总是得不到位置信息

Question

该程序之前正在运行。但现在我不能再获得位置信息了。位置值始终为null。我很高兴得到你的帮助！非常感谢你！

mainActivity.jave

package com.example.a12086.map;


import android.location.Location;

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.Toast;

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;


public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    private GPS gps;
    private Location mlocation;
    private EditText input;
    double longitude;
    double latitude;

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


        input = (EditText) findViewById(R.id.Edittext);
        gps=new GPS(getApplicationContext());
        mlocation=gps.getLocation();
        if(mlocation==null)
        {
            Toast.makeText(getApplicationContext(),"something wrong",Toast.LENGTH_LONG).show();
        }
        else{
            latitude=mlocation.getLatitude();
            longitude=mlocation.getLongitude();
        }

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        LatLng Myposition = new LatLng(latitude,longitude);
        mMap.addMarker(new MarkerOptions().position(Myposition).title("My Position"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(Myposition));
    }


}

GPS.java

package com.example.a12086.map;

import android.Manifest;
import android.app.Service;
import android.content.Context;
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.support.v4.content.ContextCompat;

public class GPS extends Service implements LocationListener {
    private final Context context;
    boolean isGPSEnabled=false;
    boolean isNETWORKEnable=false;
    boolean canGetLocation=false;

    Location location;
    protected LocationManager locationManager;
    public GPS (Context context){
        this.context=context;
    }
    public Location getLocation(){
        try {
            locationManager = (LocationManager) context.getSystemService(LOCATION_SERVICE);
            isGPSEnabled = locationManager.isProviderEnabled(locationManager.GPS_PROVIDER);
            isNETWORKEnable = locationManager.isProviderEnabled(locationManager.NETWORK_PROVIDER);
            if (ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
                    || ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                if (isGPSEnabled) {
                    if (location == null) {
                        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, this);
                        if (locationManager == null) {
                            location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        }
                    }
                }
                if (location == null) {
                    if (isNETWORKEnable) {
                        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000, 0, this);
                        if (locationManager == null) {
                            location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                        }
                    }
                }
            }
        }catch(Exception ex){
        }
        return location;
    }
    public void onLocationChanged(Location location) {
    }
    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
    }
    @Override
    public void onProviderEnabled(String provider) {
    }
    @Override
    public void onProviderDisabled(String provider) {
    }
    public IBinder onBind(Intent arg0){
        return null;
    }
}

logcat的

04-27 17:51:42.930 6663-6854/com.example.a12086.map I/OpenGLRenderer: Initialized EGL, version 1.4
04-27 17:51:42.935 6663-6854/com.example.a12086.map W/linker: /vendor/lib64/libhwuibp.so: unused DT entry: type 0xf arg 0xe3a
04-27 17:51:42.949 6663-6830/com.example.a12086.map E/BufferQueueProducer: [SurfaceTexture-0-6663-0] connect: already connected (cur=1 req=1)
04-27 17:51:42.962 6663-6854/com.example.a12086.map E/OpenGLRenderer: allen debug liyu Key: 0
04-27 17:51:42.965 6663-6854/com.example.a12086.map E/OpenGLRenderer: allen debug liyu Key: 5242945
04-27 17:51:42.966 6663-6854/com.example.a12086.map E/OpenGLRenderer: allen debug liyu Key: 5242944
04-27 17:51:42.989 6663-6854/com.example.a12086.map E/OpenGLRenderer: allen debug liyu Key: 1
04-27 17:51:43.026 6663-6854/com.example.a12086.map E/OpenGLRenderer: allen debug liyu Key: 824633720832
04-27 17:51:44.873 6663-6836/com.example.a12086.map W/DynamiteModule: Local module descriptor class for com.google.android.gms.googlecertificates not found.
04-27 17:51:44.885 6663-6836/com.example.a12086.map I/DynamiteModule: Considering local module com.google.android.gms.googlecertificates:0 and remote module com.google.android.gms.googlecertificates:2
04-27 17:51:44.885 6663-6836/com.example.a12086.map I/DynamiteModule: Selected remote version of com.google.android.gms.googlecertificates, version >= 2
04-27 17:52:16.559 6663-6663/com.example.a12086.map W/IInputConnectionWrapper: finishComposingText on inactive InputConnection
04-27 17:53:03.234 6663-6663/com.example.a12086.map W/IInputConnectionWrapper: finishComposingText on inactive InputConnection
04-27 17:53:03.240 6663-6830/com.example.a12086.map E/BufferQueueProducer: [SurfaceTexture-0-6663-1] connect: already connected (cur=1 req=1)
04-27 17:53:04.791 6663-6663/com.example.a12086.map W/IInputConnectionWrapper: reportFullscreenMode on inexistent InputConnection
04-27 17:53:04.791 6663-6663/com.example.a12086.map W/IInputConnectionWrapper: finishComposingText on inactive InputConnection