Route.java 文件源码

@Override
    public void onSensorChanged(SensorEvent event) {

    // get the angle around the z-axis rotated
        if (event.sensor == mMagneticSensor) {
            System.arraycopy(event.values, 0, mLastMagnetometer, 0, event.values.length);
            mLastMagnetometerSet = true;
        } else if (event.sensor == mAccelerometer) {
            System.arraycopy(event.values, 0, mLastAccelerometer, 0, event.values.length);
            mLastAccelerometerSet = true;
        }

        if (mLastAccelerometerSet && mLastMagnetometerSet) {
            SensorManager.getRotationMatrix(mR, null, mLastAccelerometer, mLastMagnetometer);
            SensorManager.getOrientation(mR, mOrientation);
            float azimuthInRadians = mOrientation[0];

            float azimuthInDegress = (float) (Math.toDegrees(azimuthInRadians) + 360) % 360;

            mTargetDirection = azimuthInDegress;
        }

        float azimuth = -mTargetDirection;
        GeomagneticField geoField = new GeomagneticField( Double
                .valueOf( mLastLocation.getLatitude() ).floatValue(), Double
                .valueOf( mLastLocation.getLongitude() ).floatValue(),
                Double.valueOf( mLastLocation.getAltitude() ).floatValue(),
                System.currentTimeMillis() );
        if(geoField.getDeclination()<0) {
            azimuth += geoField.getDeclination(); // converts magnetic north into true north
        }else{
            azimuth -= geoField.getDeclination();
        }
        //Correct the azimuth
        azimuth = (azimuth+360) % 360;
        //get the bearing
        float y = (float)Math.sin(Math.toRadians(target.getLongitude()-mLastLocation.getLongitude())) * (float)Math.cos(Math.toRadians(target.getLatitude()));
        float x = (float)Math.cos(Math.toRadians(mLastLocation.getLatitude()))*(float)Math.sin(Math.toRadians(target.getLatitude())) -
                (float)Math.sin(Math.toRadians(mLastLocation.getLatitude()))*(float)Math.cos(Math.toRadians(target.getLatitude()))*(float)Math.cos(Math.toRadians(target.getLongitude()-mLastLocation.getLongitude()));
        float bearing = (float)Math.toDegrees(Math.atan2(y, x));
    image.setRotation(azimuth+bearing);
}