Android_ExpandableListView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <ImageView
        android:id="@+id/item_iv"
        android:layout_width="90dp"
        android:layout_height="90dp"
        android:src="@drawable/sor"
        android:focusable="false"
        android:layout_margin="20dp"></ImageView>
    <TextView
        android:id="@+id/item_tv"
        android:layout_width="match_parent"
        android:layout_height="90dp"
        android:text="item1"
        android:textSize="25dp"
        android:gravity="center_vertical"
        android:layout_margin="20dp"
        android:focusable="false"></TextView>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:id="@+id/tv_group"
        android:layout_width="match_parent"
        android:layout_height="90dp"
        android:text="数学"
        android:paddingLeft="50dp"
        android:gravity="center_vertical"
        android:background="@drawable/btn_nocornor"
        android:textSize="25dp"
        ></TextView>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".ExpandableView.ExpandableViewActivity">
    <ExpandableListView
        android:id="@+id/expad_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:childDivider="#212"></ExpandableListView>
</RelativeLayout>

package com.example.myapplication5.ExpandableView;

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

import com.example.myapplication5.R;

import java.security.acl.Group;
import java.util.ArrayList;

public class MyBaseExpandableListAdapter extends BaseExpandableListAdapter {
    private ArrayList<String> gData;
    private ArrayList<ArrayList<String[]>> iData;
    private Context mContext;
    public MyBaseExpandableListAdapter(ArrayList<String> gData, ArrayList<ArrayList<String[]>> iData,Context mContext){
        this.gData=gData;
        this.iData=iData;
        this.mContext=mContext;
    }
    @Override
    public int getGroupCount() {
        return gData.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return iData.get(groupPosition).size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return gData.get(groupPosition);
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return iData.get(groupPosition).get(childPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        ViewHolderGroup viewHolderGroup;
        if (convertView==null){
            convertView= LayoutInflater.from(mContext).inflate(R.layout.layout_item_expanda_group,parent,false);
            viewHolderGroup=new ViewHolderGroup();
            viewHolderGroup.tv_g_name=convertView.findViewById(R.id.tv_group);
            convertView.setTag(viewHolderGroup);
        }else {
            viewHolderGroup= (ViewHolderGroup) convertView.getTag();
        }
        viewHolderGroup.tv_g_name.setText(gData.get(groupPosition));
        return convertView;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
       ViewHolderItem viewHolderItem;
       if (convertView==null){
           convertView=LayoutInflater.from(mContext).inflate(R.layout.layout_item_expanda_item,parent,false);
           viewHolderItem=new ViewHolderItem();
           viewHolderItem.tv_it_name=convertView.findViewById(R.id.item_tv);
           viewHolderItem.iv_it_head=convertView.findViewById(R.id.item_iv);
           convertView.setTag(viewHolderItem);
       }else {
           viewHolderItem= (ViewHolderItem) convertView.getTag();
       }
       String[] strings=iData.get(groupPosition).get(childPosition);
       viewHolderItem.tv_it_name.setText(strings[0]);
        viewHolderItem.iv_it_head.setImageResource(Integer.parseInt(strings[1]));


        return convertView;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }
    private static class ViewHolderGroup{
        private TextView tv_g_name;
    }
    private static class ViewHolderItem{
        private TextView tv_it_name;
        private ImageView iv_it_head;
    }
}

package com.example.myapplication5.ExpandableView;

import androidx.appcompat.app.AppCompatActivity;

import android.content.ClipData;
import android.content.Context;
import android.os.Bundle;
import android.widget.ExpandableListView;

import com.example.myapplication5.R;

import java.security.acl.Group;
import java.util.ArrayList;

public class ExpandableViewActivity extends AppCompatActivity {
    private ArrayList<String> gData=null;
    private ArrayList<ArrayList<String[]>> iData=null;
    private ArrayList<String[]> ldata=null;
    private Context mcontext;
    private ExpandableListView expandableListView;
    private MyBaseExpandableListAdapter myAdapter = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_expandable_view);
        expandableListView=findViewById(R.id.expad_view);
        gData=new ArrayList<String>();
        iData=new ArrayList<ArrayList<String[]>>();
        ldata=new ArrayList<String[]>();
        gData.add("康师傅");
        gData.add("今麦郎");
        gData.add("上品");
        ldata.add(new String[]{"红烧牛肉面",(""+R.drawable.sor)});
        ldata.add(new String[]{"老坛酸菜牛肉面",(""+R.drawable.sor)});
        iData.add(ldata);
        ldata=new ArrayList<>();
        ldata.add(new String[]{"西红柿鸡蛋打卤面",(""+R.drawable.sor)});
        ldata.add(new String[]{"酸豆角牛肉面",(""+R.drawable.sor)});
        iData.add(ldata);
        ldata=new ArrayList<>();
        ldata.add(new String[]{"香辣牛肉面",""+R.drawable.sor});
        iData.add(ldata);
        myAdapter=new MyBaseExpandableListAdapter(gData,iData,getApplicationContext());
        expandableListView.setAdapter(myAdapter);
    }
}