Android How to - Get location with GPS
The following code shows how to Get location with GPS.
Example
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.java2s.myapplication3.app" > <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="java2s.com" android:theme="@style/AppTheme" > <activity android:name="com.java2s.myapplication3.app.MainActivity" android:label="java2s.com" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
Main layout xml file
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center_horizontal" android:orientation="vertical"> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="20dp" android:layout_marginTop="5dp" android:textAppearance="?android:attr/textAppearanceLarge" /> <ScrollView android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_margin="5dp" android:orientation="vertical"> <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center_horizontal" android:orientation="vertical"> <TextView android:id="@+id/detail" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="5dp" android:layout_marginTop="30dp" android:textAppearance="?android:attr/textAppearanceMedium" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="2dp" android:layout_marginTop="30dp" android:text="GPS Events:" android:textAppearance="?android:attr/textAppearanceSmall" /> <TextView android:id="@+id/gps_events" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginTop="1dp" android:textAppearance="?android:attr/textAppearanceSmall" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="2dp" android:layout_marginTop="10dp" android:text="GPS Satellite Status:" android:textAppearance="?android:attr/textAppearanceSmall" /> <TextView android:id="@+id/satellite_status" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="10dp" android:layout_marginTop="1dp" android:textAppearance="?android:attr/textAppearanceSmall" /> </LinearLayout> </ScrollView> </LinearLayout>
Main Activity Java code
package com.java2s.myapplication3.app; /* ww w. j a va 2 s . c o m*/ import android.app.Activity; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.location.GpsSatellite; import android.location.GpsStatus; import android.location.LocationManager; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.provider.Settings; import android.util.Log; import android.widget.TextView; import android.location.Criteria; import android.location.Location; import android.location.LocationListener; import android.location.LocationManager; import android.location.LocationProvider; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; public class MainActivity extends Activity { public static final String LOC_DATA = "LOC_DATA"; private LocationManager locationMgr; private GpsListener gpsListener; private GpsStatus gpsStatus; private Handler handler; private TextView title; private TextView detail; private TextView gpsEvents; private TextView satelliteStatus; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); title = (TextView) findViewById(R.id.title); detail = (TextView) findViewById(R.id.detail); gpsEvents = (TextView) findViewById(R.id.gps_events); satelliteStatus = (TextView) findViewById(R.id.satellite_status); title.setText("Get current location via GPS"); detail.setText("Attempting to get current location...\n (may take a few seconds)"); locationMgr = (LocationManager) getSystemService(Context.LOCATION_SERVICE); gpsListener = new GpsListener(); handler = new Handler() { public void handleMessage(Message m) { Log.d("log", "Handler returned with message: " + m.toString()); if (m.what == LocationHelper.MESSAGE_CODE_LOCATION_FOUND) { detail.setText("HANDLER RETURNED\nlat:" + m.arg1 + "\nlon:" + m.arg2); } else if (m.what == LocationHelper.MESSAGE_CODE_LOCATION_NULL) { detail.setText("HANDLER RETURNED\nunable to get location"); } else if (m.what == LocationHelper.MESSAGE_CODE_PROVIDER_NOT_PRESENT) { detail.setText("HANDLER RETURNED\nprovider not present"); } } }; } @Override protected void onResume() { super.onResume(); // determine if GPS is enabled or not, if not prompt user to enable it if (!locationMgr.isProviderEnabled(android.location.LocationManager.GPS_PROVIDER)) { AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle("GPS is not enabled") .setMessage("Would you like to go the location settings and enable GPS?").setCancelable(true) .setPositiveButton("Yes", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { startActivity(new Intent(Settings.ACTION_SECURITY_SETTINGS)); } }).setNegativeButton("No", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { dialog.cancel(); finish(); } }); AlertDialog alert = builder.create(); alert.show(); } else { LocationHelper locationHelper = new LocationHelper(locationMgr, handler, "log"); locationHelper.getCurrentLocation(30); } locationMgr.addGpsStatusListener(gpsListener); } @Override protected void onPause() { super.onPause(); locationMgr.removeGpsStatusListener(gpsListener); } // you can also use a GpsListener to be notified when the GPS is started/stopped, and when first "fix" is obtained private class GpsListener implements GpsStatus.Listener { public void onGpsStatusChanged(int event) { Log.d("GpsListener", "Status changed to " + event); switch (event) { case GpsStatus.GPS_EVENT_STARTED: gpsEvents.setText("GPS_EVENT_STARTED"); break; case GpsStatus.GPS_EVENT_STOPPED: gpsEvents.setText("GPS_EVENT_STOPPED"); break; // GPS_EVENT_SATELLITE_STATUS will be called frequently // all satellites in use will invoke it, don't rely on it alone case GpsStatus.GPS_EVENT_SATELLITE_STATUS: // this is *very* chatty, only very advanced use cases should need this (avoid it if you don't need it) gpsStatus = locationMgr.getGpsStatus(gpsStatus); StringBuilder sb = new StringBuilder(); for (GpsSatellite sat : gpsStatus.getSatellites()) { sb.append("Satellite N:" + sat.getPrn() + " AZ:" + sat.getAzimuth() + " EL:" + sat.getElevation() + " S/N:" + sat.getSnr() + "\n"); } satelliteStatus.setText(sb.toString()); break; case GpsStatus.GPS_EVENT_FIRST_FIX: