如何平滑地减慢谷歌地图中标记的旋转速度

Question

我用这条线来旋转标记

marker.setRotation((float) bearingBetweenLocations(startPosition, destination));

这会导致突然快速旋转。他们有什么方法可以减慢标记旋转速度

Answer 1

使用喜欢

float bearing = (float) bearingBetweenLocations(startPosition, new LatLng(destination.getLatitude(), destination.getLongitude()));
                        // mMarker.setRotation((float) bearingBetweenLocations();
                        rotateMarker(mMarker, bearing);

方法是

您可以在此处更改旋转标记功能final long duration = 500; // Change duration as you want

 public double bearingBetweenLocations(LatLng latLng1, LatLng latLng2) {
        double PI = 3.14159;
        double lat1 = latLng1.latitude * PI / 180;
        double long1 = latLng1.longitude * PI / 180;
        double lat2 = latLng2.latitude * PI / 180;
        double long2 = latLng2.longitude * PI / 180;

        double dLon = (long2 - long1);

        double y = Math.sin(dLon) * Math.cos(lat2);
        double x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
                * Math.cos(lat2) * Math.cos(dLon);

        double brng = Math.atan2(y, x);

        brng = Math.toDegrees(brng);
        brng = (brng + 360) % 360;

        return brng;
    }


    public void rotateMarker(final Marker marker, final float toRotation) {
        if (!isMarkerRotating) {
            final Handler handler = new Handler();
            final long start = SystemClock.uptimeMillis();
            final float startRotation = marker.getRotation();
            final long duration = 500; // Change duration as you want

            final Interpolator interpolator = new LinearInterpolator();

            handler.post(new Runnable() {
                @Override
                public void run() {
                    isMarkerRotating = true;

                    long elapsed = SystemClock.uptimeMillis() - start;
                    float t = interpolator.getInterpolation((float) elapsed / duration);

                    float rot = t * toRotation + (1 - t) * startRotation;

                    float bearing = -rot > 180 ? rot / 2 : rot;

                    marker.setRotation(bearing);

                    if (t < 1.0) {
                        // Post again 16ms later.
                        handler.postDelayed(this, 4);
                    } else {
                        isMarkerRotating = false;
                    }
                }
            });
        }
    }

希望对你有帮助。