在Google地图上查找位置

Question

我正在尝试在Google地图上找到我的位置。我的代码在这里。我在我的电话中运行了我的应用程序，但很不幸停止了。任何想法可能是什么问题？谢谢。

public class MainActivity extends Activity implements LocationListener { 

    private LatLng loc ; 
    private LocationManager locationManager; 
    private String provider; 

    @SuppressLint("NewApi") 
    @Override 
    protected void onCreate(Bundle savedInstanceState){ 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 

     Criteria criteria = new Criteria(); 
     provider = locationManager.getBestProvider(criteria, false); 
     Location location = locationManager.getLastKnownLocation(provider); 

     if (location != null) { 
     onLocationChanged(location); 
     } 

     GoogleMap map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap(); 
     map.addMarker(new MarkerOptions().position(loc).title("Istanbul")); 
     map.moveCamera(CameraUpdateFactory.newLatLngZoom(loc, 15)); 
     map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null); 
    } 

    @Override 
    public void onLocationChanged(Location location) { 
     double lat = (double) (location.getLatitude()); 
     double lng = (double) (location.getLongitude()); 
     loc = new LatLng(lat,lng); 
    } 

    @Override 
    public void onProviderDisabled(String provider) { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void onProviderEnabled(String provider) { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void onStatusChanged(String provider, int status, Bundle extras) { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    protected void onResume() { 
     super.onResume(); 
     locationManager.requestLocationUpdates(provider, 400, 1, this); 
    } 

    @Override 
    protected void onPause() { 

     super.onPause(); 
     locationManager.removeUpdates(this); 
    } 
    } 

Answer 1

public class MainActivity extends FragmentActivity implements LocationListener { 

GoogleMap googleMap; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    // Getting Google Play availability status 
    int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext()); 

    // Showing status 
    if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available 

     int requestCode = 10; 
     Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode); 
     dialog.show(); 

    }else { // Google Play Services are available 

     // Getting reference to the SupportMapFragment of activity_main.xml 
     SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map); 

     // Getting GoogleMap object from the fragment 
     googleMap = fm.getMap(); 

     // Enabling MyLocation Layer of Google Map 
     googleMap.setMyLocationEnabled(true); 

     // Getting LocationManager object from System Service LOCATION_SERVICE 
     LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE); 

     // Creating a criteria object to retrieve provider 
     Criteria criteria = new Criteria(); 

     // Getting the name of the best provider 
     String provider = locationManager.getBestProvider(criteria, true); 

     // Getting Current Location 
     Location location = locationManager.getLastKnownLocation(provider); 

     if(location!=null){ 
      onLocationChanged(location); 
     } 
     locationManager.requestLocationUpdates(provider, 20000, 0, this); 
    } 
} 
@Override 
public void onLocationChanged(Location location) { 

    TextView tvLocation = (TextView) findViewById(R.id.tv_location); 

    // Getting latitude of the current location 
    double latitude = location.getLatitude(); 

    // Getting longitude of the current location 
    double longitude = location.getLongitude(); 

    // Creating a LatLng object for the current location 
    LatLng latLng = new LatLng(latitude, longitude); 

    // Showing the current location in Google Map 
    googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng)); 

    // Zoom in the Google Map 
    googleMap.animateCamera(CameraUpdateFactory.zoomTo(15)); 

    // Setting latitude and longitude in the TextView tv_location 
    tvLocation.setText("Latitude:" + latitude + ", Longitude:"+ longitude); 

} 

@Override 
public void onProviderDisabled(String provider) { 
    // TODO Auto-generated method stub 
} 

@Override 
public void onProviderEnabled(String provider) { 
    // TODO Auto-generated method stub 
} 

@Override 
public void onStatusChanged(String provider, int status, Bundle extras) { 
    // TODO Auto-generated method stub 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.activity_main, menu); 
    return true; 
} 
} 

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Answer 2

// try this 
**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:padding="5dp" 
    android:orientation="vertical"> 

    <fragment 
     android:id="@+id/maps" 
     android:name="pl.mg6.android.maps.extensions.SupportMapFragment" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" /> 

</LinearLayout> 

public class MyActivity extends FragmentActivity { 


    public static LocationManager mlocManager; 
    public static LocationListner mListner; 
    GoogleMap map; 

    @Override 
    protected void onCreate(Bundle savedInstanceState){ 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

     map = getMapView(); 
     map.setMyLocationEnabled(true); 

     try { 
      mlocManager = (LocationManager) getSystemService(Activity.LOCATION_SERVICE); 
      mListner = new LocationListner(); 
      runOnUiThread(new Runnable() { 

       @Override 
       public void run() { 
        try { 
         try { 
          mlocManager.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER, 0, 0, mListner); 
         } catch (Throwable e) { 
          e.printStackTrace(); 
         } 

         mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mListner); 
        } catch (Throwable e) { 
         e.printStackTrace(); 
        } 
        try { 
         mlocManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, mListner); 
        } catch (Throwable e) { 
         e.printStackTrace(); 
        } 

       } 
      }); 
     } catch (Throwable e) { 
      e.printStackTrace(); 
     } 

    } 

    public GoogleMap getMapView() { 
     FragmentManager fm = getSupportFragmentManager(); 
     SupportMapFragment f = (SupportMapFragment) fm.findFragmentById(R.id.maps); 

     // Getting GoogleMap object from the fragment 
     return f.getExtendedMap(); 
    } 

    public void setMapMarker(LatLng loc){ 
     map.addMarker(new MarkerOptions().position(loc).title("Istanbul")); 
     map.moveCamera(CameraUpdateFactory.newLatLngZoom(loc, 15)); 
     map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null); 
    } 


    class LocationListner implements LocationListener { 

     @Override 
     public void onLocationChanged(Location location) { 
      setMapMarker(new LatLng(location.getLatitude(),location.getLongitude())); 
     } 

     @Override 
     public void onProviderDisabled(String provider) { 
     } 

     @Override 
     public void onProviderEnabled(String provider) { 
     } 

     @Override 
     public void onStatusChanged(String provider, int status, Bundle extras) { 
     } 

    } 
} 

Answer 3

在此行中：

map.addMarker(new MarkerOptions().position(loc).title("Istanbul")); 

禄是空

而且，你不应该叫onLocationChanged（）直接，这是一个回电话。整个过程都是事件驱动的，即当GPS或网络为您提供该方法触发的位置时。