我想实现平滑过渡,模拟汽车标记在地图上移动。
在Android Map API V2中是否可以动画化标记?
在Android Map API V2中是否可以动画化标记?
我尝试了所有提供的版本,但都无法满足我的需求,所以我实现了自己的定制解决方案。它可以同时提供位置和旋转动画。
/**
* Method to animate marker to destination location
* @param destination destination location (must contain bearing attribute, to ensure
* marker rotation will work correctly)
* @param marker marker to be animated
*/
public static void animateMarker(Location destination, Marker marker) {
if (marker != null) {
LatLng startPosition = marker.getPosition();
LatLng endPosition = new LatLng(destination.getLatitude(), destination.getLongitude());
float startRotation = marker.getRotation();
LatLngInterpolator latLngInterpolator = new LatLngInterpolator.LinearFixed();
ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, 1);
valueAnimator.setDuration(1000); // duration 1 second
valueAnimator.setInterpolator(new LinearInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override public void onAnimationUpdate(ValueAnimator animation) {
try {
float v = animation.getAnimatedFraction();
LatLng newPosition = latLngInterpolator.interpolate(v, startPosition, endPosition);
marker.setPosition(newPosition);
marker.setRotation(computeRotation(v, startRotation, destination.getBearing()));
} catch (Exception ex) {
// I don't care atm..
}
}
});
valueAnimator.start();
}
}
计算指定动画部分的旋转。标记会朝离起始旋转更近的方向旋转:
private static float computeRotation(float fraction, float start, float end) {
float normalizeEnd = end - start; // rotate start to 0
float normalizedEndAbs = (normalizeEnd + 360) % 360;
float direction = (normalizedEndAbs > 180) ? -1 : 1; // -1 = anticlockwise, 1 = clockwise
float rotation;
if (direction > 0) {
rotation = normalizedEndAbs;
} else {
rotation = normalizedEndAbs - 360;
}
float result = fraction * rotation + start;
return (result + 360) % 360;
}
LatLngInterpolator
:private interface LatLngInterpolator {
LatLng interpolate(float fraction, LatLng a, LatLng b);
class LinearFixed implements LatLngInterpolator {
@Override
public LatLng interpolate(float fraction, LatLng a, LatLng b) {
double lat = (b.latitude - a.latitude) * fraction + a.latitude;
double lngDelta = b.longitude - a.longitude;
// Take the shortest path across the 180th meridian.
if (Math.abs(lngDelta) > 180) {
lngDelta -= Math.signum(lngDelta) * 360;
}
double lng = lngDelta * fraction + a.longitude;
return new LatLng(lat, lng);
}
}
}
setBearing(float)
或 bearingTo(Location)
方法在传递的 Location destination
参数上正确设置方位。 - skywall尝试以下代码来动画化Google Map V2上的标记。您需要使用Interpolator
类将动画应用于标记,并在处理程序中处理它,如下所示:
public void animateMarker(final Marker marker, final LatLng toPosition,
final boolean hideMarker) {
final Handler handler = new Handler();
final long start = SystemClock.uptimeMillis();
Projection proj = mGoogleMapObject.getProjection();
Point startPoint = proj.toScreenLocation(marker.getPosition());
final LatLng startLatLng = proj.fromScreenLocation(startPoint);
final long duration = 500;
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));
if (t < 1.0) {
// Post again 16ms later.
