Android Studio 二级树形列表---1

  在做手机app开发的过程中通常数据列表展示都是一级的，通常用的组件也就是 ListView，GridView。但是有的时候会用到二级列列表，或者三级列表。今天我们就介绍一下二级树形列表如何实现：

  今天要用到 ExpandableListView组件来实现可折叠列表功能。

  首先我们先找一下一个小案例，看看菜鸟教程是如何做的。菜鸟教程链接：https://www.runoob.com/w3cnote/android-tutorial-expandablelistview.html

  

 教程的实现结果是：

 看上去使我们想要实现的结果，但是在实际开发中也要考虑实际情况的。所以把它拿来用也要根据自己的业务情况做一下改进。

 首先自定义一个类MyExpandableListAdapter继承基类BaseExpandableListAdapter并实现其所有方法，每个重写方法表示什么意思，已经标注：

package com.example.appview.Common.ThreeTree;

import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;

public class MyExpanableListAdapterHelper extends BaseExpandableListAdapter {

    //组数量
    @Override
    public int getGroupCount() {
        return 0;
    }
    //子View数量
    @Override
    public int getChildrenCount(int groupPosition) {
        return 0;
    }
    //获取组对象
    @Override
    public Object getGroup(int groupPosition) {
        return null;
    }
    //获取子View对象
    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return null;
    }
    // 组View下标
    @Override
    public long getGroupId(int groupPosition) {
        return 0;
    }
    //子View下标
    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return 0;
    }
    //不知道做什么用
    @Override
    public boolean hasStableIds() {
        return false;
    }
    //取得用于显示给定分组的视图. 这个方法仅返回分组的视图对象
    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        return null;
    }
    //取得显示给定分组给定子位置的数据用的视图
    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        return null;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return false;
    }
}

我们就以机楼和采集器的关系做一个二级树形列表，一个机楼可能安装多个采集器：

定义一个机楼，采集模型：

package com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model;

import android.provider.ContactsContract;

import java.util.Date;
import java.util.List;

public class JiLouModel {
    private int JiLouId;//机楼ID
    private String JiLouName;//机楼名字
    private String Path;//图片路径
    private Date AddTime;//添加时间
    private List<CaiJiModel> CaiJiList;
 public void setJiLouId(int jiLouId) {
        JiLouId = jiLouId;
    }

    public int getJiLouId() {
        return JiLouId;
    }

    public void setJiLouName(String jiLouName) {
        JiLouName = jiLouName;
    }

    public String getJiLouName() {
        return JiLouName;
    }


    public void setPath(String path) {
        Path = path;
    }

    public String getPath() {
        return Path;
    }

    public void setAddTime(Date addTime) {
        AddTime = addTime;
    }

    public Date getAddTime() {
        return AddTime;
    }

    public void setCaiJiList(List<CaiJiModel> caiJiList) {
        CaiJiList = caiJiList;
    }

    public List<CaiJiModel> getCaiJiList() {
        return CaiJiList;
    }

    static class CaiJiModel {
        private int CaiJiId;//采集器
        private String CaiJiNumber;//采集器编号
        private String Path;//图片路径
        private Date AddTime;//添加时间
      public void setCaiJiId(int caiJiId) {
            CaiJiId = caiJiId;
        }

        public int getCaiJiId() {
            return CaiJiId;
        }

        public void setCaiJiNumber(String caiJiNumber) {
            CaiJiNumber = caiJiNumber;
        }

        public String getCaiJiNumber() {
            return CaiJiNumber;
        }

        public void setAddTime(Date addTime) { AddTime = addTime; }

        public Date getAddTime() { return AddTime; }

        public void setPath(String path) {
            Path = path;
        }

        public String getPath() {
            return Path;
        }
    }
}

对MyExpanableListAdapterHelper稍作修改：

package com.example.appview.Common.ThreeTree;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

import com.example.appview.R;
import com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model.JiLou;
import com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model.JiLouModel;

import java.util.List;

public class MyExpanableListAdapterHelper extends BaseExpandableListAdapter {
    private Context context;
    public List<JiLou> JilouModellist;
    LayoutInflater layoutInflater;
    public MyExpanableListAdapterHelper(Context context, List<JiLou> JilouModellist){
        this.JilouModellist=JilouModellist;
        layoutInflater = LayoutInflater.from(context);
    }
    //组数量
    @Override
    public int getGroupCount() {
        return JilouModellist.size();
    }
    //子View数量
    @Override
    public int getChildrenCount(int groupPosition) {
        return JilouModellist.get(groupPosition).getCaiJiList().size();
    }
    //获取组对象
    @Override
    public Object getGroup(int groupPosition) {
        return JilouModellist.get(groupPosition);
    }
    //获取子View对象
    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return JilouModellist.get(groupPosition).getCaiJiList().get(childPosition);
    }
    // 组View下标
    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }
    //子View下标
    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }
    //不知道做什么用
    @Override
    public boolean hasStableIds() {
        return false;
    }
    //取得用于显示给定分组的视图. 这个方法仅返回分组的视图对象
    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        convertView=  layoutInflater.inflate(R.layout.preject_item_addcaiji_onetree, null);
        TextView textView = convertView.findViewById(R.id.preject_item_caijiqi_onetree);
        textView.setText(JilouModellist.get(groupPosition).getJiLouName());
        return convertView;
    }
    //取得显示给定分组给定子位置的数据用的视图
    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        convertView=  layoutInflater.inflate(R.layout.preject_item_addcaiji_twotree, null);
        convertView.setPadding(50,5,0,5);
        TextView textView = convertView.findViewById(R.id.preject_item_dianbiao);
        textView.setText(JilouModellist.get(groupPosition).getCaiJiList().get(childPosition).getCaiJiNumber());
        return convertView;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return false;
    }
}

preject_item_addcaiji_onetree 布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/white"
    android:orientation="horizontal">

 <LinearLayout
     android:layout_width="match_parent"
     android:layout_height="50dp"
     android:descendantFocusability="blocksDescendants"
     android:background="@drawable/mainpage_gridview"
     android:elevation="10dp"
     android:orientation="horizontal">
  <LinearLayout
      android:id="@+id/preject_item_layout_onetree"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1">
   <ImageView

       android:layout_width="40dp"
       android:layout_marginLeft="10dp"

       android:layout_gravity="center"
       android:background="@mipmap/preject_item_caijiqi"
       android:layout_height="40dp"/>
  </LinearLayout>

  <TextView
      android:id="@+id/preject_item_caijiqi_onetree"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1"
      android:gravity="center"
      android:text="采集器编号"
      android:textColor="@color/black"/>

  <TextView
      android:id="@+id/preject_item_addtime_onetree"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="2"
      android:text="2021-08-12 11:19:00"
      android:textColor="@color/black"
      android:gravity="center"
      />
  <LinearLayout
      android:layout_width="0dp"
      android:id="@+id/preject_item_imagecaiji_onetree"
      android:layout_height="match_parent"
      android:focusable="false"
      android:clickable="true"
      android:layout_weight="1">

   <ImageView
       android:id="@+id/preject_item_caijiqi"
       android:layout_width="30dp"
       android:layout_height="30dp"
       android:background="@mipmap/preject_item_caozuo"
       android:layout_gravity="center"
       android:layout_marginLeft="20dp"/>
  </LinearLayout>

 </LinearLayout>
</LinearLayout>

preject_item_addcaiji_twotree布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/white"
    android:orientation="horizontal">

