获取纬度经度失败

Question

我的代码有两个问题

1. 无法进入onLocationChanged()函数
2. mylocation 始终为空

我还添加了权限并打开了我的设备 GPS 功能

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

以下是我的代码，请帮助我获取纬度经度谢谢大家。

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

        Getaddress getaddress = new Getaddress();
        getaddress.excute();
    }

    public class Getaddress implements LocationListener {
        Geocoder geocoder;
        private Location mylocation;
        private double Latitude;
        private double Lontitude;
        private LocationManager locationManager;



        public Getaddress() {
            locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

            Criteria criteria = new Criteria();
            String provider = locationManager.getBestProvider(criteria, true);
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0, this);
            mylocation = locationManager.getLastKnownLocation(provider);

            Boolean isGPSEnabled = locationManager
                    .isProviderEnabled(LocationManager.GPS_PROVIDER);

            Log.w("isGPSEnabled",isGPSEnabled.toString());

        }

        public void excute()
        {
            Latitude = mylocation.getLatitude();
            Lontitude = mylocation.getLongitude();
            Toast.makeText(SecondActivity.this, "Latitude"+Double.toString(Latitude),Toast.LENGTH_LONG).show();
        }

        @Override
        public void onLocationChanged(Location location)
        {
            mylocation = location;
        }

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

        }

        @Override
        public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {

        }



    }

Answer 1

Xml 文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/tv_location"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:text="@string/str_tv_location"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/tv_longitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tv_location"
        android:layout_centerHorizontal="true" />

    <TextView
        android:id="@+id/tv_latitude"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/tv_longitude"
        android:layout_centerHorizontal="true"/>
</RelativeLayout>

Java 文件：

import android.app.Activity;
import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.Menu;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements LocationListener{

    LocationManager locationManager ;
    String provider;

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

        // Getting LocationManager object
        locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);

        // Creating an empty criteria object
        Criteria criteria = new Criteria();

        // Getting the name of the provider that meets the criteria
        provider = locationManager.getBestProvider(criteria, false);

        if(provider!=null && !provider.equals("")){

            // Get the location from the given provider
            Location location = locationManager.getLastKnownLocation(provider);

            locationManager.requestLocationUpdates(provider, 20000, 1, this);

            if(location!=null)
                onLocationChanged(location);
            else
                Toast.makeText(getBaseContext(), "Location can't be retrieved", Toast.LENGTH_SHORT).show();

        }else{
            Toast.makeText(getBaseContext(), "No Provider Found", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    @Override
    public void onLocationChanged(Location location) {
        // Getting reference to TextView tv_longitude
        TextView tvLongitude = (TextView)findViewById(R.id.tv_longitude);

        // Getting reference to TextView tv_latitude
        TextView tvLatitude = (TextView)findViewById(R.id.tv_latitude);

        // Setting Current Longitude
        tvLongitude.setText("Longitude:" + location.getLongitude());

        // Setting Current Latitude
        tvLatitude.setText("Latitude:" + location.getLatitude() );
    }

    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub
    }
}

权限：-

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

Answer 2

---

• 首先：您需要 GPS 可用空间。
  
• 其次：您的位置始终为空，因为您的 GRP LOCATION 空间不可用。您需要检查 GPS 是否工作
  

onLocationChanged 方法在您的位置发生变化时起作用。

 public class GPSTracker implements LocationListener {


    public GPSTracker(Context con){
        LocationManager lm = (LocationManager) con.getSystemService(Context.LOCATION_SERVICE);
        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
    }

    @Override
    public void onLocationChanged(Location location) {
        if (location != null) {
            // do something here...
            //location.getLatitude();
            //location.getLongitude();
        }
    }

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

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }
}