Android 两点之间的定位轴承+；地球曲率问题

我想实施三件事：

1） 基于位置传感器实现罗盘+获取当前坐标

2） 将方位设置为固定目的地

3） 一旦轴承设置，我想设置一个红色的指南针，将继续指向该固定轴承，无论手机旋转

到目前为止，我已经完成了1+2。至于3-我已经设法指向正确的方向针，但随着手机旋转-针也旋转，失去了正确的方向。我尝试了很多东西，但我就是不能让它工作

还有一个问题：如果bearingTo（）方法计算两个位置之间的度数，它会考虑地球曲率吗？如果不是，这仅适用于近距离。。。希望如此：-）

我将感谢任何帮助

下面是我的代码检查注释以供解释。提前谢谢

    @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

            tvCurrAzim = (TextView) findViewById(R.id.tvaz);
            tvCurrLat = (TextView) findViewById(R.id.tvlat);
            tvCurrLng = (TextView) findViewById(R.id.tvlng);
            tvBearing = (TextView) findViewById(R.id.tvbearing);
            tvIndicator = (TextView) findViewById(R.id.tvindicator);
            ivCompass = (ImageView) findViewById(R.id.imageView1); //compass ImageView
            ivArrow = (ImageView) findViewById(R.id.imageView2); //Red Needle ImageView

            // Get the location manager
            locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

            // Define the criteria how to select the location provider -> use
            // default
            Criteria criteria = new Criteria();
            provider = locationManager.getBestProvider(criteria, true);

            location = locationManager.getLastKnownLocation(provider);

            tvCurrLat.setText(String.valueOf(location.getLatitude()));
            tvCurrLng.setText(String.valueOf(location.getLongitude()));

            from = new Location(location); //creating new Location object
            to = new Location(location); //creating new Location object

    //setting lat,lng to destination Location
            to.setLatitude(newLat);
            to.setLongitude(newLng);

            mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
            mCompass = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);

        }

        // Compass Sensor Methods:

        @Override
        public void onAccuracyChanged(Sensor sensor, int accuracy) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onSensorChanged(SensorEvent event) {
            // setting animation for compass
            azimuth = Math.round(event.values[0]);

            tvCurrAzim.setText(Float.toString(azimuth));

            // get the angle around the z-axis rotated
            // float degree = Math.round(event.values[0]);

            // create a rotation animation (reverse turn degree degrees)
            RotateAnimation ra = new RotateAnimation(currentDegree, -azimuth,
                    Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
                    0.5f);

            // how long the animation will take place
            ra.setDuration(210);

            // set the animation after the end of the reservation status
            ra.setFillAfter(true);

            // Start the animation
            ivCompass.startAnimation(ra);
            currentDegree = -azimuth;

            pointArrow();

        }

        // Location Manager Methods:

        public void setBearing() {
            from.setLatitude(location.getLatitude()); //setting lat,lng to origin Location
            from.setLongitude(location.getLongitude());

            bearing = Math.round(from.bearingTo(to));
            tvBearing.setText(String.valueOf(bearing));
            hasBearing = true;
            ivArrow.setVisibility(View.VISIBLE);

        }


        public void pointArrow() {
            if (hasBearing) { //once bearing is set

                // get the angle around the z-axis rotated
                float degree1 = Math.round(azimuth) - (float) bearing;

                // create a rotation animation (reverse turn degree degrees)
                RotateAnimation ra1 = new RotateAnimation(currentDegree1, -degree1,
                        Animation.RELATIVE_TO_SELF, 0.5f,
                        Animation.RELATIVE_TO_SELF, 0.5f);

                // how long the animation will take place
                ra1.setDuration(210);

                // set the animation after the end of the reservation status
                ra1.setFillAfter(true);

                // Start the animation
                ivArrow.startAnimation(ra1);
                currentDegree1 = -degree1;

//THIS METHOD WORKS TO POINT THE NEEDLE IN CORRECT DIRECTION, BUT AS PHONE ROTATES THE NEEDLE ROTATES TOO.
//I WANT IT TO KEEP POINTING IN FIXED DIRECTION REGARDLESS OF PHONE ROTATION

            } 
        }

        @Override
        public void onLocationChanged(Location location) {
            tvCurrLat.setText(String.valueOf(location.getLatitude()));
            tvCurrLng.setText(String.valueOf(location.getLongitude()));
            setBearing();
            locationManager.removeUpdates(this);

        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {

        }

        @Override
        public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {

        }

        @Override
        protected void onPause() {
            // Unregister the listener
            super.onPause();
            locationManager.removeUpdates(this);
            mSensorManager.unregisterListener(this);
            ivArrow.setVisibility(View.INVISIBLE);

        }

        @Override
        protected void onResume() {
            super.onResume();
            locationManager.requestLocationUpdates(provider, 1000, 1, this);
            mSensorManager.registerListener(this, mCompass,
                    SensorManager.SENSOR_DELAY_GAME);
        }

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Android docs说，

bearingTo（）

使用WGS84椭球体，所以是的，它考虑了地球曲率

要使罗盘在设备旋转时保持稳定，使用位置传感器是不够的，还应使用磁场传感器。大多数安卓设备都有

---

您需要查看

SensorManager.getOrientation（）

：

谢谢您的回答。。你知道如何完成我在问题中提到的第三部分吗？谢谢@gilonm在textview tvCurrAzim中，当设备旋转时，文本是否会更改？@gilonm如果是，问题在于重新绘制指针，而不是获取设备方向…@gilonm为了使代码更清晰、可读且易于测试，请将与指向箭头相关的所有方法和属性集中在一个单独的类中。它应该存储arrow的当前旋转、角度和动画资源-因此在接收到新方向后，您只需调用定点arrow对象的更新方法，它就可以自己完成所有其他工作。@gilonm我制作了这样一个对象来处理方向更新，看一看