MapBox中的标记方向android

Question

我正在使用mapbox sdk创建一个显示公交车位置的android应用程序。 我想像Uber应用那样根据位置旋转标记。 我怎么能做到这一点？

代码：

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

这里的an example这确实你刚才问什么不同之处，而不是公交车，它跟踪国际空间站实时。标题的计算使用Turf和Mapbox Android Services SDK完成，但如果您只需要这种单一方法，则可以从库中复制该方法。下面是来自例子我上面提到的重要代码：

// 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()) 
    ); 
} 

您也可以使用这个方法，我以前草坪以前用过：

// 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); 
}