我正在开发罗盘应用程序,我希望指南针指向特定的纬度经度位置,而不是通常的北方.我发现有一些
questions与我的问题有关,但我没有办法让他们为我工作.这是我的代码:
public class MainActivity extends AppCompatActivity implements SensorEventListener { private ImageView image; private float currentDegree = 0f; private SensorManager mSensorManager; private TextView tvHeading; private Location location = new Location("A"); private Location target = new Location("B"); private LocationManager locationManager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); image = (ImageView) findViewById(R.id.imageViewCompass); tvHeading = (TextView) findViewById(R.id.tvHeading); mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE); location.setLatitude(54.903535); location.setLongitude(23.979342); target.setLatitude(54.904618); target.setLongitude(23.978782); } @Override protected void onResume() { super.onResume(); mSensorManager.registerListener(this,mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),SensorManager.SENSOR_DELAY_GAME); } @Override protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); // to stop the listener and save battery } @Override public void onSensorChanged(SensorEvent event) { float degree = Math.round(event.values[0]); tvHeading.setText("Heading: " + Float.toString(degree) + " degrees"); RotateAnimation ra = new RotateAnimation( currentDegree,-degree,Animation.RELATIVE_TO_SELF,0.5f,0.5f); ra.setDuration(210); ra.setFillAfter(true); image.startAnimation(ra); currentDegree = -degree; } @Override public void onAccuracyChanged(Sensor sensor,int accuracy) { // not in use } }
目前我的指针只显示在北方,而不是我的编码目标位置.
解决方法
我想我找到了办法:
这是我已经改变以获得预期行为的方法(基于 this问题和CookieMonster答案)
这是我已经改变以获得预期行为的方法(基于 this问题和CookieMonster答案)
@Override public void onSensorChanged(SensorEvent event) { // get the angle around the z-axis rotated float degree = Math.round(event.values[0]); degree += geoField.getDeclination(); float bearing = location.bearingTo(target); degree = (bearing - degree) * -1; degree = normalizeDegree(degree); tvHeading.setText("Heading: " + Float.toString(degree) + " degrees"); // create a rotation animation (reverse turn degree degrees) RotateAnimation ra = new RotateAnimation( currentDegree,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 image.startAnimation(ra); currentDegree = -degree; } private float normalizeDegree(float value) { if (value >= 0.0f && value <= 180.0f) { return value; } else { return 180 + (180 + value); } }