<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:l" />

<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:l" />

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Sunday 24th of November 06:18:07am

Expandable Listener android app Source

Activity_main.xml

=====================

<?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:orientation="vertical"

    android:background="#f4f4f4"

    tools:context="com.sam.web.expandablelistview.MainActivity">


    <ExpandableListView

        android:id="@+id/expandableListViewId"

        android:layout_width="match_parent"

        android:layout_height="match_parent"></ExpandableListView>




</LinearLayout>

==========================================================================


group_layout.xml

=================

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

    xmlns:android="http://schemas.android.com/apk/res/android"

    android:padding="8dp"

    android:background="#ffbb00"

    android:layout_width="match_parent"

    android:layout_height="wrap_content">

    

    <TextView

        android:paddingLeft="?android:expandableListPreferredItemPaddingLeft"

        android:textSize="17sp"

        android:id="@+id/headerTextViewId"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />


</LinearLayout>

============================================================================

child_layout.xml

================

<?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="55dp">


    <TextView

        android:paddingLeft="?android:expandableListPreferredChildPaddingLeft"

        android:textSize="17sp"

        android:paddingBottom="5dp"

        android:textColor="#000000"

        android:id="@+id/childTextViewId"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />


</LinearLayout>

===========================================================================

MainActivity.java

===================

package com.sam.web.expandablelistview;


import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

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 {

    private ExpandableListView expandableListView;

    private CustomAdapter customAdapter;

    List<String> listDataHeader;

    HashMap<String,List<String>>listDataChild;


    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);


        prepareListData();


        expandableListView=(ExpandableListView) findViewById(R.id.expandableListViewId);

        customAdapter=new CustomAdapter(this,listDataHeader,listDataChild);

        expandableListView.setAdapter(customAdapter);

        expandableListView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {

            @Override

            public boolean onGroupClick(ExpandableListView parent, View v, int i, long id) {

                String groupName=listDataHeader.get(i);

                Toast.makeText(getApplicationContext(),"group Name :"+groupName,Toast.LENGTH_SHORT).show();

                return false;

            }

        });

        expandableListView.setOnGroupCollapseListener(new ExpandableListView.OnGroupCollapseListener() {

            @Override

            public void onGroupCollapse(int i) {

                String groupName=listDataHeader.get(i);

                Toast.makeText(getApplicationContext(),groupName+"is Collapsed",Toast.LENGTH_SHORT).show();


            }

        });

        expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {

            @Override

            public boolean onChildClick(ExpandableListView parent, View v, int i, int il, long id) {

                String childString=listDataChild.get(listDataHeader.get(i)).get(il);

                Toast.makeText(getApplicationContext(),childString,Toast.LENGTH_SHORT).show();

                return false;

            }

        });


    }


    private void prepareListData() {

        String[] headerString=getResources().getStringArray(R.array.abbreviations_list_header);

        String[] childString=getResources().getStringArray(R.array.abbreviations_list_child);

        listDataHeader=new ArrayList<>();

        listDataChild=new HashMap<>();


        for (int i=0; i<headerString.length; i++){


//            adding header data

            listDataHeader.add(headerString[i]);

            List<String> child=new ArrayList<>();

            child.add(childString[i]);

            listDataChild.put(listDataHeader.get(i),child);

        }

    }

}

======================================================================================================

CustomAdapter.java

====================

package com.sam.web.expandablelistview;


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 java.util.HashMap;

import java.util.List;


/**

 * Created by maudud on 1/22/18.

 */


public class CustomAdapter extends BaseExpandableListAdapter {

    private Context context;

    List<String> listDataHeader;

    HashMap<String,List<String>> listDataChild;


    public CustomAdapter(Context context, List<String> listDataHeader, HashMap<String, List<String>> listDataChild) {

        this.context = context;

        this.listDataHeader = listDataHeader;

        this.listDataChild = listDataChild;

    }


    @Override

    public int getGroupCount() {

        return listDataHeader.size();

    }


    @Override

    public int getChildrenCount(int i) {

        return listDataChild.get(listDataHeader.get(i)).size();

    }


    @Override

    public Object getGroup(int i) {

        return listDataHeader.get(i);

    }


    @Override

    public Object getChild(int i, int i1) {

        return listDataChild.get(listDataHeader.get(i)).get(i1);

    }


    @Override

    public long getGroupId(int i) {

        return i;

    }


    @Override

    public long getChildId(int i, int i1) {

        return i1;

    }


    @Override

    public boolean hasStableIds() {

        return false;

    }


    @Override

    public View getGroupView(int i, boolean b, View view, ViewGroup viewGroup) {

        String headerText=(String) getGroup(i);

        if(view==null){


            LayoutInflater inflater= (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            view=inflater.inflate(R.layout.group_layout,null);

        }

        TextView textView=view.findViewById(R.id.headerTextViewId);

        textView.setText(headerText);

        return view;


    }


    @Override

    public View getChildView(int i, int i1, boolean b, View view, ViewGroup viewGroup) {

        String childText=(String) getChild(i,i1);

        if(view==null){


            LayoutInflater inflater= (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            view=inflater.inflate(R.layout.child_layout,null);

        }

        TextView textView=view.findViewById(R.id.childTextViewId);

        textView.setText(childText);

        return view;

    }


    @Override

    public boolean isChildSelectable(int groupPosition, int childPosition) {

        return true;

    }

}

============================================================================================================================

Strings.xml

=============

<resources>

    <string name="app_name">ExpandableListView</string>

    <string-array name="abbreviations_list_header">


        <item>AAI</item>

        <item>ALu</item>

        <item>ATI</item>

        <item>AVI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

        <item>AAI</item>

    </string-array>

    <string-array name="abbreviations_list_child">


        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>

        <item>Advanced audio coding

        AAC is coding as an audio coding which is able to coding </item>


    </string-array>

</resources>