android - getLastKnownLocation 在 Android 中返回 0,0

Question

我正在尝试使用 GPS 简单地返回我当前位置的纬度/经度。无论我做什么，网络和 GPS 的返回都是 0,0。我试过从窗口走过去。

这是我的 GPS 代码:

import android.app.Service;

//
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;


public class TrackGPS extends Service implements LocationListener {

    private final Context mContext;


    boolean checkGPS = false;


    boolean checkNetwork = false;

    boolean canGetLocation = false;

    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);

            // getting GPS status
            checkGPS = locationManager
                    .isProviderEnabled(LocationManager.GPS_PROVIDER);

            // getting network status
            checkNetwork = locationManager
                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if (!checkGPS && !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,
                                0,
                                0, this);
                        Log.d("Network", "Network");
                        if (locationManager != null) {
                            loc = locationManager
                                    .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

                        }

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

                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            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, this);
                        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) {

            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;
            }
            locationManager.removeUpdates(TrackGPS.this);
        }
    }

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

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

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

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }
}

这是我的主要 Activity :

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private Button b_get;
    private TrackGPS gps;
    double longitude;
    double latitude;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b_get = (Button)findViewById(R.id.get);



        b_get.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                gps = new TrackGPS(MainActivity.this);


                if(gps.canGetLocation()){


                    longitude = gps.getLongitude();
                    latitude = gps .getLatitude();

                    Toast.makeText(getApplicationContext(),"Longitude:"+Double.toString(longitude)+"\nLatitude:"+Double.toString(latitude),Toast.LENGTH_SHORT).show();
                }
                else
                {

                    gps.showSettingsAlert();
                }

            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        gps.stopUsingGPS();
    }
}

这是我的 Android list :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.quantums3.getcurrentlocation">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.INTERNET" />

</manifest>

提前致谢。

Answer 1

getLastKnownLocation 在 Android 中返回 0,0

实际上，上述方法在您的情况下返回 null，并且由于您的 TrackGPS 结构，您看到的默认值是 double latitude; double longitude;