Marker Animation on Google Maps Android not working

问题

I am trying to animate my marker instead of making it jump between the 2 points. For some reason the animation does not work.

Every time I get a new current location, I call the below code.

if (currentLatitude != 0 && currentLongitude != 0) {
            String actualRideStartTime = "";
            if (currentRideTracking.getActualRideStartTime() != 0) {
                actualRideStartTime = TIME_FORMAT.format(currentRideTracking
                        .getActualRideStartTime());
            }
            vehicleLocation = new LatLng(currentLatitude, currentLongitude);
            markerOptions = new MarkerOptions().
                    .position(vehicleLocation);    

            animateMarker(map.addMarker(markerOptions), vehicleLocation, false);
//            builder.include(vehicleLocation);
        }

AnimateMarker method

public void animateMarker(final Marker marker, final LatLng toPosition,
                              final boolean hideMarker) {
        final Handler handler = new Handler();
        final long start = SystemClock.uptimeMillis();
        Projection proj = map.getProjection();
        Point startPoint = proj.toScreenLocation(marker.getPosition());
        final LatLng startLatLng = proj.fromScreenLocation(startPoint);
        final long duration = God.DRIVER_LOCATION_UPDATE_FREQUENCY;
        final Interpolator interpolator = new LinearInterpolator();
        handler.post(new Runnable() {
            @Override
            public void run() {
                long elapsed = SystemClock.uptimeMillis() - start;
                float t = interpolator.getInterpolation((float) elapsed
                        / duration);
                double lng = t * toPosition.longitude + (1 - t)
                        * startLatLng.longitude;
                double lat = t * toPosition.latitude + (1 - t)
                        * startLatLng.latitude;
                marker.setPosition(new LatLng(lat, lng));
                Log.d(God.LOG_TAG, ">"+lat+"<"+lng) ;
                if (t < 1.0) {
                    // Post again 16ms later.
                    handler.postDelayed(this, 16);
                } else {
                    if (hideMarker) {
                        marker.setVisible(false);
                    } else {
                        marker.setVisible(true);
                        marker.showInfoWindow();
                    }
                }
            }
        });
    }

I tried commenting out // builder.include(vehicleLocation); but yet the smooth movement dont happen, instead it jumps ahead just like it used to.

Edit : Does the frequency of updates matter ? I am using googleapiclient, so I dont know how often the updates come. Maximum wait time has been set to God.DRIVER_LOCATION_UPDATE_FREQUENCY, which is used in the duration in the animateMarker method.

回答1:

You can smooth animation for marker from start to end smth like this:

LatLng[] line = bezier(startPosition, endPosition, 0, 0, true);
Marker marker = mMap.addMarker(new MarkerOptions().position(startPosition));
animateMarker(marker, 0, line);

and

 private static void animateMarker(final Marker marker, final int current, final LatLng[] line) {
    if (line == null || line.length == 0 || current >= line.length) {
        return;
    }

    ObjectAnimator animator = ObjectAnimator.ofObject(marker, property, typeEvaluator, line[current]);
    animator.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animation) {

        }

        @Override
        public void onAnimationEnd(Animator animation) {
            animateMarker(marker, current + 1, line);
        }

        @Override
        public void onAnimationCancel(Animator animation) {

        }

        @Override
        public void onAnimationRepeat(Animator animation) {

        }
    });

    animator.setDuration(DURATION);
    animator.start();
}

private static LatLng[] bezier(LatLng p1, LatLng p2, double arcHeight, double skew, boolean up) {
    ArrayList<LatLng> list = new ArrayList<>();
    try {
        if (p1.longitude > p2.longitude) {
            LatLng tmp = p1;
            p1 = p2;
            p2 = tmp;
        }

        LatLng c = new LatLng((p1.latitude + p2.latitude) / 2, (p1.longitude + p2.longitude) / 2);

        double cLat = c.latitude;
        double cLon = c.longitude;

        //add skew and arcHeight to move the midPoint
        if (Math.abs(p1.longitude - p2.longitude) < 0.0001) {
            if (up) {
                cLon -= arcHeight;
            } else {
                cLon += arcHeight;
                cLat += skew;
            }
        } else {
            if (up) {
                cLat += arcHeight;
            } else {
                cLat -= arcHeight;
                cLon += skew;
            }
        }

        list.add(p1);
        //calculating points for bezier
        double tDelta = 1.0 / 10;
        CartesianCoordinates cart1 = new CartesianCoordinates(p1);
        CartesianCoordinates cart2 = new CartesianCoordinates(p2);
        CartesianCoordinates cart3 = new CartesianCoordinates(cLat, cLon);

        for (double t = 0; t <= 1.0; t += tDelta) {
            double oneMinusT = (1.0 - t);
            double t2 = Math.pow(t, 2);

            double y = oneMinusT * oneMinusT * cart1.y + 2 * t * oneMinusT * cart3.y + t2 * cart2.y;
            double x = oneMinusT * oneMinusT * cart1.x + 2 * t * oneMinusT * cart3.x + t2 * cart2.x;
            double z = oneMinusT * oneMinusT * cart1.z + 2 * t * oneMinusT * cart3.z + t2 * cart2.z;
            LatLng control = CartesianCoordinates.toLatLng(x, y, z);
            list.add(control);
        }

        list.add(p2);
    } catch (Exception e) {
        Log.e(TAG, "bezier error : ", e);
    }

    LatLng[] result = new LatLng[list.size()];
    result = list.toArray(result);

    return result;
}

Please, see full example on my GitHub

来源：https://stackoverflow.com/questions/39139664/marker-animation-on-google-maps-android-not-working