Question

我想实现三件事：

1）基于位置传感器实现指南针+获取当前坐标

2）将方位设定为固定目的地

3）一旦设定了轴承，我想设置一个红色罗盘针，无论手机旋转如何，都会继续指向固定轴承。

到目前为止，我已经完成了1 + 2.关于3 - 我设法将针指向正确的方向，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，但我无法做到这一点。

还有一个问题：如果bearingTo（）方法计算两个位置之间的度数 - 它是否考虑了地球曲率？如果没有，这只能在近距离内准确...希望如此： - ）

我将不胜感激。

这是我的代码 - 检查注释以获得解释。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);
        }

Answer 1

Android文档说bearingTo()使用WGS84椭球，所以是的，它会考虑地球曲率。

为了使您的指南针在设备旋转时保持稳定，使用位置传感器是不够的，您还应该使用磁场传感器。大多数Android设备都有它们。

您需要SensorManager.getOrientation()查看：http://developer.android.com/reference/android/hardware/SensorManager.html

两点之间的位置承载+地球曲率问题

1 个答案: