Question

我正在创建安卓应用，它使用mapbox sdk显示地图中公交车的位置。我想像Uber app一样根据位置旋转标记。我怎么能实现这个目标？

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除了公共汽车之外，还能满足您的要求，它实时跟踪国际空间站。使用Turf和Mapbox Android Services SDK完成标题的计算，但如果您只需要该方法，则只需从库中复制该方法即可。以下是我上面提到的示例中的重要代码：

// 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())
    );
}

你也可以使用我之前在Turf之前使用过的方法：

// 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);
}

MapBox android中的标记方向

1 个答案: