Android 使用GroundOverlay的脉冲动画
我需要通过脉冲动画显示位置A和位置B。我能够实现这一点，使用下面的代码。但我面临的问题是，当缩放级别发生变化时，GroundOverlay会改变其大小。如果位置A和B彼此接近（即地图放大级别高），则脉冲半径太大。当我缩小时，它会变得太小 如何在不考虑地图缩放级别的情况下保持覆盖的大小不变 以下代码在此引用： [这是我在两个位置相距较远时得到的结果][] 对于第一个图像，如果我放大，那么我会看到脉冲动画Android 使用GroundOverlay的脉冲动画,android,google-maps,animation,gmsgroundoverlay,Android,Google Maps,Animation,Gmsgroundoverlay,我需要通过脉冲动画显示位置A和位置B。我能够实现这一点，使用下面的代码。但我面临的问题是，当缩放级别发生变化时，GroundOverlay会改变其大小。如果位置A和B彼此接近（即地图放大级别高），则脉冲半径太大。当我缩小时，它会变得太小 如何在不考虑地图缩放级别的情况下保持覆盖的大小不变 以下代码在此引用： [这是我在两个位置相距较远时得到的结果][] 对于第一个图像，如果我放大，那么我会看到脉冲动画 有没有一种方法可以在不考虑缩放级别的情况下保持脉冲半径不变？因此，假设您希望覆盖圆半径为固
有没有一种方法可以在不考虑缩放级别的情况下保持脉冲半径不变？因此，假设您希望覆盖圆半径为固定尺寸（相对于 屏幕像素），例如屏幕宽度的1/10（在当前缩放时） 本例使用宽度作为缩放轴，但也可以使用高度或对角线（通过使用投影的不同点） “远”的用法可以替换为“近”——它用来解释倾斜，所以你必须进行实验 所以现在你的资源值是一个比例因子，而不是一个绝对半径值-所以在这个例子中，你可以将资源值设置为0.10F，并使用上面的硬编码 如果希望脉冲（和叠加）在缩放后/缩放过程中工作，则需要使用“onCameraIdle”事件更新叠加圆的宽度（circle.setWidth（scaledRadius））-使用与上述scaledRadius相同的计算，例如：
public void onCameraIdle() {
if (circle != null) {
// compute scaled radius as in above code...
// The 1-argument version is specifically width
circle.setDimensions(scaledRadius);
}
}
这是因为
GroundOverlayGroundOverlayGroundOverlayshowRipples（）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;
}
}
计算“半径”作为屏幕投影大小的函数（请参见map.getProjection（）。
public void onCameraIdle() {
if (circle != null) {
// compute scaled radius as in above code...
// The 1-argument version is specifically width
circle.setDimensions(scaledRadius);
}
}
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;
}
}