Android上的LocationManager
API彷佛對於只須要偶爾粗略估計用戶位置的應用程序來講有點麻煩。 android
我正在使用的應用程序自己並非真正的位置應用程序,可是它確實須要獲取用戶的位置才能顯示附近商家的列表。 無需擔憂用戶是否四處走動或相似的事情。 git
這是我想作的: canvas
Activity
X中須要時可使用它。 彷佛不該該那麼難,可是在我看來,我不得不啓動兩個不一樣的位置提供程序(GPS和網絡)並管理每一個生命週期。 不只如此,我還必須在多個活動中重複相同的代碼才能知足#2的要求。 過去我曾嘗試使用getBestProvider()
將解決方案縮減爲僅使用一個位置提供程序,但這彷佛只爲您提供最佳的「理論」提供程序,而不是實際上會爲您提供最佳結果的提供程序。 api
有沒有更簡單的方法能夠作到這一點? 網絡
使用如下代碼,它將爲您提供最佳的提供程序: ide
String locCtx = Context.LOCATION_SERVICE; LocationManager locationMgr = (LocationManager) ctx.getSystemService(locCtx); Criteria criteria = new Criteria(); criteria.setAccuracy(Criteria.ACCURACY_FINE); criteria.setAltitudeRequired(false); criteria.setBearingRequired(false); criteria.setCostAllowed(true); criteria.setPowerRequirement(Criteria.POWER_LOW); String provider = locationMgr.getBestProvider(criteria, true); System.out.println("Best Available provider::::"+provider);
我建立了一個帶有逐步說明的小型應用程序,以獲取當前位置的GPS座標。 post
如下網址中包含完整的示例源代碼: fetch
看看它怎麼運做 : this
咱們要作的就是在清單文件中添加此權限
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"> </uses-permission>
並像這樣建立LocationManager實例
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
檢查GPS是否啓用
而後實現LocationListener和獲取座標
LocationListener locationListener = new MyLocationListener(); locationManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 5000, 10, locationListener);
這是示例代碼
/*----------Listener class to get coordinates ------------- */ private class MyLocationListener implements LocationListener { @Override public void onLocationChanged(Location loc) { editLocation.setText(""); pb.setVisibility(View.INVISIBLE); Toast.makeText( getBaseContext(), "Location changed: Lat: " + loc.getLatitude() + " Lng: " + loc.getLongitude(), Toast.LENGTH_SHORT).show(); String longitude = "Longitude: " + loc.getLongitude(); Log.v(TAG, longitude); String latitude = "Latitude: " + loc.getLatitude(); Log.v(TAG, latitude); /*-------to get City-Name from coordinates -------- */ String cityName = null; Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault()); List<Address> addresses; try { addresses = gcd.getFromLocation(loc.getLatitude(), loc.getLongitude(), 1); if (addresses.size() > 0) System.out.println(addresses.get(0).getLocality()); cityName = addresses.get(0).getLocality(); } catch (IOException e) { e.printStackTrace(); } String s = longitude + "\n" + latitude + "\n\nMy Current City is: " + cityName; editLocation.setText(s); } @Override public void onProviderDisabled(String provider) {} @Override public void onProviderEnabled(String provider) {} @Override public void onStatusChanged(String provider, int status, Bundle extras) {} }
這是提供用戶當前位置的代碼
建立地圖活動:
public class Maps extends MapActivity { public static final String TAG = "MapActivity"; private MapView mapView; private LocationManager locationManager; Geocoder geocoder; Location location; LocationListener locationListener; CountDownTimer locationtimer; MapController mapController; MapOverlay mapOverlay = new MapOverlay(); @Override protected void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); initComponents(); mapView.setBuiltInZoomControls(true); mapView.setSatellite(true); mapView.setTraffic(true); mapView.setStreetView(true); mapController = mapView.getController(); mapController.setZoom(16); locationManager = (LocationManager) getSystemService(LOCATION_SERVICE); if (locationManager == null) { Toast.makeText(Maps.this, "Location Manager Not Available", Toast.LENGTH_SHORT).show(); return; } location = locationManager .getLastKnownLocation(LocationManager.GPS_PROVIDER); if (location == null) location = locationManager .getLastKnownLocation(LocationManager.NETWORK_PROVIDER); if (location != null) { double lat = location.getLatitude(); double lng = location.getLongitude(); Toast.makeText(Maps.this, "Location Are" + lat + ":" + lng, Toast.LENGTH_SHORT).show(); GeoPoint point = new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6)); mapController.animateTo(point, new Message()); mapOverlay.setPointToDraw(point); List<Overlay> listOfOverlays = mapView.getOverlays(); listOfOverlays.clear(); listOfOverlays.add(mapOverlay); } locationListener = new LocationListener() { public void onStatusChanged(String arg0, int arg1, Bundle arg2) {} public void onProviderEnabled(String arg0) {} public void onProviderDisabled(String arg0) {} public void onLocationChanged(Location l) { location = l; locationManager.removeUpdates(this); if (l.getLatitude() == 0 || l.getLongitude() == 0) { } else { double lat = l.getLatitude(); double lng = l.getLongitude(); Toast.makeText(Maps.this, "Location Are" + lat + ":" + lng, Toast.LENGTH_SHORT).show(); } } }; if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) locationManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 1000, 10f, locationListener); locationManager.requestLocationUpdates( LocationManager.NETWORK_PROVIDER, 1000, 10f, locationListener); locationtimer = new CountDownTimer(30000, 5000) { @Override public void onTick(long millisUntilFinished) { if (location != null) locationtimer.cancel(); } @Override public void onFinish() { if (location == null) { } } }; locationtimer.start(); } public MapView getMapView() { return this.mapView; } private void initComponents() { mapView = (MapView) findViewById(R.id.map_container); ImageView ivhome = (ImageView) this.findViewById(R.id.imageView_home); ivhome.setOnClickListener(new OnClickListener() { public void onClick(View arg0) { // TODO Auto-generated method stub Intent intent = new Intent(Maps.this, GridViewContainer.class); startActivity(intent); finish(); } }); } @Override protected boolean isRouteDisplayed() { return false; } class MapOverlay extends Overlay { private GeoPoint pointToDraw; public void setPointToDraw(GeoPoint point) { pointToDraw = point; } public GeoPoint getPointToDraw() { return pointToDraw; } @Override public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) { super.draw(canvas, mapView, shadow); Point screenPts = new Point(); mapView.getProjection().toPixels(pointToDraw, screenPts); Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.select_map); canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 24, null); return true; } } }
main.xml:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@android:color/black" android:orientation="vertical" > <com.google.android.maps.MapView android:id="@+id/map_container" android:layout_width="fill_parent" android:layout_height="fill_parent" android:apiKey="yor api key" android:clickable="true" android:focusable="true" /> </LinearLayout>
並在清單中定義如下權限:
<uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
public static Location getBestLocation(Context ctxt) { Location gpslocation = getLocationByProvider( LocationManager.GPS_PROVIDER, ctxt); Location networkLocation = getLocationByProvider( LocationManager.NETWORK_PROVIDER, ctxt); Location fetchedlocation = null; // if we have only one location available, the choice is easy if (gpslocation != null) { Log.i("New Location Receiver", "GPS Location available."); fetchedlocation = gpslocation; } else { Log.i("New Location Receiver", "No GPS Location available. Fetching Network location lat=" + networkLocation.getLatitude() + " lon =" + networkLocation.getLongitude()); fetchedlocation = networkLocation; } return fetchedlocation; } /** * get the last known location from a specific provider (network/gps) */ private static Location getLocationByProvider(String provider, Context ctxt) { Location location = null; // if (!isProviderSupported(provider)) { // return null; // } LocationManager locationManager = (LocationManager) ctxt .getSystemService(Context.LOCATION_SERVICE); try { if (locationManager.isProviderEnabled(provider)) { location = locationManager.getLastKnownLocation(provider); } } catch (IllegalArgumentException e) { Log.i("New Location Receiver", "Cannot access Provider " + provider); } return location; }
簡單而最佳的地理位置定位方法。
