问题
I'm not having any luck receiving any data from the GPS using the code below, and i'm not sure what I'm doing wrong, it seems like my code matches everything i see online. i'd like to eventually add this to a background service to log gps coordinates even when the activity isn't visible or if other apps are open and if the speed is greater than a certain defined amount, but at this point I can't even get any of the data to show up. i'm relatively new to android but i can't figure out what am i doing wrong?
public class MainActivity extends Activity {
TextView textView;
MyLocationListener myLocationListener;
LocationManager lm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.textView = (TextView)findViewById(R.id.message);
addLocationListener();
}
@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;
}
private void addLocationListener()
{
lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Criteria c = new Criteria();
c.setAccuracy(Criteria.ACCURACY_FINE);
final String PROVIDER = lm.getBestProvider(c, true);
this.myLocationListener = new MyLocationListener();
this.lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0L, 0.0F, this.myLocationListener);
//lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0L, 0.0F, myLocationListener);
Log.d("LOC_SERVICE", "Service RUNNING!");
}
public void updateLocation(Location location)
{
double latitude, longitude;
latitude = location.getLatitude();
longitude = location.getLongitude();
int mph = convertSpeed(location.getSpeed());
Log.d("LOC_SERVICE", "mph: "+mph);
this.textView.setText(this.textView.getText()+"\n"+"lat: "+latitude+" lng: "+longitude+" mph: "+mph);
}
private int convertSpeed(float speed) {
int mph =(int)(2.236936D * speed);
return mph;
}
class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location location) {
Log.d("LOC_SERVICE", "Listener RUNNING!");
updateLocation(location);
}
@Override
public void onProviderDisabled(String provider) {}
@Override
public void onProviderEnabled(String provider) {}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
}
}
回答1:
Try following code -
package com.muslimcompanion.utills;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
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.util.Log;
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
public boolean canGetLocation() {
return this.canGetLocation;
}
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
dialog.cancel();
}
});
alertDialog.setCancelable(false);
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
Now put these line into your activity -
GPSTracker gps = new GPSTracker(this);
int status = 0;
if(gps.canGetLocation())
{
status = GooglePlayServicesUtil
.isGooglePlayServicesAvailable(getApplicationContext());
if (status == ConnectionResult.SUCCESS) {
current_lattitude = gps.getLatitude();
current_longitude = gps.getLongitude();
_appPrefs.saveSmsBody("" + current_lattitude);
_appPrefs.saveSmsBody("" + current_longitude);
Log.d("dashlatlongon", "" + current_lattitude + "-"
+ current_longitude);
if (current_lattitude == 0.0 && current_longitude == 0.0) {
current_lattitude = 22.22;
current_longitude = 22.22;
}
} else {
current_lattitude = 22.22;
current_longitude = 22.22;
}
}
else
{
gps.showSettingsAlert();
}
回答2:
You need to use permission first:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
Next you inside onCreate() method use below code to get access to GPS.
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
2000, 1, this);
}
Now if GPS is not enabled then you need to refer below code. For detailed explanation, you can refer how to get[DEAD LINK] [current location in android]1 tutorial.
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
Here we have used intents to redirect user to location settings page so that he can enable the GPS under location settings.
回答3:
you can achieve this easily. you have to write code in main activity. and Main activity implements Locationlistner interface. and overload its four methods. here i'am retrieving my Longitude and Latitide co-ordinates in a textview when application started. and you have to give permission for access location in your manifest file.
as under my code.
package com.nisarg.gpsdemo;
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.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity implements LocationListener {
private LocationManager locationManager;
private TextView textview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textview=(TextView)findViewById(R.id.textView);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
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;
}
Location location = locationManager.getLastKnownLocation(locationManager.NETWORK_PROVIDER);
onLocationChanged(location);
}
@Override
public void onLocationChanged(Location location) {
double longitude=location.getLongitude();
double latitude=location.getLatitude();
textview.setText("Longitude: "+longitude+" Latitide: "+latitude);
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
}
and you have to give permission like this in manifest file.
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
And last warning. you have to give permission to your application and start mobile data and GPS before you open application. either it will be crashed.
that's it. hope it will help you. :)
来源：https://stackoverflow.com/questions/21085497/how-to-use-android-locationmanager-and-listener