安卓开发级联显示菜单-省市区显示举例

安卓开发级联显示菜单-省市区显示举例

问题背景

安卓日常开发过程，经常会有需要级联显示的场景，比如省市区显示等，或者各种组织结构级联显示，本文将介绍安卓开发过程实现级联显示的一种方案。
实现效果如下：

问题分析

思路分析：
考虑将要是的省、市、区设计成一种字典迭代结构，数据结构如下：

/**
 * 组织实体类
 */
class Organization(var name: String, var subList: MutableList?)

这种数据结构，当前页面即可显示当前组织的子列表内容，比较方便。
话不多少，直接上代码：
（1）数据结构实体类

/**
 * 组织实体类
 */
class Organization(var name: String, var subList: MutableList?)

（2）页面显示activity，代码如下：

package com.baorant.kotlinorganization

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import androidx.recyclerview.widget.LinearLayoutManager
import com.baorant.kotlinorganization.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {
    private lateinit var activityMainBinding: ActivityMainBinding
    private lateinit var topListAdapter : TopAdapter
    private val topList = mutableListOf()

    private val organizationList = mutableListOf()
    private lateinit var subOrgListAdapter : OrganizationAdapter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        activityMainBinding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(activityMainBinding.root)

        initView()

        initData()
    }

    private fun initData() {
        // 模拟省市区级联数据
        val organization111 = Organization("南关区", null);
        val organization112 = Organization("朝阳区", null);
        val organization113 = Organization("绿园区", null);
        val organization110List = ArrayList()
        organization110List.add(organization111)
        organization110List.add(organization112)
        organization110List.add(organization113)

        val organization121 = Organization("丰满区", null);
        val organization122 = Organization("龙潭区", null);
        val organization123 = Organization("蛟河区", null);
        val organization120List = ArrayList()
        organization120List.add(organization121)
        organization120List.add(organization122)
        organization120List.add(organization123)

        val organization11 = Organization("长春市", organization110List)
        var organization12 = Organization("吉林市", organization120List)

        val organization11List = ArrayList()
        organization11List.add(organization11)
        organization11List.add(organization12)

        val organization1 = Organization("吉林省", organization11List);
        organizationList.add(organization1)
        subOrgListAdapter.notifyDataSetChanged()

    }

    private fun initView() {
        // 显示层级的横向列表
        val layoutManager = LinearLayoutManager(this)
        layoutManager.orientation = LinearLayoutManager.HORIZONTAL
        activityMainBinding.recyclerView.layoutManager = layoutManager
        topListAdapter = TopAdapter(topList)
        topListAdapter.setOnItemClickListener(object: OnItemClickListener{
            override fun onItemClick(view: View, position: Int) {
                val organization = topList[position]
                organizationList.clear()
                organization.subList?.let { organizationList.addAll(it) }
                subOrgListAdapter.notifyDataSetChanged()

                val temList = mutableListOf()
                for (index in topList.indices) {
                    if (index <= position) {
                        temList.add(topList[index])
                    }
                }
                topList.clear()
                topList.addAll(temList)
                topListAdapter.notifyDataSetChanged()
            }
        })
        activityMainBinding.recyclerView.adapter = topListAdapter

        // 展示当前层级子项的纵向列表
        val subLayoutManager = LinearLayoutManager(this)
        activityMainBinding.subOrgList.layoutManager = subLayoutManager

        subOrgListAdapter = OrganizationAdapter(organizationList)
        subOrgListAdapter.setOnItemClickListener(object : OnItemClickListener {
            override fun onItemClick(view: View, position: Int) {
                val organization = organizationList[position]
                if (organization.subList == null) {
                    return
                }
                organizationList.clear()
                organization.subList?.let { organizationList.addAll(it) }
                subOrgListAdapter.notifyDataSetChanged()

                topList.add(organization)
                topListAdapter.notifyDataSetChanged()
            }
        })
        activityMainBinding.subOrgList.adapter = subOrgListAdapter
    }
}

（3）activity对应布局layout文件，代码如下：

（4）纵向子列表对应adapter，代码如下：

package com.baorant.kotlinorganization

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView

/**
 * 纵向子列表对应adapter
 */
class OrganizationAdapter(var organizationList:List) : RecyclerView.Adapter() {
    private lateinit var onItemClickListener: OnItemClickListener

    //在内部类里面获取到item里面的组件
    inner class ViewHolder(view:View):RecyclerView.ViewHolder(view){
        var newName:TextView=view.findViewById(R.id.name)
    }

    //重写的第一个方法，用来给制定加载那个类型的Recycler布局
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.list_item,parent,false)
        val viewHolder = ViewHolder(view)
        //单机事件
        viewHolder.itemView.setOnClickListener {
            val position = viewHolder.adapterPosition
            onItemClickListener.onItemClick(viewHolder.itemView, position)
        }

        return viewHolder
    }

    fun setOnItemClickListener(listener: OnItemClickListener) {
        this.onItemClickListener = listener
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val organization = organizationList[position]

        holder.newName.text = organization.name
    }

    override fun getItemCount(): Int {
        return organizationList.size
    }
}

（5）上方横向列表对应adapter，代码如下：

package com.baorant.kotlinorganization

import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView

/**
 * 上方横向列表对应adapter
 */
class TopAdapter(var organizationList:List) : RecyclerView.Adapter() {
    private lateinit var onItemClickListener: OnItemClickListener

    //在内部类里面获取到item里面的组件
    inner class ViewHolder(view:View):RecyclerView.ViewHolder(view){
        var newName:TextView=view.findViewById(R.id.name)
    }

    //重写的第一个方法，用来给制定加载那个类型的Recycler布局
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        Log.d("baorant", "onCreateViewHolder begin")
        val view = LayoutInflater.from(parent.context).inflate(R.layout.top_list_item,parent,false)
        val viewHolder = ViewHolder(view)
        // 点击事件
        viewHolder.itemView.setOnClickListener {
            val position = viewHolder.adapterPosition
            onItemClickListener.onItemClick(viewHolder.itemView, position)
        }

        return viewHolder
    }

    fun setOnItemClickListener(listener: OnItemClickListener) {
        this.onItemClickListener = listener
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        Log.d("baorant", "onBindViewHolder begin")
        val organization = organizationList[position]

        holder.newName.text = organization.name
    }

    override fun getItemCount(): Int {
        Log.d("baorant", "getItemCount begin")
        return organizationList.size
    }
}

（6）自定义接口，代码如下：

/**
 * 自定义接口，适配recyclerview点击事件adapter
 */
interface OnItemClickListener {
    fun onItemClick(view: View, position: Int)
}

问题总结

本文介绍了安卓开发过程实现级联显示的一种方案，有兴趣的同学可以进一步深入研究。