea() +
" ,CountryName : " + address.getCountryName() +
" ,SubLocality : " + address.getSubLocality();
*/
result = address.getAdminArea();
} catch (IOException e) {
e.printStackTrace();
}
catch (Exception e){
}
}
return result;
}
public boolean canGetLocation() {
return this.canGetLocation;
}
public void showSettingsAlert() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
alertDialog.setTitle("GPS is settings");
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
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);
}
});
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
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) {
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
在平板电脑上运行时：
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
isNetworkEnabled 和 canGetLocation 总是返回 false；
【问题讨论】：
标签： dictionary networking gps location wifi