LocationManager lm = null; boolean network_enabled; if (lm == null) lm = (LocationManager) Kikit.this.getSystemService(Context.LOCATION_SERVICE); network_enabled = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER); dialog = ProgressDialog.show(Kikit.this, "", "Fetching location...", true); final Handler handler = new Handler(); timer = new Timer(); TimerTask doAsynchronousTask = new TimerTask() { @Override public void run() { handler.post(new Runnable() { @Override public void run() { Log.e("counter value","value "+counter); if(counter<=8) { try { counter++; if (network_enabled) { lm = (LocationManager) Kikit.this.getSystemService(Context.LOCATION_SERVICE); Log.e("in network_enabled..","in network_enabled"); // Define a listener that responds to location updates LocationListener locationListener = new LocationListener() { public void onLocationChanged(Location location) { if(attempt == false) { attempt = true; Log.e("in location listener..","in location listener.."); longi = location.getLongitude(); lati = location.getLatitude(); Data.longi = "" + longi; Data.lati = "" + lati; Log.e("longitude : ",""+longi); Log.e("latitude : ",""+lati); if(faceboo_name.equals("")) { if(dialog!=null){ dialog.cancel();} timer.cancel(); timer.purge(); Data.homepage_resume = true; lm = null; Intent intent = new Intent(); intent.setClass(Kikit.this,MainActivity.class); startActivity(intent); finish(); } else { isInternetPresent = cd.isConnectingToInternet(); if (isInternetPresent) { if(dialog!=null) dialog.cancel(); Showdata(); } else { error_view.setText(Data.internet_error_msg); error_view.setVisibility(0); error_gone(); } } } } public void onStatusChanged(String provider, int status, Bundle extras) { } public void onProviderEnabled(String provider) { //Toast.makeText(getApplicationContext(), "Location enabled", Toast.LENGTH_LONG).show(); } public void onProviderDisabled(String provider) { } }; // Register the listener with the Location Manager to receive // location updates lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 100000, 10,locationListener); } else{ //Toast.makeText(getApplicationContext(), "No Internet Connection.", 2000).show(); buildAlertMessageNoGps(); } } catch (Exception e) { // TODO // Auto-generated // catch // block } } else { timer.purge(); timer.cancel(); if(attempt == false) { attempt = true; String locationProvider = LocationManager.NETWORK_PROVIDER; // Or use LocationManager.GPS_PROVIDER try { Location lastKnownLocation = lm.getLastKnownLocation(locationProvider); longi = lastKnownLocation.getLongitude(); lati = lastKnownLocation.getLatitude(); Data.longi = "" + longi; Data.lati = "" + lati; } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); Log.i("exception in loc fetch", e.toString()); } Log.e("longitude of last known location : ",""+longi); Log.e("latitude of last known location : ",""+lati); if(Data.fb_access_token == "") { if(dialog!=null){ dialog.cancel();} timer.cancel(); timer.purge(); Data.homepage_resume = true; Intent intent = new Intent(); intent.setClass(Kikit.this,MainActivity.class); startActivity(intent); finish(); } else { isInternetPresent = cd.isConnectingToInternet(); if (isInternetPresent) { if(dialog!=null){ dialog.cancel();} Showdata(); } else { error_view.setText(Data.internet_error_msg); error_view.setVisibility(0); error_gone(); } } } } } }); } }; timer.schedule(doAsynchronousTask, 0, 2000); private void buildAlertMessageNoGps() { final AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setMessage("Your WiFi & mobile network location is disabled , do you want to enable it?") .setCancelable(false) .setPositiveButton("Yes", new DialogInterface.OnClickListener() { public void onClick(@SuppressWarnings("unused") final DialogInterface dialog, @SuppressWarnings("unused") final int id) { startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS)); setting_page = true; } }) .setNegativeButton("No", new DialogInterface.OnClickListener() { public void onClick(final DialogInterface dialog, @SuppressWarnings("unused") final int id) { dialog.cancel(); finish(); } }); final AlertDialog alert = builder.create(); alert.show(); }