android GPS 定位系统源码

package com.wissen.android; import java.util.List; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Point; import android.graphics.drawable.Drawable; import android.location.Location; import android.location.LocationListener; import android.location.LocationManager; import android.os.Bundle; import android.view.KeyEvent; import android.view.ViewGroup; import android.view.ViewGroup.LayoutParams; import android.widget.Button; import android.widget.EditText; import android.widget.ZoomControls; import com.google.android.maps.GeoPoint; import com.google.android.maps.MapActivity; import com.google.android.maps.MapController; import com.google.android.maps.MapView; import com.google.android.maps.Overlay; public class Hello extends MapActivity implements LocationListener { /** Called when the activity is first created. */ EditText txted = null; Button btnSimple = null; MapView gMapView = null; MapController mc = null; Drawable defaultMarker = null; GeoPoint p = null; double latitude = 18.9599990845, longitude = 72.819999694; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Creating TextBox displying Lat, Long txted = (EditText) findViewById(R.id.id1); String currentLocation = "Lat: " + latitude + " Lng: " + longitude; txted.setText(currentLocation); // Creating and initializing Map gMapView = (MapView) findViewById(R.id.myGMap); p = new GeoPoint((int) (latitude * 1000000), (int) (longitude * 1000000)); gMapView.setSatellite(true); mc = gMapView.getController(); mc.setCenter(p); mc.setZoom(14); // Add a location mark MyLocationOverlay myLocationOverlay = new MyLocationOverlay(); List<Overlay> list = gMapView.getOverlays(); list.add(myLocationOverlay); // Adding zoom controls to Map ZoomControls zoomControls = (ZoomControls) gMapView.getZoomControls(); zoomControls.setLayoutParams(new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); gMapView.addView(zoomControls); gMapView.displayZoomControls(true); // Getting locationManager and reflecting changes over map if distance travel by // user is greater than 500m from current location. LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000L, 500.0f, this); } /* This method is called when use position will get changed */ public void onLocationChanged(Location location) { if (location != null) { double lat = location.getLatitude(); double lng = location.getLongitude(); String currentLocation = "Lat: " + lat + " Lng: " + lng; txted.setText(currentLocation); p = new GeoPoint((int) lat * 1000000, (int) lng * 1000000); mc.animateTo(p); } } public void onProviderDisabled(String provider) { // required for interface, not used } public void onProviderEnabled(String provider) { // required for interface, not used } public void onStatusChanged(String provider, int status, Bundle extras) { // required for interface, not used } protected boolean isRouteDisplayed() { // TODO Auto-generated method stub return false; } /* User can zoom in/out using keys provided on keypad */ public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_I) { gMapView.getController().setZoom(gMapView.getZoomLevel() + 1); return true; } else if (keyCode == KeyEvent.KEYCODE_O) { gMapView.getController().setZoom(gMapView.getZoomLevel() - 1); return true; } else if (keyCode == KeyEvent.KEYCODE_S) { gMapView.setSatellite(true); return true; } else if (keyCode == KeyEvent.KEYCODE_T) { gMapView.setTraffic(true); return true; } return false; } /* Class overload draw method which actually plot a marker,text etc. on Map */ protected class MyLocationOverlay extends com.google.android.maps.Overlay { @Override public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) { Paint paint = new Paint(); super.draw(canvas, mapView, shadow); // Converts lat/lng-Point to OUR coordinates on the screen. Point myScreenCoords = new Point(); mapView.getProjection().toPixels(p, myScreenCoords); paint.setStrokeWidth(1); paint.setARGB(255, 255, 255, 255); paint.setStyle(Paint.Style.STROKE); Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.marker); canvas.drawBitmap(bmp, myScreenCoords.x, myScreenCoords.y, paint); canvas.drawText("I am here...", myScreenCoords.x, myScreenCoords.y, paint); return true; } } }