關于PopupWindow迹淌，首先要解決popupwindow在Android7.0顯示錯誤的問題

open class PopupWindowV24 : PopupWindow {
    constructor(context: Context?) : super(context)
    constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs)
    constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
    constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes)
    constructor() : super()
    constructor(contentView: View?) : super(contentView)
    constructor(width: Int, height: Int) : super(width, height)
    constructor(contentView: View?, width: Int, height: Int) : super(contentView, width, height)
    constructor(contentView: View?, width: Int, height: Int, focusable: Boolean) : super(contentView, width, height, focusable)

    override fun showAsDropDown(anchor: View) {
        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.M) {
            val rect = Rect()
            anchor.getGlobalVisibleRect(rect)
            val h = anchor.resources.displayMetrics.heightPixels - rect.bottom
            height = h
        }
        super.showAsDropDown(anchor)
    }
}

WechatIMG14.jpeg

然后，我們需要先寫一個類似京東地址選擇的xml己单，因為radioGroup可以方便監(jiān)聽選擇狀態(tài)唉窃，而且可以復用recyclerview，

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">
    <!-- 陰影區(qū) -->
    <View
        android:id="@+id/backgroundView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="@color/black"
        android:alpha="0.5"
        <!-- 這里不是在titleCl而是tabRg是為了控制圓角效果 -->
        app:layout_constraintBottom_toTopOf="@id/tabRg"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <!-- 用來添加背景 -->
    <View
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="@drawable/bg_popupwindow_radius"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@id/titleCl" />
    <!-- 頂部title和取消 -->
    <android.support.constraint.ConstraintLayout
        android:id="@+id/titleCl"
        android:layout_width="0dp"
        android:layout_height="65dp"
        android:layout_marginBottom="10dp"
        app:layout_constraintBottom_toTopOf="@id/tabRg"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent">

        <TextView
            android:id="@+id/titleTv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#333333"
            android:textSize="18dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>

        <ImageView
            android:id="@+id/cancelTv"
            android:layout_width="20dp"
            android:layout_height="20dp"
            android:layout_marginEnd="20dp"
            android:gravity="center"
            android:paddingStart="20dp"
            android:paddingEnd="20dp"
            android:background="@drawable/close_drawable"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

    </android.support.constraint.ConstraintLayout>
    <!-- 選擇器頂部的tab -->
    <RadioGroup
        android:id="@+id/tabRg"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:orientation="horizontal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toTopOf="@id/contentLl"
        app:layout_constraintStart_toStartOf="parent">

        <RadioButton
            android:id="@+id/firstRb"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginStart="20dp"
            android:button="@null"
            android:paddingTop="10dp"
            android:gravity="center_horizontal"
            android:text="請選擇"
            android:maxLines="1"
            android:ellipsize="end"
            android:checked="true"
            android:textColor="#333333"
            android:textSize="13dp"
            tools:checked="true" />

        <RadioButton
            android:id="@+id/secondRb"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginStart="25dp"
            android:button="@null"
            android:maxLines="1"
            android:ellipsize="end"
            android:paddingTop="10dp"
            android:visibility="gone"
            android:gravity="center_horizontal"
            android:text="請選擇"
            android:textColor="#333333"
            android:textSize="13dp" />

        <RadioButton
            android:id="@+id/thridRb"
            android:layout_marginStart="25dp"
            android:layout_width="wrap_content"
            android:button="@null"
            android:maxLines="1"
            android:visibility="gone"
            android:ellipsize="end"
            android:paddingTop="10dp"
            android:gravity="center_horizontal"
            android:text="請選擇"
            android:textColor="#333333"
            android:textSize="13dp"
            android:layout_height="match_parent" />

    </RadioGroup>

    <android.support.constraint.ConstraintLayout
        android:id="@+id/contentLl"
        android:layout_width="0dp"
        android:layout_height="400dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/listItemRv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>

    </android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>

分析一些三級選擇器的參數(shù)纹笼，我們需要一個標題title纹份，一個數(shù)據(jù)源dataSource，一個選擇完成的回調，注意這里的數(shù)據(jù)源可以根據(jù)實際情況進行修改蔓涧，不一定非要傳三個list件已。

class ThirdLevelListPopupWindow(
        private val context: Context,
        private val title: String = "標題",
        private val dataSource: () -> ThirdLevelListDataModel,
        private val commitCallback: (param1: String,param2: Sting,param3: String) -> Unit
) : PopupWindowV24(context) {
    ...
}

