可能重复：
positing user current location and show it in Google maps
我正在开发具有Map Activity的应用程序。这张地图应该：
这是我的代码
public class MapStackActivity extends MapActivity {
String provider;
public double latitude, longitude = 0;
CurrentPositionTask getCurrentLocation;
Location currentLocation;
LocationListener locationListener;
LocationManager locationManager;
private long time=0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
setCriteria();
currentLocation = MapStackActivity.this.locationManager.getLastKnownLocation(provider);
if (currentLocation == null) {
currentLocation = new Location(provider);
}
time = currentLocation.getTime();
if (latitude == 0 && longitude == 0) {
latitude = currentLocation.getLatitude();
longitude = currentLocation.getLongitude();
}
Toast.makeText(MapStackActivity.this, String.valueOf(time), Toast.LENGTH_LONG).show();
if (time >= 100000) {
latitude = 0;
longitude = 0;
}
} catch (NullPointerException e) {
// TODO: handle exception
System.out.println("Null");
e.printStackTrace();
}
catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
runAsyncTask();
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
locationManager.removeUpdates(locationListener);
}
public void setCriteria() {
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_MEDIUM);
provider = locationManager.getBestProvider(criteria, true);
Toast.makeText(getApplicationContext(), "Provider - " + provider, Toast.LENGTH_SHORT).show();
if (provider == null) {
provider = LocationManager.GPS_PROVIDER;
}
}
public void runAsyncTask() {
// TODO Auto-generated method stub
if (getCurrentLocation == null) {
getCurrentLocation = new CurrentPositionTask();
}
if (getCurrentLocation != null) {
getCurrentLocation.execute("Searching for Location");
}
}
public boolean checkConnection()
{
//ARE WE CONNECTED TO THE NET
ConnectivityManager conMgr = (ConnectivityManager) getSystemService (MapStackActivity.CONNECTIVITY_SERVICE);
if (conMgr.getActiveNetworkInfo() != null && conMgr.getActiveNetworkInfo().isAvailable()&& conMgr.getActiveNetworkInfo().isConnected()) {
return true;
} else {
return false;
}
}
private class CurrentPositionTask extends AsyncTask<String, Void, Void>
{
private ProgressDialog Dialog = new ProgressDialog(MapStackActivity.this);
private boolean flag = true;
public CurrentPositionTask() {
locationListener = new MyLocationListener();
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
try {
if (checkConnection()) {
Dialog.setTitle("Loading");
Dialog.setMessage("Searching for Location");
Dialog.show();
locationManager.requestLocationUpdates(provider, 0, 0, locationListener);
}
else {
Toast.makeText(getApplicationContext(), "Internet is Not Available", Toast.LENGTH_LONG).show();
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
Toast.makeText(MapStackActivity.this, "Location Floats:- " + latitude + "," + longitude, Toast.LENGTH_LONG).show();
super.onPostExecute(result);
if (Dialog != null && Dialog.isShowing()) {
Dialog.dismiss();
time=0;
Intent homeIntent = new Intent(MapStackActivity.this.getApplicationContext(), HomeMenuActivity.class);
homeIntent.putExtra("lat", latitude);
homeIntent.putExtra("lng", longitude);
startActivity(homeIntent);
}
locationManager.removeUpdates(locationListener);
}
@Override
protected Void doInBackground(String... params) {
// TODO Auto-generated method stub
return null;
}
}
class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
Toast.makeText( getApplicationContext(),"Gps Disabled",Toast.LENGTH_SHORT).show();
}
@Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
Toast.makeText( getApplicationContext(),"Gps Enabled",Toast.LENGTH_SHORT).show();
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
} }
第二个活动是：
public class HomeMenuActivity extends Activity{
public static Context context;
GeoPoint geoPoint;
MapView mapview;
MapController mapControll;
Drawable userPic;
public double latitude=0;
public double longitude = 0;
MyItemizedOverlay userPicOverlay;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
context = getApplicationContext(); // it will be used in Itemized Overlay
latitude = getIntent().getDoubleExtra("lat", 0);//get the lat & lng
longitude = getIntent().getDoubleExtra("lng", 0);
}
public void showMap() {
// TODO Auto-generated method stub
try {
geoPoint = new GeoPoint((int)(latitude * 1E6),(int)(longitude * 1E6));
mapview = (MapView)findViewById(R.id.mapview);
mapControll= mapview.getController();
mapview.setBuiltInZoomControls(true);
mapview.setStreetView(true);
mapview.setTraffic(true);
mapControll.setZoom(16);
mapControll.animateTo(geoPoint);
userPic = this.getResources().getDrawable(R.drawable.ic_launcher);
userPicOverlay = new MyItemizedOverlay(userPic);
OverlayItem overlayItem = new OverlayItem(geoPoint, "", null);
userPicOverlay.addOverlay(overlayItem);
mapview.getOverlays().add(userPicOverlay);
//Added symbols will be displayed when map is redrawn so force redraw now
mapview.postInvalidate();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
public class MyItemizedOverlay extends ItemizedOverlay<OverlayItem> {
private ArrayList<OverlayItem> myOverlays ;
public MyItemizedOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
myOverlays = new ArrayList<OverlayItem>();
populate();
}
public void addOverlay(OverlayItem overlay){
myOverlays.add(overlay);
populate();
}
@Override
protected OverlayItem createItem(int i) {
return myOverlays.get(i);
}
// Removes overlay item i
public void removeItem(int i){
myOverlays.remove(i);
populate();
}
// Returns present number of items in list
@Override
public int size() {
return myOverlays.size();
}
public void addOverlayItem(OverlayItem overlayItem) {
myOverlays.add(overlayItem);
populate();
}
public void addOverlayItem(int lat, int lon, String title) {
try {
GeoPoint point = new GeoPoint(lat, lon);
OverlayItem overlayItem = new OverlayItem(point, title, null);
addOverlayItem(overlayItem);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
protected boolean onTap(int index) {
// TODO Auto-generated method stub
String title = myOverlays.get(index).getTitle();
Toast.makeText(HomeMenuActivity.context, title, Toast.LENGTH_LONG).show();
return super.onTap(index);
}
}}
它不起作用，只是给我Toast“provider -Gps”然后“0”然后“Location float 0.0,0.0”。有什么问题，我该如何解决？