handler.postDelayed(this, 16);
} else {
if (hideMarker) {
marker.setVisible(false);
} else {
marker.setVisible(true);
}
}
}
});
}
我们刚刚实现了一个新版本,请尝试使用此版本。
public class MarkerAnimation {
static GoogleMap map;
ArrayList<LatLng> _trips = new ArrayList<>() ;
Marker _marker;
LatLngInterpolator _latLngInterpolator = new LatLngInterpolator.Spherical();
public void animateLine(ArrayList<LatLng> Trips,GoogleMap map,Marker marker,Context current){
_trips.addAll(Trips);
_marker = marker;
animateMarker();
}
public void animateMarker() {
TypeEvaluator<LatLng> typeEvaluator = new TypeEvaluator<LatLng>() {
@Override
public LatLng evaluate(float fraction, LatLng startValue, LatLng endValue) {
return _latLngInterpolator.interpolate(fraction, startValue, endValue);
}
};
Property<Marker, LatLng> property = Property.of(Marker.class, LatLng.class, "position");
ObjectAnimator animator = ObjectAnimator.ofObject(_marker, property, typeEvaluator, _trips.get(0));
//ObjectAnimator animator = ObjectAnimator.o(view, "alpha", 0.0f);
animator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationCancel(Animator animation) {
// animDrawable.stop();
}
@Override
public void onAnimationRepeat(Animator animation) {
// animDrawable.stop();
}
@Override
public void onAnimationStart(Animator animation) {
// animDrawable.stop();
}
@Override
public void onAnimationEnd(Animator animation) {
// animDrawable.stop();
if (_trips.size() > 1) {
_trips.remove(0);
animateMarker();
}
}
});
animator.setDuration(300);
animator.start();
}
LatLngInterpolator类是由Google开发人员预先编写的,您可以按照以下方式使用:
public interface LatLngInterpolator {
public LatLng interpolate(float fraction, LatLng a, LatLng b);
public class Spherical implements LatLngInterpolator {
@Override
public LatLng interpolate(float fraction, LatLng from, LatLng to) {
// http://en.wikipedia.org/wiki/Slerp
double fromLat = toRadians(from.latitude);
double fromLng = toRadians(from.longitude);
double toLat = toRadians(to.latitude);
double toLng = toRadians(to.longitude);
double cosFromLat = cos(fromLat);
double cosToLat = cos(toLat);
// Computes Spherical interpolation coefficients.
double angle = computeAngleBetween(fromLat, fromLng, toLat, toLng);
double sinAngle = sin(angle);
if (sinAngle < 1E-6) {
return from;
}
double a = sin((1 - fraction) * angle) / sinAngle;
double b = sin(fraction * angle) / sinAngle;
// Converts from polar to vector and interpolate.
double x = a * cosFromLat * cos(fromLng) + b * cosToLat * cos(toLng);
double y = a * cosFromLat * sin(fromLng) + b * cosToLat * sin(toLng);
double z = a * sin(fromLat) + b * sin(toLat);
// Converts interpolated vector back to polar.
double lat = atan2(z, sqrt(x * x + y * y));
double lng = atan2(y, x);
return new LatLng(toDegrees(lat), toDegrees(lng));
}
private double computeAngleBetween(double fromLat, double fromLng, double toLat, double toLng) {
// Haversine's formula
double dLat = fromLat - toLat;
double dLng = fromLng - toLng;
return 2 * asin(sqrt(pow(sin(dLat / 2), 2) +
cos(fromLat) * cos(toLat) * pow(sin(dLng / 2), 2)));
}
}
}
MarkerAnimation.animateLine(TripPoints,map,MovingMarker,context);
您只需要添加这个类并传递一个位置,您可以通过使用Fusedlocationproviderclient轻松获取。
public class LocationMoveAnim {
public static void startAnimation(final Marker marker, final GoogleMap googleMap, final LatLng startPosition,
final LatLng endPosition,final GoogleMap.CancelableCallback callback) {
ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, 1);
int duration = 500;
valueAnimator.setDuration(duration);
final LatLngInterpolatorNew latLngInterpolator = new LatLngInterpolatorNew.LinearFixed();
valueAnimator.setInterpolator(new LinearInterpolator());
valueAnimator.addUpdateListener(valueAnimator1 -> {
float v = valueAnimator1.getAnimatedFraction();
LatLng newPos = latLngInterpolator.interpolate(v, startPosition, endPosition);
marker.setPosition(newPos);
marker.setAnchor(0.5f, 0.5f);
marker.setRotation((float) bearingBetweenLocations(startPosition, endPosition));
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(newPos,20F));
callback.onFinish();
});
valueAnimator.start();
}
private static 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 interface LatLngInterpolatorNew {
LatLng interpolate(float fraction, LatLng a, LatLng b);
class LinearFixed implements LatLngInterpolatorNew {
@Override
public LatLng interpolate(float fraction, LatLng a, LatLng b) {
double lat = (b.latitude - a.latitude) * fraction + a.latitude;
double lngDelta = b.longitude - a.longitude;
// Take the shortest path across the 180th meridian.
if (Math.abs(lngDelta) > 180) {
lngDelta -= Math.signum(lngDelta) * 360;
}
double lng = lngDelta * fraction + a.longitude;
return new LatLng(lat, lng);
}
}
}
}