Google Maps Android API v2:借助ValueAnimator可视化搜索半径

Question

我想在Google地图视图中添加一个动画圆圈,类似于您在此图片上看到的圆圈.

圆圈应从中心脉动到最大半径,表示当前用户的位置和搜索区域.

这是相关的代码块

Circle circle = mMap.addCircle(new CircleOptions()
     .center(new LatLng(lat, lon))
     .strokeColor(Color.CYAN).radius(1000));
    valueAnimator = new ValueAnimator();
    valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {
        float animatedFraction = valueAnimator.getAnimatedFraction();
         circle.setRadius(animatedFraction * 1000);
         circle.setStrokeWidth(1 + animatedFraction * 7);
         }
        });

使用此代码,我只能看到没有任何动画的静态圆形笔划.

任何帮助将不胜感激.提前致谢.

Answer 1

简单:)

    final Circle circle = MAP.addCircle(new CircleOptions().center(EGYPT)
            .strokeColor(Color.CYAN).radius(100));

    ValueAnimator vAnimator = new ValueAnimator();
    vAnimator.setRepeatCount(ValueAnimator.INFINITE);
    vAnimator.setRepeatMode(ValueAnimator.RESTART);  /* PULSE */
    vAnimator.setIntValues(0, 100);
    vAnimator.setDuration(1000);
    vAnimator.setEvaluator(new IntEvaluator());
    vAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
    vAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {
            float animatedFraction = valueAnimator.getAnimatedFraction();
            // Log.e("", "" + animatedFraction);
            circle.setRadius(animatedFraction * 100);
        }
    });
    vAnimator.start();