Geocoder, locationName == null

Question

Also arbeite ich an einer sozialen Ereignis-App, wo Benutzer Ereignisse veröffentlichen können und die Leute diese Ereignisse auf einer Karte oder Liste sehen können. Ich arbeite gerade an dem Versuch, die Standortadresse, die ich in meiner Datenbank habe, zu geocodieren und sie in Lat und Long Coords umzuwandeln. Ich habe Dutzende Male den Code überprüft und den gleichen Fehler erhalten. "locationName == null" Die einzige Schlussfolgerung, zu der ich gekommen bin, ist, dass ich keine Daten aus der Datenbank abrufe und Null-Vale an den Geocoder sende, was mir diesen Fehler gibt. Ich verwende Android Studio mit Google Firestore als meine Datenbank. Hoffentlich können einige frische Augen mir einen Einblick in dieses Thema geben. Lassen Sie mich wissen, wenn Sie andere relevante Code-Schnipsel sehen müssen.

MainActivity.java

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback, GoogleMap.OnMyLocationButtonClickListener, ActivityCompat.OnRequestPermissionsResultCallback { 

private static final String TAG = MainActivity.class.getSimpleName(); 
private ImageButton notifyButton; 
private ImageButton messagesButton; 
private ImageButton exploreButton; 
private ImageButton profileButton; 

private double lat; 
private double lng; 
private String address; 
private String city; 
private String state; 
private int zipcode; 

private LatLng geoCoord; 

/** 
* Request code for location permission request. 
* 
* @see #onRequestPermissionsResult(int, String[], int[]) 
*/ 
private static final int LOCATION_PERMISSION_REQUEST_CODE = 1; 

/** 
* Flag indicating whether a requested permission has been denied after returning in 
* {@link #onRequestPermissionsResult(int, String[], int[])}. 
*/ 
private boolean mPermissionDenied = false; 

private GoogleMap mMap; 
private MarkerOptions options = new MarkerOptions(); 

private FirebaseFirestore db = FirebaseFirestore.getInstance(); 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    setContentView(R.layout.activity_main); 

    notifyButton = (ImageButton) findViewById(R.id.notifyButton); 
    notifyButton.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent main = new Intent(MainActivity.this, NotifyActivity.class); 
      startActivity(main); 
     } 
    }); 

    messagesButton = (ImageButton) findViewById(R.id.messagesButton); 
    messagesButton.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent main = new Intent(MainActivity.this, MessengerActivity.class); 
      startActivity(main); 
     } 
    }); 

    exploreButton = (ImageButton) findViewById(R.id.exploreButton); 
    exploreButton.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent main = new Intent(MainActivity.this, ExploreActivity.class); 
      startActivity(main); 
     } 
    }); 

    profileButton = (ImageButton) findViewById(R.id.profileButton); 
    profileButton.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent main = new Intent(MainActivity.this, ProfileActivity.class); 
      startActivity(main); 
     } 
    }); 



    // Obtain the SupportMapFragment and get notified when the map is ready to be used. 
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() 
      .findFragmentById(map); 
    mapFragment.getMapAsync(this); 


} 




/** 
* Manipulates the map once available. 
* This callback is triggered when the map is ready to be used. 
* This is where we can add markers or lines, add listeners or move the camera. In this case, 
* we just add a marker near Sydney, Australia. 
* If Google Play services is not installed on the device, the user will be prompted to install 
* it inside the SupportMapFragment. This method will only be triggered once the user has 
* installed Google Play services and returned to the app. 
*/ 
@Override 
public void onMapReady(GoogleMap googleMap) { 

    mMap = googleMap; 
    mMap.setOnMyLocationButtonClickListener(this); 
    enableMyLocation(); 


    try { 
     // Customise the styling of the base map using a JSON object defined 
     // in a raw resource file. 
     boolean success = googleMap.setMapStyle(
       MapStyleOptions.loadRawResourceStyle(
         this, R.raw.style_json)); 

     if (!success) { 
      Log.e(TAG, "Style parsing failed."); 
     } 
    } catch (Resources.NotFoundException e) { 
     Log.e(TAG, "Can't find style. Error: ", e); 
    } 
    // Position the map's camera near Sydney, Australia. 

    googleMap.moveCamera(CameraUpdateFactory.newLatLng(new LatLng(-34, 151))); 
    googleMap.addMarker(new MarkerOptions().position(geoLocate())); 
} 

private void enableMyLocation() { 
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) 
      != PackageManager.PERMISSION_GRANTED) { 
     // Permission to access the location is missing. 
     PermissionUtils.requestPermission(this, LOCATION_PERMISSION_REQUEST_CODE, 
       Manifest.permission.ACCESS_FINE_LOCATION, true); 
    } else if (mMap != null) { 
     // Access to the location has been granted to the app. 
     mMap.setMyLocationEnabled(true); 
    } 
} 

