1. 确认 bottom sheet 是否被正确地关闭，可以通过给 BottomSheetBehavior 设置 StateCallback 监听状态变化来检查。

bottomSheetBehavior.setBottomSheetCallback(object : BottomSheetBehavior.BottomSheetCallback() {
    override fun onStateChanged(bottomSheet: View, newState: Int) {
        if (newState == BottomSheetBehavior.STATE_HIDDEN) {
            // do something
        }
    }
    override fun onSlide(bottomSheet: View, slideOffset: Float) {}
})

2. 如果 bottom sheet 还未完全隐藏，可以通过设置 View 的 visibility 为 View.GONE 或者对 bottom sheet 执行动画将其移出屏幕。

// 设置 visibility
bottomSheet.visibility = View.GONE

// 执行动画
ObjectAnimator.ofFloat(bottomSheet, "translationY", 0f, bottomSheet.height.toFloat()).apply {
    duration = 300L
    interpolator = AccelerateInterpolator()
    addListener(object : AnimatorListenerAdapter() {
        override fun onAnimationEnd(animation: Animator?) {
            bottomSheet.visibility = View.GONE
        }
    })
    start()
}