尝试在onMapReady方法中获取位置时,我的应用程序出现问题。
我试图在不同的变量中获取经度和纬度,但是onMapReady方法仍然将其作为null。
在ToL的getLastLocation方法中,它显示了我的真实位置,但是当我在myLocation之外使用myLocation时,所得坐标为0.0 -0.0
public class MapFragment extends Fragment implements OnMapReadyCallback {
Location myLocation = null;
FusedLocationProviderClient fusedLocation;
private static final int Request_Code = 101;
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
private void getLastLocation() {
if(ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, Request_Code);
}
Task<Location> task = fusedLocation.getLastLocation();
task.addOnSuccessListener(new OnSuccessListener<Location>() {
@Override
public void onSuccess(Location location) {
if(location != null) {
myLocation = location;
Toast.makeText(getContext(), myLocation.getLatitude() + "" + myLocation.getLongitude(), Toast.LENGTH_SHORT).show(); // This correctly shows me my true location
}
}
});
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.map_fragment, container, false);
fusedLocation = LocationServices.getFusedLocationProviderClient(getActivity());
getLastLocation();
SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync( this);
return v;
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode) {
case Request_Code:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
getLastLocation();
}
break;
}
}
@Override
public void onMapReady(GoogleMap googleMap) {
if (googleMap != null) {
LatLng latLng = new LatLng(myLocation.getLatitude(), myLocation.getLongitude());
MarkerOptions marker = new MarkerOptions().position(latLng).title("Estas aquí");
googleMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 6));
googleMap.addMarker(marker);
}
}
}
错误日志:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.mint, PID: 11019
java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference
at com.example.mint.MapFragment.onMapReady(MapFragment.java:81)
at com.google.android.gms.maps.zzak.zza(Unknown Source:2)
at com.google.android.gms.maps.internal.zzaq.dispatchTransaction(Unknown Source:12)
at com.google.android.gms.internal.maps.zzb.onTransact(Unknown Source:12)
at android.os.Binder.transact(Binder.java:667)
at ck.b(:com.google.android.gms.dynamite_mapsdynamite@19629065@19.6.29 (100400-0):14)
at com.google.android.gms.maps.internal.bb.a(:com.google.android.gms.dynamite_mapsdynamite@19629065@19.6.29 (100400-0):4)
at com.google.maps.api.android.lib6.impl.bi.run(:com.google.android.gms.dynamite_mapsdynamite@19629065@19.6.29 (100400-0):2)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at ln.dispatchMessage(:com.google.android.gms.dynamite_mapsdynamite@19629065@19.6.29 (100400-0):5)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6672)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:495)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:860)
I/Process: Sending signal. PID: 11019 SIG: 9
Process 11019 terminated.
答案 0 :(得分:0)
您的代码抛出nullPointerException,因为myLocation仍然为null,因此请尝试使用以下代码
public class MapFragment extends Fragment implements OnMapReadyCallback {
Location myLocation = null;
FusedLocationProviderClient fusedLocation;
private static final int Request_Code = 101;
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
private void getLastLocation() {
if(ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, Request_Code);
}
Task<Location> task = fusedLocation.getLastLocation();
task.addOnSuccessListener(new OnSuccessListener<Location>() {
@Override
public void onSuccess(Location location) {
if(location != null) {
myLocation = location;
//change was made here
SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync( this);
Toast.makeText(getContext(), myLocation.getLatitude() + "" + myLocation.getLongitude(), Toast.LENGTH_SHORT).show(); // This correctly shows me my true location
}
}
});
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.map_fragment, container, false);
fusedLocation = LocationServices.getFusedLocationProviderClient(getActivity());
getLastLocation();
return v;
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode) {
case Request_Code:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
getLastLocation();
}
break;
}
}
@Override
public void onMapReady(GoogleMap googleMap) {
if (googleMap != null) {
LatLng latLng = new LatLng(myLocation.getLatitude(), myLocation.getLongitude());
MarkerOptions marker = new MarkerOptions().position(latLng).title("Estas aquí");
googleMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 6));
googleMap.addMarker(marker);
}
}
}