分析一下這個三級列表的屬性，首先元暴，因為是三級列表篷扩，所以一定是每一級都依賴上一級的選擇來進行聯(lián)動，所以需要監(jiān)聽每次RecyclerView的點擊位置茉盏。
同時鉴未，我們要根據(jù)點擊的item來設置頂部tab的文字內容，所以需要在數(shù)據(jù)源中取出item中的數(shù)據(jù)鸠姨，默認賦值為-1來表示初始化沒有選擇item的情況铜秆。

    private var firstList: ArrayList<String> = ArrayList()
    private var secondList: ArrayList<String> = ArrayList()
    private var thirdList: ArrayList<String> = ArrayList()

    private var firstIndex = -1
    set(value) {
        field = value
        if (value == -1) {
            firstRb.text = "請選擇"
        } else {
            firstRb.text = firstList[value]
        }
    }

    private var secondIndex = -1
    set(value) {
        field = value
        if (value == -1) {
            secondRb.text = "請選擇"
        } else {
            secondRb.text = secondList[value]
        }
    }


    private var thirdIndex = -1
    set(value) {
        field = value
        if (value == -1) {
            thirdRb.text = "請選擇"
        } else {
            thirdRb.text = thirdList[value]
        }
    }

我們還需要一個標記來判斷當前選中的tab：

private var curTabPosition : Int = 0

接下來我們要對RecyclerView的adapter進行設計，我們需要傳入一個List數(shù)據(jù)源讶迁，一個選中位置的標記连茧，還有一個選擇item的點擊閉包。
由于我們復用了同一個recyclerView巍糯，所以當我們選擇不同tab的時候梅屉，要更改對應的數(shù)據(jù)源，需要在外部更改數(shù)據(jù)源鳞贷、點擊事件、和選擇item的位置虐唠，所以我們用閉包來在外部控制數(shù)據(jù)搀愧。

class ThirdLevelListPopupWindowAdapter(
        private val dataSource : () -> List<String>,
        val isSelectedBlock: (Int) -> Boolean,
        val block: (Int) -> Unit)
: RecyclerView.Adapter<AddressListPopupWindowAdapter.ViewHolder>() {
    ...
}

其中item的點擊事件在onBindViewHolder()中進行設置

        holder.itemView.setOnClickListener{
            block.invoke(position)
        }

在ThirdLevelListPopupWindow中初始化這個adapter：

adapter = ThirdLevelListPopupWindowAdapter({
            when (curTabPosition) {
                0 -> firstList
                1 -> secondList
                else -> thirdList
            }
        }, {
            when (curTabPosition) {
                0 -> it == firstIndex
                1 -> it == secondIndex
                else -> it == thirdIndex
            }
        },{
            when (curTabPosition) {
                0 -> setFirstTab(it)
                1 -> setSceondTab(it)
                else -> setThirdTab(it)
            }
        })

將adapter綁定到RecyclerView之后，為三個tab設置點擊事件疆偿，

         firstRb.setOnClickListener {
            firstRb.isChecked = true
            curTabPosition = 0
            adapter.notifyDataSetChanged()
        }
        secondRb.setOnClickListener {
            secondRb.isChecked = true
            curTabPosition = 1
            adapter.notifyDataSetChanged()
        }
        thirdRb.setOnClickListener {
            thirdRb.isChecked = true
            curTabPosition = 2
            adapter.notifyDataSetChanged()
        }

每一級的RecyclerView的點擊事件

    private fun setFirstTab(position: Int) {
        firstIndex = position
        firstRb.text = firstList[position]
        secondRb.visibility = View.VISIBLE
        secondRb.text = "請選擇"
        secondIndex = -1
        secondRb.isChecked= true
        secondList.clear()
        initData(secondList)    //這里方法根據(jù)自己的實際情況去實現(xiàn)即可
        thirdIndex = -1
        thirdRb.visibility = View.GONE
        curTabPosition = 1
        adapter.notifyDataSetChanged()
    }

    private fun setSecondTab(position: Int) {
        curTabPosition = 2
        thirdIndex = -1
        thirdList.clear()
        initData(thirdList)
        thirdRb.visibility = View.VISIBLE
        thirdRb.isChecked = true
        thirdRb.text = "請選擇"
        secondIndex = position
        adapter.notifyDataSetChanged()
    }

    private fun setSecondTab(position: Int) {
        thridIndex = position
        commitCallback.invoke(firstList[firstIndex], secondList[secondIndex], thirdList[thirdIndex])
        dismiss()
    }