如何使用谷歌地图Api获得最精确的位置

Question

我正在尝试使用谷歌地图API获取用户的当前位置，但即使在打开GPS后，我也无法最准确地获取当前位置，尽管我没有收到任何错误。首先，我检查权限，然后我检查是否启用了GPS，然后在当前位置显示标记

我的代码

public class MapsActivity extends AppCompatActivity implements OnMapReadyCallback {
public static final int DEFAULT_ZOOM = 15;
public static final int PERMISSION_REQUEST_CODE = 9001;
private static final int PLAY_SERVICES_ERROR_CODE = 9002;
public static final String TAG = "MyTag";
private boolean mLocationPermissionGranted;
private FusedLocationProviderClient mLocationClient;
Toolbar toolbar;
String LatitudeBack;
String LongitudeBack;

Double LATITUDE,LONGITUDE;
private double Delhi_LAT = 28.630597;
private double Delhi_LONG= 77.218978;

private GoogleMap mGoogleMap;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
toolbar = findViewById(R.id.myToolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});

isServicesOk();
mLocationClient = new FusedLocationProviderClient(this);
SupportMapFragment supportMapFragment= (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map_fragment);
assert supportMapFragment != null;
supportMapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mGoogleMap = googleMap;
}
private void initGoogleMap() {
if(isServicesOk()){
if (isGPSEnabled()) {
if (checkLocationPermission()) {
SupportMapFragment supportMapFragment = SupportMapFragment.newInstance();
getCurrentLocation();
} else {
requestLocationPermission();
}
}
}

}
private void requestLocationPermission() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, PERMISSION_REQUEST_CODE);
}
}
}
private void gotoLocation(double lat,double lng){
LatLng latLng=new LatLng(lat,lng);
CameraUpdate cameraUpdate= CameraUpdateFactory.newLatLngZoom(latLng,DEFAULT_ZOOM);
mGoogleMap.moveCamera(cameraUpdate);
mGoogleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
}
private boolean checkLocationPermission() {
return ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED;
}
private boolean isServicesOk() {
GoogleApiAvailability googleApi = GoogleApiAvailability.getInstance();
int result= googleApi.isGooglePlayServicesAvailable(this);
if(result == ConnectionResult.SUCCESS){
return true;
}else if(googleApi.isUserResolvableError(result)){
Dialog dialog=googleApi.getErrorDialog(this,result,PLAY_SERVICES_ERROR_CODE, task->
Toast.makeText(this, "Dialog is cancelled by User", Toast.LENGTH_SHORT).show());
dialog.show();
}else{
Toast.makeText(this, "Play services are required by this application", Toast.LENGTH_SHORT).show();
}
return false;
}
private void showMarker(double lat, double lng) {
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(new LatLng(lat, lng));
mGoogleMap.addMarker(markerOptions);
}
@Override
public void onBackPressed() {
super.onBackPressed();
Intent intent =new Intent(MapsActivity.this,Upload_New_Product.class);
startActivity(intent);
}
private void getCurrentLocation() {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
{
// TODO: Consider calling
//    ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
//   public void onRequestPermissionsResult(int requestCode, String[] permissions,
//                                          int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
mLocationClient.getLastLocation().addOnCompleteListener(new OnCompleteListener<Location>() {
@Override
public void onComplete(@NonNull Task<Location> task) {
if (task.isSuccessful())
{
Location location = task.getResult();
assert location != null;
Log.d(TAG,"Map 2 , "+String.valueOf(location.getLatitude())+ location.getLongitude());
LATITUDE =location.getLatitude();
LONGITUDE =location.getLongitude();
gotoLocation(LATITUDE,LONGITUDE);
showMarker(LATITUDE,LONGITUDE);
//  LocationEditText.setText(MyLat+","+MyLong);
// geoCoder(location.getLatitude(),location.getLongitude());
}
else
{
Log.d(TAG, "getCurrentLocation: Error: " + task.getException().getMessage());
Toast.makeText(MapsActivity.this, "Can't get Location", Toast.LENGTH_SHORT).show();
}

}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_map, menu);

return super.onCreateOptionsMenu(menu);

}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
if (item.getItemId() == R.id.CurrentLocation) {
initGoogleMap();

}
return super.onOptionsItemSelected(item);

}
private boolean isGPSEnabled() {
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
boolean providerEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
if (providerEnabled) {
return true;
} else {
AlertDialog alertDialog = new AlertDialog.Builder(this)
.setTitle("GPS Permissions")
.setMessage("GPS is required for accessing the Shop location. Please enable GPS.")
.setPositiveButton("OK", ((dialogInterface, i) -> {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivityForResult(intent, GPS_REQUEST_CODE);
}))
.setCancelable(false)
.show();
}
return false;
}
}

Answer 1

getLastLocation((不会激活位置更新，因此可能不会返回设备的最新位置，您必须调用requestLocationUpdates((并设置回调以接收新的位置更新。