在android中使用google map api时无法更新位置

Question

我想在我的应用中使用谷歌地图集成。我使用 location manager 和 location listener 来更新当前用户位置。但是位置监听器在我的代码中不起作用。感谢期待的帮助。

请有人告诉我为什么我的位置监听器没有给出当前位置并且在调用位置manager.getLastKnownLocation() 时它每次都返回 null。

Java 代码：

package com.example.administrator.uber_clone;

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.util.Log;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import java.util.Map;

public class PassengerActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    private LocationManager locationManager;
    private LocationListener locationListener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_passenger);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }


    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {

                Log.i("TAG",""+location);

                settingUpdateLocationToMap(location);
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {

            }
        };
        checksForAndroidVersion();
        // Add a marker in Sydney and move the camera
        //settingUpdateLocationToMap();
        //   Location location = getCurrentLocation();


    }

    private void checksForAndroidVersion() {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {

            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
            if (locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER) != null) {
                Location passangerLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                settingUpdateLocationToMap(passangerLocation);
            }
        } else {
            checksThatLocationGiven();
        }

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == 1000 && grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
//                getCurrentLocation();
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
                if (locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER) != null) {
                    Location passangerLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                    settingUpdateLocationToMap(passangerLocation);
                }

            }
            Log.i("onRequest", "" + requestCode);
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    private void checksThatLocationGiven() {

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1000);
        } else {
//            getCurrentLocation();
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
            if (locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER) != null) {
                Location passangerLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                settingUpdateLocationToMap(passangerLocation);
            }

        }
    }
//    private Location getCurrentLocation(){
//
//        Location passangerLocation = null;
//        try {
//            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
//            passangerLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
//            settingUpdateLocationToMap(passangerLocation);
//
//        } catch (SecurityException e) {
//            Log.i("error",e.getMessage());
//        }
//
//        return passangerLocation;
//    }

    private void settingUpdateLocationToMap(Location location) {
        LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
        mMap.clear();
        mMap.addMarker(new MarkerOptions().position(latLng).title("You are here"));
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 10));
        Log.i("latlong", latLng + "");
    }
}

清单文件：

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

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

    <!--
         The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
         Google Maps Android API v2, but you must specify either coarse or fine
         location permissions for the 'MyLocation' functionality. 
    -->
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <application
        android:name=".App"
        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"
        tools:ignore="GoogleAppIndexingWarning">
        <activity android:name=".SignUpActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

        <meta-data
            android:name="com.parse.SERVER_URL"
            android:value="@string/back4app_server_url" />
        <meta-data
            android:name="com.parse.APPLICATION_ID"
            android:value="@string/back4app_app_id" />
        <meta-data
            android:name="com.parse.CLIENT_KEY"
            android:value="@string/back4app_client_key" />
        <!--
             The API key for Google Maps-based APIs is defined as a string resource.
             (See the file "res/values/google_maps_api.xml").
             Note that the API key is linked to the encryption key used to sign the APK.
             You need a different API key for each encryption key, including the release key that is used to
             sign the APK for publishing.
             You can define the keys for the debug and release targets in src/debug/ and src/release/. 
        -->
        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="@string/google_maps_key" />

        <activity
            android:name=".PassengerActivity"
            android:label="@string/title_activity_passenger"></activity>
        <uses-library
            android:name="org.apache.http.legacy"
            android:required="false" />
    </application>

</manifest>

Answer 1

了解谷歌开发者地图文档

解决方案： 需要在清单文件中添加