 <LinearLayout
     android:layout_width="match_parent"
     android:layout_height="50dp"
     android:background="@drawable/mainpage_gridview"
     android:elevation="10dp"
     android:descendantFocusability="blocksDescendants"
     android:orientation="horizontal">
  <LinearLayout
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1">
   <ImageView
       android:id="@+id/preject_item_jztype"
       android:layout_width="40dp"
       android:layout_marginLeft="10dp"
       android:layout_gravity="center"
       android:background="@mipmap/preject_item_dianbiao"
       android:layout_height="40dp"/>
  </LinearLayout>

  <TextView
      android:id="@+id/preject_item_dianbiao"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1"
      android:gravity="center"
      android:text="电表表号"
      android:textColor="@color/black"/>
  <TextView
      android:id="@+id/preject_item_dianbiao_address"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1"
      android:text="通信地址"
      android:textColor="@color/black"
      android:gravity="center"
      />
  <TextView
      android:id="@+id/preject_item_addtime_twotree"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="2"
      android:text="2021-08-12 11:19:00"
      android:textColor="@color/black"
      android:gravity="center"/>
  <LinearLayout
      android:layout_width="0dp"
      android:id="@+id/preject_item_layoutcaozuo_twotree"
      android:focusable="false"
      android:clickable="true"
      android:layout_height="match_parent"
      android:layout_weight="1">

   <ImageView
       android:id="@+id/preject_item_dianbiao_caozuo"
       android:layout_width="30dp"
       android:layout_height="30dp"
       android:layout_gravity="center"

       android:background="@mipmap/preject_item_caozuo"
       android:layout_marginLeft="20dp"
       />
  </LinearLayout>

 </LinearLayout>

</LinearLayout>

新建一个Demo  Activity：

package com.example.appview;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.example.appview.Common.ThreeTree.MyExpanableListAdapterHelper;
import com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model.JiLou;
import com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model.JiLouModel;
import com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model.ThreeTreeModel;
import com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model.Tree.ExpandableListViewInterface;
import com.example.appview.mian_page.Frament.Preject_Tance_Frament.ItemA_Model.Tree.ParentAdapterHelper;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class Demo extends AppCompatActivity {
    private ExpandableListView expandableListView;
    List<JiLou> jiLouModels=new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_demo);
       expandableListView = findViewById(R.id.expandable_listView);
        initData();
        MyExpanableListAdapterHelper adapterHelper=new MyExpanableListAdapterHelper(Demo.this,jiLouModels);
        //ParentAdapterHelper<One,Two,Three> adapterHelper=new ParentAdapterHelper(this,threeTreeModels,new One(),new Two(),new Three());
        expandableListView .setAdapter(adapterHelper);

    }
    //创造数据
    private void initData() {
        for (int m=0;m<4;m++) {
            JiLou jiLou=new JiLou();
            jiLou.setJiLouId(m);
            jiLou.setJiLouName("机楼"+m);
            jiLou.setPath("");
            jiLou.setAddTime(new Date(System.currentTimeMillis()));

            List<JiLou.CaiJi> caiJiModels=new ArrayList<>();
            for (int j = 0; j < 6; j++)
            {
                JiLou.CaiJi caiJiModel=new JiLou.CaiJi();
                caiJiModel.setCaiJiId(j);
                caiJiModel.setCaiJiNumber(String.valueOf(j));
                caiJiModel.setPath("");
                caiJiModel.setAddTime(new Date(System.currentTimeMillis()));
                caiJiModels.add(caiJiModel);
            }
            jiLou.setCaiJiList(caiJiModels);
            jiLouModels.add(jiLou);
        }
    }

}

Demo布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    tools:context=".Demo">
    <ExpandableListView
        android:id="@+id/expandable_listView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</LinearLayout>

效果图：

19:56:52

这样一个简单能够自由对接的数据的二级树形列表实现了，但是这样远远不够，如果经常使用的话，就要考虑能不能封装成一个通用的类。这样以后使用起来就方便多了。后续我会把这个二级树形封装一下。以后还会介绍一下三级树形的实现以及三级树形菜单的封装。

这里放一个三级树形列表实现的效果图，后续会介绍一下如何实现：