วิธีสร้าง ListView หลายระดับ (Multilevel/Expandable) ในแอป Android

การสร้าง ExpandableListView (รายการขยายได้) ใน Android

ตัวอย่างนี้สาธิตการสร้าง ExpandableListView แบบหลายระดับ (Group และ Child) เพื่อแสดงข้อมูลนักกีฬาแยกตามประเภทกีฬา

ขั้นตอนที่ 1: สร้างโปรเจกต์ใหม่

ไปที่ File → New Project ใน Android Studio

ขั้นตอนที่ 2: Layout หลัก (activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:tools="https://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:padding="4dp"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <ExpandableListView
        android:id="@+id/expendableList"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:divider="@android:color/background_light"
        android:dividerHeight="0.5dp"/>
</RelativeLayout>

ขั้นตอนที่ 3: โค้ดหลัก (MainActivity.java)

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    ExpandableListView expandableListView;
    ExpandableListAdapter expandableListAdapter;
    List<String> expandableListTitle;
    HashMap<String, List<String>> expandableListDetail;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        expandableListView = findViewById(R.id.expendableList);
        expandableListDetail = ExpandableListData.getData();
        expandableListTitle = new ArrayList<>(expandableListDetail.keySet());
        expandableListAdapter = new CustomExpandableListAdapter(this, expandableListTitle, expandableListDetail);
        expandableListView.setAdapter(expandableListAdapter);

        expandableListView.setOnGroupExpandListener(new ExpandableListView.OnGroupExpandListener() {
            @Override
            public void onGroupExpand(int groupPosition) {
                Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition) + " List Expanded.", Toast.LENGTH_SHORT).show();
            }
        });

        expandableListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {
            @Override
            public void onGroupCollapse(int groupPosition) {
                Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition) + " List Collapsed.", Toast.LENGTH_SHORT).show();
            }
        });

        expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
            @Override
            public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
                Toast.makeText(getApplicationContext(), expandableListTitle.get(groupPosition) + " -> " + expandableListDetail.get(expandableListTitle.get(groupPosition)).get(childPosition), Toast.LENGTH_SHORT).show();
                return false;
            }
        });
    }
}

ขั้นตอนที่ 4: คลาสข้อมูล (ExpandableListData.java)

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

class ExpandableListData {
    static HashMap<String, List<String>> getData() {
        HashMap<String, List<String>> expandableListDetail = new HashMap<>();
        List<String> myFavCricketPlayers = new ArrayList<>();
        myFavCricketPlayers.add("MS.Dhoni");
        myFavCricketPlayers.add("Sehwag");
        myFavCricketPlayers.add("Shane Watson");
        myFavCricketPlayers.add("Ricky Ponting");
        myFavCricketPlayers.add("Shahid Afridi");

        List<String> myFavFootballPlayers = new ArrayList<>();
        myFavFootballPlayers.add("Cristiano Ronaldo");
        myFavFootballPlayers.add("Lionel Messi");
        myFavFootballPlayers.add("Gareth Bale");
        myFavFootballPlayers.add("Neymar JR");
        myFavFootballPlayers.add("David de Gea");

        List<String> myFavTennisPlayers = new ArrayList<>();
        myFavTennisPlayers.add("Roger Federer");
        myFavTennisPlayers.add("Rafael Nadal");
        myFavTennisPlayers.add("Andy Murray");
        myFavTennisPlayers.add("Novak Jokovic");
        myFavTennisPlayers.add("Sania Mirza");

        expandableListDetail.put("CRICKET PLAYERS", myFavCricketPlayers);
        expandableListDetail.put("FOOTBALL PLAYERS", myFavFootballPlayers);
        expandableListDetail.put("TENNIS PLAYERS", myFavTennisPlayers);
        return expandableListDetail;
    }
}

ขั้นตอนที่ 5: Custom Adapter (CustomExpandableListAdapter.java)

package app.com.sample;

import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
import java.util.HashMap;
import java.util.List;
import java.util.Objects;

class CustomExpandableListAdapter extends BaseExpandableListAdapter {
    private Context context;
    private List<String> expandableListTitle;
    private HashMap<String, List<String>> expandableListDetail;

    CustomExpandableListAdapter(Context context, List<String> expandableListTitle, HashMap<String, List<String>> expandableListDetail) {
        this.context = context;
        this.expandableListTitle = expandableListTitle;
        this.expandableListDetail = expandableListDetail;
    }

    @Override
    public Object getChild(int listPosition, int expandedListPosition) {
        return Objects.requireNonNull(this.expandableListDetail.get(this.expandableListTitle.get(listPosition))).get(expandedListPosition);
    }

    @Override
    public long getChildId(int listPosition, int expandedListPosition) { return expandedListPosition; }

    @Override
    public View getChildView(int listPosition, final int expandedListPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        final String expandedListText = (String) getChild(listPosition, expandedListPosition);
        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = Objects.requireNonNull(layoutInflater).inflate(R.layout.list_row, null);
        }
        TextView textView = convertView.findViewById(R.id.listTitle);
        textView.setText(expandedListText);
        return convertView;
    }

    @Override
    public int getChildrenCount(int listPosition) {
        return this.expandableListDetail.get(this.expandableListTitle.get(listPosition)).size();
    }

    @Override
    public Object getGroup(int listPosition) { return this.expandableListTitle.get(listPosition); }

    @Override
    public int getGroupCount() { return this.expandableListTitle.size(); }

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

    @Override
    public View getGroupView(int listPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        String listTitle = (String) getGroup(listPosition);
        if (convertView == null) {
            LayoutInflater layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = Objects.requireNonNull(layoutInflater).inflate(R.layout.list_row, null);
        }
        TextView listTitleTextView = convertView.findViewById(R.id.listTitle);
        listTitleTextView.setTypeface(null, Typeface.BOLD);
        listTitleTextView.setText(listTitle);
        return convertView;
    }

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

    @Override
    public boolean isChildSelectable(int listPosition, int expandedListPosition) { return true; }
}

ขั้นตอนที่ 6: Layout รายการ (list_row.xml)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView android:id="@+id/listTitle"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:textColor="@android:color/black" />
</LinearLayout>

ขั้นตอนที่ 7: AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android" package="app.com.sample">
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

การทดสอบ

รันแอป จะเห็นรายการ 3 กลุ่ม: CRICKET, FOOTBALL, TENNIS กดขยาย/ย่อได้ และกดรายการย่อยจะแสดง Toast