gpsEvents.setText("GPS_EVENT_FIRST_FIX"); break; } } } } /** * Helper class to encapsulate some of the common code needed to determine the * current location using FINE (GPS) provider. * <p/> * If the most recent location is available for the FINE provider, and it is relatively * recent (within FIX_RECENT_BUFFER_TIME -- currently 30 seconds), it is returned back to * the caller using a Message indicating the results. * <p/> * IF the most recent location is either not available, or too old to be used, the * a LocationListener is kicked off for a specified duration. Once the LocationListener * either gets a good Location update, or the time is elapsed, a Message is sent back * to the caller indicating the results. * <p/> * Example usage from an Activity: * <p/> * <pre> * * Handler handler = new Handler() { * public void handleMessage(Message m) { * Log.d(LOG_TAG, "Handler returned with message: " + m.toString()); * if (m.what == LocationHelper.MESSAGE_CODE_LOCATION_FOUND) { * Toast.makeText(Activity.this, "HANDLER RETURNED -- lat:" + m.arg1 + " lon:" + m.arg2, Toast.LENGTH_SHORT) * .show(); * } else if (m.what == LocationHelper.MESSAGE_CODE_LOCATION_NULL) { * Toast.makeText(Activity.this, "HANDLER RETURNED -- unable to get location", Toast.LENGTH_SHORT).show(); * } else if (m.what == LocationHelper.MESSAGE_CODE_PROVIDER_NOT_PRESENT) { * Toast.makeText(Activity.this, "HANDLER RETURNED -- provider not present", Toast.LENGTH_SHORT).show(); * } * } * }; * * LocationHelper helper = new LocationHelper(locationManager, handler, LOG_TAG); * helper.getCurrentLocation(handler); * </pre> * * @author ccollins */ class LocationHelper { public static final int MESSAGE_CODE_LOCATION_FOUND = 1; public static final int MESSAGE_CODE_LOCATION_NULL = 2; public static final int MESSAGE_CODE_PROVIDER_NOT_PRESENT = 3; private static final int FIX_RECENT_BUFFER_TIME = 30000; private LocationManager locationMgr; private LocationListener locationListener; private Handler handler; private Runnable handlerCallback; private String providerName; private String logTag; /** * Construct with a LocationManager, and a Handler to pass back Messages via. * * @param locationMgr * @param handler */ public LocationHelper(LocationManager locationMgr, Handler handler, String logTag) { this.locationMgr = locationMgr; this.locationListener = new LocationListenerImpl(); this.handler = handler; this.handlerCallback = new Thread() { public void run() { endListenForLocation(null); } }; Criteria criteria = new Criteria(); // use Criteria to get provider (and could use COARSE, but doesn't work in emulator) // (FINE will use EITHER network/gps, whichever is the best enabled match, except in emulator must be gps) // (NOTE: network won't work unless enabled - Settings->Location & Security Settings->Use wireless networks) criteria.setAccuracy(Criteria.ACCURACY_FINE); this.providerName = locationMgr.getBestProvider(criteria, true); this.logTag = logTag; } /** * Invoke the process of getting the current Location. * Expect Messages to be returned via the Handler passed in at construction with results. * * @param durationSeconds amount of time to poll for location updates */ public void getCurrentLocation(int durationSeconds) { if (this.providerName == null) { // return 2/0/0 if provider is not enabled Log.d(logTag, "Location provideName null, provider is not enabled or not present."); sendLocationToHandler(MESSAGE_CODE_PROVIDER_NOT_PRESENT, 0, 0); return; } // first check last KNOWN location (and if the fix is recent enough, use it) // NOTE -- this does NOT WORK in the Emulator // (if you send a DDMS "manual" time or geo fix, you get correct DATE, // but fix time starts at 00:00 and seems to increment by 1 second each time sent) // to test this section (getLastLocation being recent enough), you need to use a real device Location lastKnown = locationMgr.getLastKnownLocation(providerName); if (lastKnown != null && lastKnown.getTime() >= (System.currentTimeMillis() - FIX_RECENT_BUFFER_TIME)) { Log.d(logTag, "Last known location recent, using it: " + lastKnown.toString()); // return lastKnown lat/long on Message via Handler sendLocationToHandler(MESSAGE_CODE_LOCATION_FOUND, (int) (lastKnown.getLatitude() * 1e6), (int) (lastKnown.getLongitude() * 1e6)); } else { // last known is relatively old, or doesn't exist, use a LocationListener // and wait for a location update for X seconds Log.d(logTag, "Last location NOT recent, setting up location listener to get newer update."); listenForLocation(providerName, durationSeconds); } } private void sendLocationToHandler(int msgId, int lat, int lon) { Message msg = Message.obtain(handler, msgId, lat, lon); handler.sendMessage(msg); } private void listenForLocation(String providerName, int durationSeconds) { locationMgr.requestLocationUpdates(providerName, 0, 0, locationListener); handler.postDelayed(handlerCallback, durationSeconds * 1000); } private void endListenForLocation(Location loc) { locationMgr.removeUpdates(locationListener); handler.removeCallbacks(handlerCallback); if (loc != null) { sendLocationToHandler(MESSAGE_CODE_LOCATION_FOUND, (int) (loc.getLatitude() * 1e6), (int) (loc.getLongitude() * 1e6)); } else { sendLocationToHandler(MESSAGE_CODE_LOCATION_NULL, 0, 0); } } private class LocationListenerImpl implements LocationListener { @Override public void onStatusChanged(String provider, int status, Bundle extras) { Log.d(logTag, "Location status changed to:" + status); switch (status) { case LocationProvider.AVAILABLE: break; case LocationProvider.TEMPORARILY_UNAVAILABLE: break; case LocationProvider.OUT_OF_SERVICE: endListenForLocation(null); } } @Override public void onLocationChanged(Location loc) { if (loc == null) { return; } Log.d(logTag, "Location changed to:" + loc.toString()); endListenForLocation(loc); } @Override public void onProviderDisabled(String provider) { endListenForLocation(null); } @Override public void onProviderEnabled(String provider) { } } }
