Question

我在android中使用FusedLocationProviderClient类来获取用户的最后位置。一切都很好，我可以获取经度和纬度，但是task.getResult().getBearing()返回0.0，而task.getResult().hasBearing()返回false。如何获取用户的方位信息？

我在AndroidManifest文件中和运行时都获得了ACCESS_FINE_LOCATION和ACCESS_COARSE_LOCATION的权限。

这是与我使用的用户位置有关的代码：

@SuppressLint("MissingPermission")
private void getLastLocation() {
    fusedLocationClient
            .getLastLocation()
            .addOnCompleteListener(this, new OnCompleteListener<Location>() {
                @Override
                public void onComplete(@NonNull Task<Location> task) {
                    if (task.isSuccessful() && task.getResult() != null) {
                        onLocationChange(task.getResult());
                        Log.i(TAG, "lat " + task.getResult().getLatitude() + " lng " + task.getResult().getLongitude());
                        Log.i(TAG, "bearing? " + task.getResult().hasBearing());
                    } else {
                        Toast.makeText(MainActivity.this, "Location Not Found!", Toast.LENGTH_SHORT).show();
                    }
                }
            });

}

private void onLocationChange(Location location) {
    //do something
}

Answer 1

根据documentation

如果该位置没有方位，则返回0.0。

Answer 2

我使用加速度计和磁场传感器解决了我的问题。 This是我用来学习手机的Compass类：

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;

public class Compass implements SensorEventListener {
    private static final String TAG = "Compass";

    public interface CompassListener {
        void onNewAzimuth(float azimuth);
    }

    private CompassListener listener;

    private SensorManager sensorManager;
    private Sensor gsensor;
    private Sensor msensor;

    private float[] mGravity = new float[3];
    private float[] mGeomagnetic = new float[3];
    private float[] R = new float[9];
    private float[] I = new float[9];

    private float azimuth;
    private float azimuthFix;

    public Compass(Context context) {
        sensorManager = (SensorManager) context
                .getSystemService(Context.SENSOR_SERVICE);
        gsensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        msensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
    }

    public void start() {
        sensorManager.registerListener(this, gsensor,
                SensorManager.SENSOR_DELAY_GAME);
        sensorManager.registerListener(this, msensor,
                SensorManager.SENSOR_DELAY_GAME);
    }

    public void stop() {
        sensorManager.unregisterListener(this);
    }

    public void setAzimuthFix(float fix) {
        azimuthFix = fix;
    }

    public void resetAzimuthFix() {
        setAzimuthFix(0);
    }

    public void setListener(CompassListener l) {
        listener = l;
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        final float alpha = 0.97f;

        synchronized (this) {
            if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {

                mGravity[0] = alpha * mGravity[0] + (1 - alpha)
                        * event.values[0];
                mGravity[1] = alpha * mGravity[1] + (1 - alpha)
                        * event.values[1];
                mGravity[2] = alpha * mGravity[2] + (1 - alpha)
                        * event.values[2];

                // mGravity = event.values;

                // Log.e(TAG, Float.toString(mGravity[0]));
            }

            if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {
                // mGeomagnetic = event.values;

                mGeomagnetic[0] = alpha * mGeomagnetic[0] + (1 - alpha)
                        * event.values[0];
                mGeomagnetic[1] = alpha * mGeomagnetic[1] + (1 - alpha)
                        * event.values[1];
                mGeomagnetic[2] = alpha * mGeomagnetic[2] + (1 - alpha)
                        * event.values[2];
                // Log.e(TAG, Float.toString(event.values[0]));

            }

            boolean success = SensorManager.getRotationMatrix(R, I, mGravity,
                    mGeomagnetic);
            if (success) {
                float orientation[] = new float[3];
                SensorManager.getOrientation(R, orientation);
                // Log.d(TAG, "azimuth (rad): " + azimuth);
                azimuth = (float) Math.toDegrees(orientation[0]); // orientation
                azimuth = (azimuth + azimuthFix + 360) % 360;
                // Log.d(TAG, "azimuth (deg): " + azimuth);
                if (listener != null) {
                    listener.onNewAzimuth(azimuth);
                }
            }
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
}

我通过将352添加到此类的onNewAzimuth方法所接收的方位上来校准该值，并将其用于我的代码中：

    Compass compass = new Compass(this);
    Compass.CompassListener cl = new Compass.CompassListener() {

        @Override
        public void onNewAzimuth(float azimuth) {
            // using (360 - (azimuth) + 8) value
        }
    };
    compass.setListener(cl);

FusedLocationProviderClient没有方位数据

2 个答案: