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因此，我正在開發一個社交活動應用程序，用戶可以發佈活動並讓人們在地圖或列表中看到這些活動。我目前正在努力對我的數據庫中的位置地址進行地理編碼，並將其轉換爲經緯度座標。我已經查看了幾十次代碼，並得到相同的錯誤。 「locationName == null」我得出的唯一結論是，我實際上並沒有從數據庫中提取任何數據，而是向給我這個錯誤的geocoder發送了null值。我正在使用Android Studio和Google Firestore作爲我的數據庫。希望有一些新鮮的眼睛可以讓我對這個問題有所瞭解。如果您需要查看其他相關代碼片段，請告知我們。Geocoder，locationName == null
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;
}
}
錯誤日誌
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(:[email protected]:20)
at com.google.android.gms.maps.internal.bf.a(:[email protected]:5)
at com.google.maps.api.android.lib6.impl.bc.run(:[email protected]: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)
編輯：
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);
}
});
因此，我將數據保存爲數據庫中的對象，並根據上述代碼從數據庫中提取數據。我將地址元素存儲在一個地址變量中，並讓geolocate方法將該代碼轉換爲經緯度座標。
沒有人可以找到經緯度爲空地址。 –
@HareshChhelana我知道，但我想知道爲什麼我試圖拉的地址爲空 –
可能重複[錯誤java.lang.IllegalArgumentException：提供程序== null]（https://stackoverflow.com/questions/12524443/error-on-java-lang-illegalargumentexception-provider-null） –