底部弹窗使用应该很多吧，最近在项目中频繁用到，索性就封装分享出来，像抖音的评论、分享，应用还是挺多的。

open class BaseBottomDialogFragment : BottomSheetDialogFragment() {
override fun onStart() {
    super.onStart()
    val dialogHeight = getDialogHeight(context!!)
    // 点击外面允许取消
    dialog.setCanceledOnTouchOutside(true)
    dialog.window!!.setGravity(Gravity.BOTTOM)
    val bottomSheetDialog = dialog as BottomSheetDialog
    val view = bottomSheetDialog.window!!.findViewById<View>(android.support.design.R.id.design_bottom_sheet)
    val layoutParams = view.layoutParams
    layoutParams.height = dialogHeight
    view.layoutParams = layoutParams
    view.setBackgroundResource(R.color.transparent)
    BottomSheetBehavior.from(view).peekHeight = getPeekHeight()
}

/**
 * 得到屏幕的高
 *
 * @param context
 * @return
 */
protected fun getScreenHeight(context: Context): Int {
    val wm = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
    return (wm.defaultDisplay.height)
}

/**
 * 底部弹窗的高度
 * 子类可以自己实现，定义高度
 */
open fun getDialogHeight(context: Context) = (context.resources.displayMetrics.heightPixels * 0.6).toInt()

/**
 * 底部弹窗弹出时的高度，需要注意的是如果PeekHeight大于tDialogHeight时，弹窗会显示不全
 */
open fun getPeekHeight() = (getScreenHeight(context!!) * 0.7).toInt()
}

这是我在项目中使用的底部弹窗list表：

abstract class BaseListBottomDialogFragment : BaseBottomDialogFragment() {

    var headView: View? = null

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    val rootView: View = inflater.inflate(getLayoutId(), container, false)
    val llContent = rootView.findViewById<View>(R.id.ll_content) as LinearLayout
    headView = setHeader(llContent)

    if (headView != null) {
        llContent.addView(headView, 0, headView!!.layoutParams)
    }

    val recyclerView = rootView.findViewById<View>(R.id.recyclerView) as RecyclerView
    recyclerView.layoutManager = getLayoutManager(recyclerView)
    recyclerView.adapter = getAdapter(recyclerView)

    return rootView
}


override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
}


override fun getPeekHeight(): Int {
    return super.getPeekHeight()
}

open fun getLayoutId() = if (canHeadScroll()) {
    R.layout.dialog_base_bottom_list_scroll
} else {
    R.layout.dialog_base_bottom_list_unscroll
}

protected fun canHeadScroll() = false


protected abstract fun getLayoutManager(recyclerView: RecyclerView): RecyclerView.LayoutManager

/**
 * 自定义Adapter
 *
 * @param recyclerView
 * @return
 */
protected abstract fun getAdapter(recyclerView: RecyclerView): RecyclerView.Adapter<*>?


/**
 * 添加头布局
 *
 * @param container
 * @return
 */
open fun setHeader(container: ViewGroup): View? {
    return null
}

}

当然不只是RecyclerView，也可以是ViewPager，但是ViewPager会影响弹窗的滑动闭关，暂时还有找到解决方案。