MapBox中的標記方向android

Question

我正在使用mapbox sdk創建一個顯示公交車位置的android應用程序。 我想像Uber應用那樣根據位置旋轉標記。 我怎麼能做到這一點？

代碼：

IconFactory iconFactory = IconFactory.getInstance(navigationActivity.this); 
    Drawable iconDrawable = ContextCompat.getDrawable(navigationActivity.this, R.drawable.bus); 
    Icon icon = iconFactory.fromDrawable(iconDrawable); 
    map.clear(); 
    CameraPosition position = new CameraPosition.Builder() 
      .target(new LatLng(lat,lon)) // Sets the new camera position 
      .zoom(16) // Sets the zoom 
      .bearing(180) // Rotate the camera 
      .tilt(30) // Set the camera tilt 
      .build(); // Creates a CameraPosition from the builder 
    map.animateCamera(CameraUpdateFactory 
      .newCameraPosition(position), 7000); 
    final Marker marker = map.addMarker(new MarkerOptions() 
      .position(new LatLng(lat,lon)) 
      .title("You!") 
      .snippet("YOu are Currently here.")); 
    marker.setIcon(icon); 

Answer 1

這裏的an example這確實你剛纔問什麼不同之處，而不是公交車，它跟蹤國際空間站實時。標題的計算使用Turf和Mapbox Android Services SDK完成，但如果您只需要這種單一方法，則可以從庫中複製該方法。下面是來自例子我上面提到的重要代碼：

// Make sure you are using marker views so you can update the rotation. 
marker.setRotation((float) computeHeading(marker.getPosition(), position)); 

... 

public static double computeHeading(LatLng from, LatLng to) { 
// Compute bearing/heading using Turf and return the value. 
    return TurfMeasurement.bearing(
     Position.fromCoordinates(from.getLongitude(), from.getLatitude()), 
     Position.fromCoordinates(to.getLongitude(), to.getLatitude()) 
    ); 
} 

您也可以使用這個方法，我以前草坪以前用過：

// Returns the heading from one LatLng to another LatLng. Headings are. Expressed in degrees 
// clockwise from North within the range [-180,180). The math for this method came from 
// http://williams.best.vwh.net/avform.htm#Crs I only converted it to Java. 
public static double computeHeading(LatLng from, LatLng to) { 
    double fromLat = Math.toRadians(from.getLatitude()); 
    double fromLng = Math.toRadians(from.getLongitude()); 
    double toLat = Math.toRadians(to.getLatitude()); 
    double toLng = Math.toRadians(to.getLongitude()); 
    double dLng = toLng - fromLng; 
    double heading = Math.atan2(Math.sin(dLng) * Math.cos(toLat), 
      Math.cos(fromLat) * Math.sin(toLat) - Math.sin(fromLat) * Math.cos(toLat) * Math.cos(dLng)); 
    return (Math.toDegrees(heading) >= -180 && Math.toDegrees(heading) < 180) ? 
      Math.toDegrees(heading) : ((((Math.toDegrees(heading) + 180) % 360) + 360) % 360 + -180); 
}