我在下面的这个MapActivity类中显示了一张地图并放置了用户当前位置的图钉。另一方面，我有一个对象类 VideoLocation，它具有从服务器的 JSON 文件中提取的某些地方的纬度和经度。我还想在地图上用大头针绘制位置。
我怎么能做到这一点？我需要在下面的课程中添加什么？
仅供参考，这就是我在我的 ListActivity 上调用对象的纬度和经度的方式：
VideoLocation vidLocation = videoLocations[position];
double lat2 = vidLocation.latitude;
double lng2 = vidLocation.longitude;
这堂课：
public class MyMapActivity extends MapActivity implements OnClickListener {
public static final String TAG = "GoogleMapsActivity";
private MapView mapView;
private LocationManager locationManager;
Geocoder geocoder;
Location location;
LocationListener locationListener;
CountDownTimer locationtimer;
MapController mapController;
MapOverlay mapOverlay = new MapOverlay();
private VideoLocation[] videoLocations = null;
@Override
protected void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.my_map_activity);
initComponents();
JsonDB dbhelper = new JsonDB(MyMapActivity.this);
SQLiteDatabase db = dbhelper.getWritableDatabase();
db.beginTransaction();
videoLocations = dbhelper.getVideoLocations(db);
db.setTransactionSuccessful();//end transaction
db.endTransaction();
db.close();
final ImageButton refresh = (ImageButton) findViewById(R.id.btn_nav_impressum);
refresh.setOnClickListener(this);
final ImageButton search =(ImageButton) findViewById(R.id.btn_nav_locater);
search.setOnClickListener(this);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
if (locationManager == null) {
Toast.makeText(MyMapActivity.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) {
animateMap(location);
List<Overlay> listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);
}
locationListener = new LocationListener() {
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
}
@Override
public void onProviderEnabled(String arg0) {
}
@Override
public void onProviderDisabled(String arg0) {
}
@Override
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();
showAddress(lat,lng);
}
}
};
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 void animateMap(Location location){
double lat = location.getLatitude();
double lng = location.getLongitude();
GeoPoint point = new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6));
GeoPoint point2 = new GeoPoint((int) (lat2 * 1E6), (int) (lng2 * 1E6));
mapController.animateTo(point, new Message());
mapOverlay.setPointToDraw(point);
}
public MapView getMapView() {
return this.mapView;
}
private void initComponents() {
mapView = (MapView) findViewById(R.id.mapView);
mapView.setBuiltInZoomControls(true);
mapController = mapView.getController();
mapController.setZoom(16);
}
@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.pin_normal);
canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 24, null);
return true;
}