我需要通过脉冲动画显示位置A和位置B。我可以使用以下代码实现这一目标。但是我面临的问题是，当缩放级别更改时，GroundOverlay会更改其大小。如果位置A和B彼此靠近（即地图放大级别较高），则脉冲半径太大。当我缩小时，它变得太小。
无论地图的缩放级别如何，都应保持叠加层的大小不变。
以下代码是从此处引用的：Animated Transparent Circle on Google Maps v2 is NOT animating correctly
private void showRipples(LatLng latLng, int color) {
GradientDrawable d = new GradientDrawable();
d.setShape(GradientDrawable.OVAL);
d.setSize(500, 500);
d.setColor(ContextCompat.getColor(Activity.this, color));
d.setStroke(0, Color.TRANSPARENT);
final Bitmap bitmap = Bitmap.createBitmap(d.getIntrinsicWidth()
, d.getIntrinsicHeight()
, Bitmap.Config.ARGB_8888);
// Convert the drawable to bitmap
final Canvas canvas = new Canvas(bitmap);
d.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
d.draw(canvas);
// Radius of the circle
final int radius = getResources().getDimensionPixelSize(R.dimen.ripple_radius);
// Add the circle to the map
final GroundOverlay circle = googleMap.addGroundOverlay(new GroundOverlayOptions()
.position(latLng, 2 * radius).image(BitmapDescriptorFactory.fromBitmap(bitmap)));
// Prep the animator
PropertyValuesHolder radiusHolder = PropertyValuesHolder.ofFloat("radius", 1, radius);
PropertyValuesHolder transparencyHolder = PropertyValuesHolder.ofFloat("transparency", 0, 1);
ValueAnimator valueAnimator = new ValueAnimator();
valueAnimator.setRepeatCount(ValueAnimator.INFINITE);
valueAnimator.setRepeatMode(ValueAnimator.RESTART);
valueAnimator.setValues(radiusHolder, transparencyHolder);
valueAnimator.setDuration(DURATION);
valueAnimator.setEvaluator(new FloatEvaluator());
valueAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
float animatedRadius = (float) valueAnimator.getAnimatedValue("radius");
float animatedAlpha = (float) valueAnimator.getAnimatedValue("transparency");
circle.setDimensions(animatedRadius * 2);
circle.setTransparency(animatedAlpha);
}
});
// start the animation
valueAnimator.start();
}
[这是当两个位置相互远离时得到的结果] [] 1
If the two locations are close to each other I get this behaviour
对于第一个图像，如果我放大，则可以看到脉冲动画。
有什么方法可以使脉冲半径保持不变，而不管缩放级别如何？
最佳答案
发生这种情况是因为GroundOverlay与Google地图一起缩放。为避免这种情况，您应该为每个缩放级别重新创建覆盖图，并为该缩放级别和纬度（示例源代码中的meters_to_pixels）校正半径。为了避免GroundOverlay重新创建，应存储创建的GroundOverlay对象并在创建新对象之前将其删除。为此，您需要在showRipples()方法中进行一些更改-它应该返回创建的叠加层。完整的源代码，例如带有一个标记的代码：
public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
private static final String TAG = MainActivity.class.getSimpleName();
private final LatLng RED_MARKER = new LatLng(-37.884312, 145.000623);
private GoogleMap mGoogleMap;
private MapFragment mMapFragment;
private GroundOverlay mRedPoint = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mMapFragment = (MapFragment) getFragmentManager()
.findFragmentById(R.id.map_fragment);
mMapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mGoogleMap = googleMap;
mGoogleMap.setOnCameraIdleListener(new GoogleMap.OnCameraIdleListener() {
@Override
public void onCameraIdle() {
// if overlay already exists - remove it
if (mRedPoint != null) {
mRedPoint.remove();
}
mRedPoint = showRipples(RED_MARKER, Color.RED);
}
});
mGoogleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(RED_MARKER, 16));
}
private GroundOverlay showRipples(LatLng latLng, int color) {
GradientDrawable d = new GradientDrawable();
d.setShape(GradientDrawable.OVAL);
d.setSize(500, 500);
d.setColor(color);
d.setStroke(0, Color.TRANSPARENT);
final Bitmap bitmap = Bitmap.createBitmap(d.getIntrinsicWidth()
, d.getIntrinsicHeight()
, Bitmap.Config.ARGB_8888);
// Convert the drawable to bitmap
final Canvas canvas = new Canvas(bitmap);
d.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
d.draw(canvas);
// Radius of the circle for current zoom level and latitude (because Earth is sphere at first approach)
double meters_to_pixels = (Math.cos(mGoogleMap.getCameraPosition().target.latitude * Math.PI /180) * 2 * Math.PI * 6378137) / (256 * Math.pow(2, mGoogleMap.getCameraPosition().zoom));
final int radius = (int)(meters_to_pixels * getResources().getDimensionPixelSize(R.dimen.ripple_radius));
// Add the circle to the map
final GroundOverlay circle = mGoogleMap.addGroundOverlay(new GroundOverlayOptions()
.position(latLng, 2 * radius).image(BitmapDescriptorFactory.fromBitmap(bitmap)));
// Prep the animator
PropertyValuesHolder radiusHolder = PropertyValuesHolder.ofFloat("radius", 1, radius);
PropertyValuesHolder transparencyHolder = PropertyValuesHolder.ofFloat("transparency", 0, 1);
ValueAnimator valueAnimator = new ValueAnimator();
valueAnimator.setRepeatCount(ValueAnimator.INFINITE);
valueAnimator.setRepeatMode(ValueAnimator.RESTART);
valueAnimator.setValues(radiusHolder, transparencyHolder);
valueAnimator.setDuration(1000);
valueAnimator.setEvaluator(new FloatEvaluator());
valueAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
float animatedRadius = (float) valueAnimator.getAnimatedValue("radius");
float animatedAlpha = (float) valueAnimator.getAnimatedValue("transparency");
circle.setDimensions(animatedRadius * 2);
circle.setTransparency(animatedAlpha);
}
});
// start the animation
valueAnimator.start();
return circle;
}
}