kotlin实现弹出Window在屏幕最低端

需求：需要在任意页面的最低端，弹出一个Window

编写一个Window类：

class PopLoadingWindow(layoutInflater: LayoutInflater, weight: Int, height: Int) {

    var mPopWindow: PopupWindow? = null
    var mView: View? = null
    val mTake_New_id: Int = R.id.mine_uploading_btn_new
    val mTake_local_id: Int = R.id.mine_uploading_btn_local
    val mCancel_id: Int = R.id.mine_uploading_btn_cancel

    var mUpLoading_btn_new: Button? = null
    var mUpLoading_btn_local: Button? = null
    var mUpLoading_btn_cancel: Button? = null

    init {
        initView(layoutInflater, weight, height)
    }


    fun initView(layoutInflater: LayoutInflater, w: Int, h: Int) {
        mView = layoutInflater.inflate(R.layout.popue_uploading_window, null)
        mUpLoading_btn_new = mView!!.findViewById(R.id.mine_uploading_btn_new) as Button
        mUpLoading_btn_local = mView!!.findViewById(R.id.mine_uploading_btn_local) as Button
        mUpLoading_btn_cancel = mView!!.findViewById(R.id.mine_uploading_btn_cancel) as Button

        //获取屏幕宽高
        val weight = w
        val height = h * 2 / 5

        mPopWindow = PopupWindow(mView, weight, height);
        mPopWindow!!.isFocusable = true
        mPopWindow!!.isOutsideTouchable = true   //点击外部popueWindow消失
        mPopWindow!!.animationStyle = R.style.Anim_style

    }

    fun dismiss() {
        mPopWindow!!.dismiss()

    }

    fun show() {
        //确定Window显示的位置，bottom和x=0，y=0这样的位置
        mPopWindow!!.showAtLocation(mView, Gravity.BOTTOM, 0, 0);
    }

}

调用该类：

       //初始化，上传本地视频和照片页面
        val layoutInflater = activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        // 获取屏幕宽高
        val weight = resources.displayMetrics.widthPixels
        val height = resources.displayMetrics.heightPixels
       //初始化该对象
        mPopWindow = PopLoadingWindow(layoutInflater, weight, height)
        mPopWindow!!.mUpLoading_btn_cancel!!.setOnClickListener(this)
        mPopWindow!!.mUpLoading_btn_local!!.setOnClickListener(this)
        mPopWindow!!.mUpLoading_btn_new!!.setOnClickListener(this)