android - Location.distanceBetween 获取不到距离、范围、米，无法识别latlong变量

Question

如果他让圆圈，我试图从用户那里获取范围，但我无法在屏幕上获取范围或距离，它始终显示 0.0，并且不显示 toast 。

public class HomeActivity extends AppCompatActivity implements OnMapReadyCallback {
    /**
     * 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;

    LatLng latLng;
    GoogleMap mMap;
    SupportMapFragment supportMapFragment;
    Marker marker;

    //textview para mostrar el email, nombre, id del usuario conectado actualmente
    TextView textViewEmail;

    Context context;

    double latitudeF, longitudeF;

    TextView locationText;
    TextView tiempoText;
    TextView rangoText;
    TextView longitudeText;
    TextView latitudeText;

    //Float distance;

    Circle circle;

    String dist;

    private static final String TAG = "MyApp";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);

        supportMapFragment = (SupportMapFragment) getSupportFragmentManager
                ().findFragmentById(R.id.mapHomeUbication);
        supportMapFragment.getMapAsync(this);

        context = this;

        // inicializamos el textview
        textViewEmail = (TextView)findViewById(R.id.txt_EmailUsuario);
        locationText = (TextView) findViewById(R.id.location);
        longitudeText = (TextView) findViewById(R.id.longitude);
        latitudeText = (TextView) findViewById(R.id.latitude);
        tiempoText = (TextView) findViewById(R.id.tiempo);
        rangoText = (TextView )findViewById(R.id.rango);

        // cargamos el email desde sharedpreferences
        SharedPreferences sharedPreferences = getSharedPreferences
                (Config.SHARED_PREF_NAME, Context.MODE_PRIVATE);
        String email = sharedPreferences.getString(Config.EMAIL_SHARED_PREF, "No Disponible");

        // mostramos el email actualmente logueado
        textViewEmail.setText("Usuario : " + email);

        onMapReady(mMap);

    }

    // function salir
    private void logout() {
        //Creating an alert dialog to confirm logout
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
        alertDialogBuilder.setMessage("Esta seguro que quiere salir?");
        alertDialogBuilder.setPositiveButton("Sí",
            new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface arg0, int arg1) {

                    //Getting out sharedpreferences
                    SharedPreferences preferences = getSharedPreferences
                            (Config.SHARED_PREF_NAME,Context.MODE_PRIVATE);
                    //Getting editor
                    SharedPreferences.Editor editor = preferences.edit();

                    //Puting the value false for loggedin
                    editor.putBoolean(Config.LOGGEDIN_SHARED_PREF, false);

                    //Putting blank value to email
                    editor.putString(Config.EMAIL_SHARED_PREF, "");

                    //Saving the sharedpreferences
                    editor.commit();

                    //Starting login activity
                    Intent intent = new Intent(HomeActivity.this,
                            LoginActivity.class);
                    startActivity(intent);
                }
            });

        alertDialogBuilder.setNegativeButton("No",
            new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface arg0, int arg1) {

                }
            });

        //Showing the alert dialog
        AlertDialog alertDialog = alertDialogBuilder.create();
        alertDialog.show();

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        //Adding our menu to toolbar
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.log_OutMenu) {
            //calling logout method when the logout button is clicked
            logout();
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onBackPressed() {

        super.onBackPressed();
        finish();

    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        setUpMap();
    }

    /**
     * This is where we can add markers or lines, add listeners or move the camera.
     In this case, we
     * just add a marker near Africa.
     * <p/>
     * This should only be called once.
     */
    private void setUpMap() {
        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) {
            mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
            mMap.getUiSettings().setZoomControlsEnabled(true);
            mMap.setMyLocationEnabled(true);
            mMap.setOnMyLocationChangeListener(myLocationChangeListener());
        }
    }

    private GoogleMap.OnMyLocationChangeListener myLocationChangeListener() {
        return new GoogleMap.OnMyLocationChangeListener() {
            @Override
            public void onMyLocationChange(Location location) {
                LatLng latLngI  = new LatLng(location.getLatitude(),
                        location.getLongitude());
                longitudeF = location.getLongitude();
                latitudeF = location.getLatitude();

                DateFormat format = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
                Date date = new Date(location.getTime());
                String formatted = format.format(date);
                tiempoText.setText(formatted.toString());

                mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng
                        (latitudeF, longitudeF), 13));

                MarkerOptions options = new MarkerOptions();

                // Setting the position of the marker

                options.position(new LatLng(latitudeF, longitudeF));

                latLng = new LatLng(latitudeF, longitudeF);

                drawMarkerWithCircle(latLng);

                // Get back the mutable Circle
                //circle = mMap.addCircle(circleOptions);

                //getDistance(latLngI, latLng);

                float[] distance = new float[2];

                Location.distanceBetween( marker.getPosition().latitude,
                        marker.getPosition().longitude,
                        circle.getCenter().latitude, circle.getCenter
                                ().longitude, distance);

                if (distance[0] > circle.getRadius()) {
                    Toast.makeText(getBaseContext(), "fuera del rango: "
                            + distance[0] + " radio: " + circle.getRadius(), Toast.LENGTH_LONG).show();
                } else if (distance[0] < circle.getRadius()) {
                    Toast.makeText(getBaseContext(), "dentro del rango: "
                            + distance[0] + " radio: " + circle.getRadius() , Toast.LENGTH_LONG).show();
                }

