自定义动画效果：两次心跳

ViewAnimator.animate(view)
                .repeatCount(-1)
                .repeatMode(ViewAnimator.RESTART)
                .duration(4000)
                .scaleX(1, 0.85f, 1.25f, 1, 0.85f, 1, 1)
                .scaleY(1, 0.85f, 1.25f, 1, 0.85f, 1, 1)
                .interpolator(new OvershootInterpolator())
                .start();