为什么当我尝试上传到 Firebase 数据库时，此活动会崩溃?

Question

我正在构建一个应用程序来跟踪设备从另一台设备的位置。现在，我面临的问题是当我尝试将纬度和经度上传到Firebase数据库时它崩溃了。但是，如果我使用 Toast 仅显示纬度和经度，它不会崩溃。

驱动程序地图活动.java

public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
GoogleApiClient mGoogleApiClient;
Location mLastLocation;
Marker mCurrLocationMarker;
LocationRequest mLocationRequest;
private GoogleMap mMap;
private FirebaseAuth mAuth;
private FirebaseUser mUser;
private FirebaseDatabase mFirebaseDatabase;
private DatabaseReference mDatabaseReference;
String userid;
double lat;
double lon;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_driver_maps);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
SupportMapFragment mapFragment = (SupportMapFragment)
getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);


}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
} else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
mLocationRequest, this);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onLocationChanged(final Location location) {
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
LocationManager locationManager = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);
String provider = locationManager.getBestProvider(new Criteria(), true);
if (ActivityCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
return;
}
Location locations = locationManager.getLastKnownLocation(provider);
List<String> providerList = locationManager.getAllProviders();
if (null != locations && null != providerList && providerList.size() > 0) {
double longitude = locations.getLongitude();
double latitude = locations.getLatitude();
Geocoder geocoder = new Geocoder(getApplicationContext(),
Locale.getDefault());
try {
List<Address> listAddresses = geocoder.getFromLocation(latitude, longitude, 1);
if (null != listAddresses && listAddresses.size() > 0) {
String state = listAddresses.get(0).getAdminArea();
String country = listAddresses.get(0).getCountryName();
String subLocality = listAddresses.get(0).getSubLocality();
}
} catch (IOException e) {
e.printStackTrace();
}
}

mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(17));
lat = location.getLatitude();
lon = location.getLongitude();
mUser = FirebaseAuth.getInstance().getCurrentUser();
assert mUser != null;
userid = mUser.getUid();
mDatabaseReference.child("users").child(userid).child("Latitude").setValue(lat);
mDatabaseReference.child("users").child(userid).child("Longitude").setValue(lon);
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient,
this);
}

}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public boolean checkLocationPermission() {
if (ContextCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
android.Manifest.permission.ACCESS_FINE_LOCATION)) {
ActivityCompat.requestPermissions(this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
ActivityCompat.requestPermissions(this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (ContextCompat.checkSelfPermission(this,
android.Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
Toast.makeText(this, "permission denied",
Toast.LENGTH_LONG).show();
}
return;
}
}
}
}

问题出在这一部分

lat = location.getLatitude();
lon = location.getLongitude();
mUser = FirebaseAuth.getInstance().getCurrentUser();
assert mUser != null;
userid = mUser.getUid();
mDatabaseReference.child("users").child(userid).child("Latitude").setValue(lat);
mDatabaseReference.child("users").child(userid).child("Longitude").setValue(lon);

我甚至尝试使用 java 类上传值，然后将值传递给该类。

有人可以帮忙吗？！

日志猫

E/UncaughtException(18714):     at com.oxford.gpstracker.DriverMapsActivity.onLocationChanged(DriverMapsActivity.java:169)
E/UncaughtException(18714):     at com.google.android.gms.internal.zzcdi.zzq(Unknown Source)
E/UncaughtException(18714):     at com.google.android.gms.internal.zzbdw.zzb(Unknown Source)
E/UncaughtException(18714):     at com.google.android.gms.internal.zzbdx.handleMessage(Unknown Source)
E/UncaughtException(18714):     at android.os.Handler.dispatchMessage(Handler.java:102)
E/UncaughtException(18714):     at android.os.Looper.loop(Looper.java:148)
E/UncaughtException(18714):     at android.app.ActivityThread.main(ActivityThread.java:5469)

Answer 1

mDatabaseReference必须在使用前初始化。 您可以在使用前立即执行此操作，如下所示或onCreate().

lat = location.getLatitude();
lon = location.getLongitude();
mUser = FirebaseAuth.getInstance().getCurrentUser();
assert mUser != null;
userid = mUser.getUid();
mDatabaseReference = FirebaseDatabase.getInstance().getReference(); // ADDED
mDatabaseReference.child("users").child(userid).child("Latitude").setValue(lat);
mDatabaseReference.child("users").child(userid).child("Longitude").setValue(lon);