@Override 
public boolean onMyLocationButtonClick() { 
    Toast.makeText(this, "Current Location", Toast.LENGTH_SHORT).show(); 
    // Return false so that we don't consume the event and the default behavior still occurs 
    // (the camera animates to the user's current position). 
    return false; 
} 


@Override 
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, 
             @NonNull int[] grantResults) { 
    if (requestCode != LOCATION_PERMISSION_REQUEST_CODE) { 
     return; 
    } 

    if (PermissionUtils.isPermissionGranted(permissions, grantResults, 
      Manifest.permission.ACCESS_FINE_LOCATION)) { 
     // Enable the my location layer if the permission has been granted. 
     enableMyLocation(); 
    } else { 
     // Display the missing permission error dialog when the fragments resume. 
     mPermissionDenied = true; 
    } 
} 

@Override 
protected void onResumeFragments() { 
    super.onResumeFragments(); 
    if (mPermissionDenied) { 
     // Permission was not granted, display error dialog. 
     showMissingPermissionError(); 
     mPermissionDenied = false; 
    } 
} 

/** 
* Displays a dialog with error message explaining that the location permission is missing. 
*/ 
private void showMissingPermissionError() { 
    PermissionUtils.PermissionDeniedDialog 
      .newInstance(true).show(getSupportFragmentManager(), "dialog"); 
} 

public LatLng geoLocate() { 
    Geocoder gc = new Geocoder(this); 
    List <Address> list; 
    try{ 
     list = gc.getFromLocationName(getFullAddress(), 1); 
    } 
    catch (IOException e) { 

     return null; 
    } 
    Address add = list.get(0); 
    String locality = add.getLocality(); 
    Toast.makeText(this, locality, Toast.LENGTH_LONG).show(); 

    return new LatLng(add.getLatitude(), add.getLongitude()); 

} 

public String getFullAddress() { 
    DocumentReference docRef = db.collection("events").document("House Party"); 
    docRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() { 
     @Override 
     public void onSuccess(DocumentSnapshot documentSnapshot) { 
      Event event = documentSnapshot.toObject(Event.class); 
      address = event.getAddress() + ", " + event.getCity() + ", " + event.getState() + " " + event.getZipcode(); 
     } 
    }); 
    return address; 
} 

}

Error Log

FATAL EXCEPTION: main 
                    Process: com.example.android.gathr, PID: 8599 
                    java.lang.IllegalArgumentException: locationName == null 
                     at android.location.Geocoder.getFromLocationName(Geocoder.java:171) 
                     at com.example.android.gathr.MainActivity$override.geoLocate(MainActivity.java:232) 
                     at com.example.android.gathr.MainActivity$override.access$dispatch(MainActivity.java) 
                     at com.example.android.gathr.MainActivity.geoLocate(MainActivity.java:0) 
                     at com.example.android.gathr.MainActivity$override.onMapReady(MainActivity.java:169) 
                     at com.example.android.gathr.MainActivity$override.access$dispatch(MainActivity.java) 
                     at com.example.android.gathr.MainActivity.onMapReady(MainActivity.java:0) 
                     at com.google.android.gms.maps.zzak.zza(Unknown Source) 
                     at com.google.android.gms.maps.internal.zzaq.onTransact(Unknown Source) 
                     at android.os.Binder.transact(Binder.java:507) 
                     at gl.b(:com.google.android.gms.DynamiteModulesB@11518448:20) 
                     at com.google.android.gms.maps.internal.bf.a(:com.google.android.gms.DynamiteModulesB@11518448:5) 
                     at com.google.maps.api.android.lib6.impl.bc.run(:com.google.android.gms.DynamiteModulesB@11518448:5) 
                     at android.os.Handler.handleCallback(Handler.java:751) 
                     at android.os.Handler.dispatchMessage(Handler.java:95) 
                     at android.os.Looper.loop(Looper.java:154) 
                     at android.app.ActivityThread.main(ActivityThread.java:6642) 
                     at java.lang.reflect.Method.invoke(Native Method) 
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) 
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) 

EDIT:

DocumentReference docRef = db.collection("cities").document("BJ"); 
docRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() 
{ 
    @Override 
    public void onSuccess(DocumentSnapshot documentSnapshot) { 
    City city = documentSnapshot.toObject(City.class); 
    } 
    }); 

Also habe ich die Daten als ein Objekt in meiner Datenbank gespeichert und zog aus der Datenbank basierend auf dem obigen Code. Ich zog die Adresselemente, die sie gespeichert hatten, in eine Adressvariable und ließ die Geolocate-Methode diesen Code in eine Lat- und Long-Koordinate umwandeln.

Answer 1

In getFullAddress() rufen Sie, was ich davon ausgehen, ist ein asynchroner Vorgang (docRef.get()) address zu setzen, aber sie zurückkehren address sofort ohne für den Hörer warten Sie ausführen hinzugefügt.

Um dies zu umgehen, könnten Sie die Geocodierung in den onSuccess Callback verschieben, was den netten Nebeneffekt haben würde, nur den Geocode durchzuführen, wenn die Dokumentensuche funktioniert.