如何在我的Android应用程序中实现位置监听器？

Question

我正在创建一个使用谷歌地图API的应用程序，它运行正常，但它没有提供我当前的位置。我认为错误是在If条件中的miUbicacion方法，但我不知道该怎么做。请帮助我，这是MainActivity的代码：

package com.example.android.parking;

import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.app.ActivityCompat;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.UiSettings;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;

import static com.example.android.parking.R.id.map;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener, OnMapReadyCallback {

    private GoogleMap mMap;
    Location location;

    private Marker marcador;

    double lat = 3.43722;
    double lngt = -76.5225;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        MapFragment mapFragment = (MapFragment) getFragmentManager()
                .findFragmentById(map);
        mapFragment.getMapAsync(this);


        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_reservas) {
            // Handle the camera action
        } else if (id == R.id.historial_reservas) {

        } else if (id == R.id.metodos_de_pago) {

        } else if (id == R.id.promociones) {

        } else if (id == R.id.opciones) {

        } else if (id == R.id.ayuda) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }


    @Override
    public void onMapReady(GoogleMap googleMap) {


        mMap = googleMap;

        mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);

        miUbicacion();


        UiSettings zoomControls = mMap.getUiSettings();
        zoomControls.setZoomControlsEnabled(true);

        UiSettings locationButton = mMap.getUiSettings();
        locationButton.setMyLocationButtonEnabled(true);
    }

    private void agregarMarcador(double lat, double lngt) {
        LatLng coordenadas = new LatLng(lat, lngt);
        CameraUpdate miUbicacion = CameraUpdateFactory.newLatLngZoom(coordenadas, 25);
        if (marcador != null) marcador.remove();
        marcador = mMap.addMarker(new MarkerOptions()
                .position(coordenadas)
                .title("I'm here")
                .icon(BitmapDescriptorFactory.fromResource(R.id.icon_only)));
        mMap.animateCamera(miUbicacion);
    }

    private void actualizarUbicacion(Location location) {
        if (location != null) {
            lat = location.getLatitude();
            lngt = location.getLongitude();
            agregarMarcador(lat, lngt);
            Log.d("responseAns", "funciona metodo" + lat + lngt);
        }
    }

    LocationListener locListener = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            actualizarUbicacion(location);
        }

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

        }

        @Override
        public void onProviderEnabled(String provider) {
            Log.d("responseAns", "Gps activado");
        }

        @Override
        public void onProviderDisabled(String provider) {
            Log.d("responseAns", "GPS desactivado");
        }
    };

    private void miUbicacion() {
        if (ActivityCompat.checkSelfPermission
                (this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission
                (this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }

        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        actualizarUbicacion(location);
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,5000,0,locListener);
    }
}

这是我的清单文件：

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

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

    <permission android:name="com.example.android.parking.permission.MAPS_RECEIVE"
        android:protectionLevel="signature"/>
    <uses-permission android:name="com.example.android.parking.permission.MAPS_RECEIVE"/>

    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true">
    </uses-feature>

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

        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="@string/google_maps_key" />

        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

那是我的MainActivity XML文件：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start"
    tools:context=".MainActivity">

    <fragment xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="com.google.android.gms.maps.MapFragment" />

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

</android.support.v4.widget.DrawerLayout>