                //mMap.addMarker(new MarkerOptions().position(latLng));
                //mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng,8.0f));
                locationText.setText("estas en [" + longitudeF + " ; " + latitudeF
                        + "] ");
                Log.d(TAG, "onMyLocationChange: 1" + distance);
            }
        };
    }

    private void drawMarkerWithCircle(LatLng position) {
        double radiusInMeters = 300;
        int strokeColor = 0xffff0000; //red outline
        int shadeColor = 0x44ff0000; //opaque red fill

        CircleOptions circleOptions = new CircleOptions().center(position).radius
                (radiusInMeters).fillColor(shadeColor).strokeColor(strokeColor).strokeWidth(8);
        circle = mMap.addCircle(circleOptions);

        MarkerOptions markerOptions = new MarkerOptions().position(position);
        marker = mMap.addMarker(markerOptions);
    }
}

这是 logcat，它只显示一个数组，但如果移动标记，它看起来总是在变化

01-04 04:03:31.766 5838-5864/com.google.android.gms.persistent I/dalvikvm: Could not find method android.location.Location.isFromMockProvider, referenced from method com.google.android.location.util.am.e 01-04 04:03:31.766 5838-5864/com.google.android.gms.persistent W/dalvikvm: VFY: unable to resolve virtual method 995: Landroid/location/Location;.isFromMockProvider ()Z 01-04 04:03:31.766 5838-5864/com.google.android.gms.persistent D/dalvikvm: VFY: replacing opcode 0x6e at 0x0019 01-04 04:03:31.822 9501-9501/com.jhon.co.divi D/MyApp: onMyLocationChange: 1[F@53a75360 01-04 04:03:31.834 5838-5838/com.google.android.gms.persistent I/dalvikvm: Could not find method android.os.Looper.quitSafely, referenced from method com.google.android.gms.fitness.service.b.c.onDestroy 01-04 04:03:31.842 5838-5838/com.google.android.gms.persistent W/dalvikvm: VFY: unable to resolve virtual method 1351: Landroid/os/Looper;.quitSafely ()V 01-04 04:03:31.842 5838-5838/com.google.android.gms.persistent D/dalvikvm: VFY: replacing opcode 0x6e at 0x000f 01-04 04:03:31.854 5838-5838/com.google.android.gms.persistent V/GeofencerHelper: Initializing geofence's system cache. 01-04 04:03:31.862 5838-5858/com.google.android.gms.persistent D/GeofenceStateCache: Recovered 0 geofences. 01-04 04:03:31.886 5838-5838/com.google.android.gms.persistent I/dalvikvm: Could not find method android.os.Process.myUserHandle, referenced from method com.google.android.location.internal.server.o.f 01-04 04:03:31.886 5838-5838/com.google.android.gms.persistent W/dalvikvm: VFY: unable to resolve static method 1464: Landroid/os/Process;.myUserHandle ()Landroid/os/UserHandle; 01-04 04:03:31.886 5838-5838/com.google.android.gms.persistent D/dalvikvm: VFY: replacing opcode 0x71 at 0x00a7

它是这样的:

我不明白为什么它总是返回 0.0 并且不在 Location.distanceBetween 中进行验证。

Answer 1

            postRef.addChildEventListener( new ChildEventListener() {

        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {

            if (!dataSnapshot.exists()) {
               // Toast.makeText(this, "if", Toast.LENGTH_SHORT ).show();

            } else {

                String latitude_Display = dataSnapshot
                        .child( "Pro_file" )
                        .child( "bpro_latitude" )
                        .getValue().toString();

                String longitude_Display = dataSnapshot
                        .child( "Pro_file" )
                        .child( "bpro_longitude" )
                        .getValue().toString();

                //Toast.makeText(this, "else " + latitude_Display + "\n" + longitude_Display, Toast.LENGTH_SHORT ).show();

                String latLng = latitude_Display;
                String latLng1 = longitude_Display;

                double latitude_C = Double.parseDouble(latLng);
                double longitude_C = Double.parseDouble(latLng1);

                LocationManager locationManager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );
                Criteria crit = new Criteria();
                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) {
                    // 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;
                }
                Location location = locationManager.getLastKnownLocation( locationManager.getBestProvider( crit, false ) );
                float[] distance = new float[2];
                CircleOptions circleOptions_b = new CircleOptions();
                circleOptions_b.center(new LatLng(location.getLatitude(), location.getLongitude()));
                circleOptions_b.radius(100000);
                Location.distanceBetween( latitude_C, longitude_C,
                circleOptions_b.getCenter().latitude, circleOptions_b.getCenter().longitude, distance);

                if( distance[0] > circleOptions_b.getRadius()  ){
                    Toast.makeText(this, "the user Outside", Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(this, "the user Inside", Toast.LENGTH_LONG).show();
                    //do something
                    listUsers.add( dataSnapshot
                            .child("Pro_file")
                            .getValue(user.class) );

                    displayUsers(listUsers);
                    find_myAdapter.notifyDataSetChanged();
                }
                }
            }
        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {
            find_myAdapter.notifyDataSetChanged();
        }
        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {
        }

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String s) {
        }
        @Override
        public void onCancelled(DatabaseError databaseError) {
            Toast.makeText(this,"Canceled",Toast.LENGTH_SHORT).show();
            find_myAdapter.notifyDataSetChanged();
        }
    });


}