Java android纬度和经度返回0.0

我正在使用NET_PROVIDER检查当前的经度和纬度，并在应用程序中将它们打印为toast消息。 但是，在权限设置和连接网络的情况下，经度和纬度始终返回0.0

我为修复此问题所做的：

设置权限

在

onLocationChanged

方法中保存了以前的位置

我尝试了emulator和real device（api22）。但两者都返回0给我

这是我的密码

TrackGps.java：

import android.Manifest;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;

import android.content.pm.PackageManager;
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.v4.app.ActivityCompat;
import android.util.Log;
import android.widget.Toast;

/**
 * Created by Hannah Liao on 5/7/2017
 */

public class TrackGps extends Service implements LocationListener {

    private final Context mContext;

    boolean checkNetwork = false;

    boolean canGetLocation = false;
    LocationListener locationListener;
    Location loc ;
    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 TrackGps(Context mContext) {
        this.mContext = mContext;
        getLocation();
    }

    private Location getLocation() {

        try {
            locationManager = (LocationManager) mContext
                    .getSystemService(LOCATION_SERVICE);

            checkNetwork = locationManager
                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if(!checkNetwork) {
                Toast.makeText(mContext, "No Service Provider Available", Toast.LENGTH_SHORT).show();
            } else {
                this.canGetLocation = true;
                // First get location from Network Provider
                if (checkNetwork) {
                    Toast.makeText(mContext, "Network", Toast.LENGTH_SHORT).show();

                    try {
                        locationManager.requestLocationUpdates(
                                LocationManager.NETWORK_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        Log.d("Network", "Network");

                        if (locationManager != null) {
                            loc = locationManager
                                    .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                            this.onLocationChanged(loc);
                        }

                        if (loc != null) {
                            latitude = loc.getLatitude();
                            longitude = loc.getLongitude();
                        }
                    } catch (SecurityException e) {

                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            // otherwise just use network
           /*if (checkGPS) {
                Toast.makeText(mContext, "GPS", Toast.LENGTH_SHORT).show();
                if (loc == null) {
                    try {
                        locationManager.requestLocationUpdates(
                                LocationManager.GPS_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListener);
                        Log.d("GPS Enabled", "GPS Enabled");
                        if (locationManager != null) {
                            loc = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            if (loc != null) {
                                latitude = loc.getLatitude();
                                longitude = loc.getLongitude();
                            }
                        }
                    } catch (SecurityException e) {

                    }
                }
            }*/

        } catch (Exception e) {
            e.printStackTrace();
        }

        return loc;
    }

    public double getLongitude() {
        if (loc != null) {
            longitude = loc.getLongitude();
        }
        return longitude;
    }

    public double getLatitude() {
        if (loc != null) {
            latitude = loc.getLatitude();
        }
        return latitude;
    }

    public boolean canGetLocation() {
        return this.canGetLocation;
    }

    public void showSettingsAlert() {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);


        alertDialog.setTitle("GPS Not Enabled");

        alertDialog.setMessage("Do you wants to turn On GPS");


        alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);
            }
        });


        alertDialog.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });


        alertDialog.show();
    }



    public void stopUsingGPS() {
        if (locationManager != null) {

            locationManager.removeUpdates(TrackGps.this);
        }
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onLocationChanged(Location location) {
            this.loc = location;
            getLocation();
            getLongitude();
            getLatitude();
    }

    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.map.hannah.location3">

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-feature android:name="android.hardware.location.gps" />
    <application


        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <service android:name=".TrackGps" android:enabled="true" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.map.hannah.location3"
        minSdkVersion 17
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
}

MainActivity.java

清单：

import android.Manifest;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;

import android.content.pm.PackageManager;
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.v4.app.ActivityCompat;
import android.util.Log;
import android.widget.Toast;

/**
 * Created by Hannah Liao on 5/7/2017
 */

public class TrackGps extends Service implements LocationListener {

    private final Context mContext;

    boolean checkNetwork = false;

    boolean canGetLocation = false;
    LocationListener locationListener;
    Location loc ;
    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 TrackGps(Context mContext) {
        this.mContext = mContext;
        getLocation();
    }

    private Location getLocation() {

        try {
            locationManager = (LocationManager) mContext
                    .getSystemService(LOCATION_SERVICE);

            checkNetwork = locationManager
                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if(!checkNetwork) {
                Toast.makeText(mContext, "No Service Provider Available", Toast.LENGTH_SHORT).show();
            } else {
                this.canGetLocation = true;
                // First get location from Network Provider
                if (checkNetwork) {
                    Toast.makeText(mContext, "Network", Toast.LENGTH_SHORT).show();

                    try {
                        locationManager.requestLocationUpdates(
                                LocationManager.NETWORK_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        Log.d("Network", "Network");

                        if (locationManager != null) {
                            loc = locationManager
                                    .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                            this.onLocationChanged(loc);
                        }

                        if (loc != null) {
                            latitude = loc.getLatitude();
                            longitude = loc.getLongitude();
                        }
                    } catch (SecurityException e) {

                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            // otherwise just use network
           /*if (checkGPS) {
                Toast.makeText(mContext, "GPS", Toast.LENGTH_SHORT).show();
                if (loc == null) {
                    try {
                        locationManager.requestLocationUpdates(
                                LocationManager.GPS_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListener);
                        Log.d("GPS Enabled", "GPS Enabled");
                        if (locationManager != null) {
                            loc = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            if (loc != null) {
                                latitude = loc.getLatitude();
                                longitude = loc.getLongitude();
                            }
                        }
                    } catch (SecurityException e) {

                    }
                }
            }*/

        } catch (Exception e) {
            e.printStackTrace();
        }

        return loc;
    }

    public double getLongitude() {
        if (loc != null) {
            longitude = loc.getLongitude();
        }
        return longitude;
    }

    public double getLatitude() {
        if (loc != null) {
            latitude = loc.getLatitude();
        }
        return latitude;
    }

    public boolean canGetLocation() {
        return this.canGetLocation;
    }

    public void showSettingsAlert() {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);


        alertDialog.setTitle("GPS Not Enabled");

        alertDialog.setMessage("Do you wants to turn On GPS");


        alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);
            }
        });


        alertDialog.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });


        alertDialog.show();
    }



    public void stopUsingGPS() {
        if (locationManager != null) {

            locationManager.removeUpdates(TrackGps.this);
        }
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onLocationChanged(Location location) {
            this.loc = location;
            getLocation();
            getLongitude();
            getLatitude();
    }

    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.map.hannah.location3">

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-feature android:name="android.hardware.location.gps" />
    <application


        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <service android:name=".TrackGps" android:enabled="true" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.map.hannah.location3"
        minSdkVersion 17
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
}

---

阅读

getLastKnownLocation

What@commonware shared似乎非常有用，也许这个问题与这个问题完全相同。另外，当没有可用数据时，0.0不是默认位置吗？问题是我没有收到任何错误消息，例如NullPointerException。原始代码来自。不过我的控制台看起来不错。