Welcome to Android ExpandableListView Example Tutorial. In this tutorial we’ll implement an ExpandableListView which is used to group list data by categories. It’s sort of menu and submenus in a Android ListView.
Android ExpandableListView is a view that shows items in a vertically scrolling two-level list. It differs from a ListView by allowing two levels which are groups that can be easily expanded and collapsed by touching to view and their respective children items. ExpandableListViewAdapter in android loads the data into the items associated with this view. Following are some important methods that are used by this class :
state_last
will be setstate_empty
will be set. If the group is expanded, the state state_expanded
will be setThe notable interfaces that are implemented by this class are given below :
This project consists of three classes.
The activity_main.xml layout consists of an ExpandableListView in a RelativeLayout as shown below : activity_main.xml
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
xmlns:tools="https://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity">
<ExpandableListView
android:id="@+id/expandableListView"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:indicatorLeft="?android:attr/expandableListPreferredItemIndicatorLeft"
android:divider="@android:color/darker_gray"
android:dividerHeight="0.5dp" />
</RelativeLayout>
The android:indicatorLeft is the left bound for an items indicator. Note : We cannot use the value wrap_content for the android:layout_height attribute of the ExpandableListView
in XML unless the parent’s size is strictly specified The layout of the group header of each individual list is given below : list_group.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:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
android:textColor="@android:color/black"
android:paddingTop="10dp"
android:paddingBottom="10dp" />
</LinearLayout>
The layout row of the child items is given below : list_item.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="wrap_content">
<TextView
android:id="@+id/expandedListItem"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft"
android:paddingTop="10dp"
android:paddingBottom="10dp" />
</LinearLayout>
The ExpandableListDataPump
class is defined as below:
package com.journaldev.expandablelistview;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class ExpandableListDataPump {
public static HashMap<String, List<String>> getData() {
HashMap<String, List<String>> expandableListDetail = new HashMap<String, List<String>>();
List<String> cricket = new ArrayList<String>();
cricket.add("India");
cricket.add("Pakistan");
cricket.add("Australia");
cricket.add("England");
cricket.add("South Africa");
List<String> football = new ArrayList<String>();
football.add("Brazil");
football.add("Spain");
football.add("Germany");
football.add("Netherlands");
football.add("Italy");
List<String> basketball = new ArrayList<String>();
basketball.add("United States");
basketball.add("Spain");
basketball.add("Argentina");
basketball.add("France");
basketball.add("Russia");
expandableListDetail.put("CRICKET TEAMS", cricket);
expandableListDetail.put("FOOTBALL TEAMS", football);
expandableListDetail.put("BASKETBALL TEAMS", basketball);
return expandableListDetail;
}
}
In the above code the expandableListDetail
object is used to map the group header strings to their respective children using an ArrayList of Strings. CustomExpandableListAdapter.java
package com.journaldev.expandablelistview;
import java.util.HashMap;
import java.util.List;
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;
public class CustomExpandableListAdapter extends BaseExpandableListAdapter {
private Context context;
private List<String> expandableListTitle;
private HashMap<String, List<String>> expandableListDetail;
public 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 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 = layoutInflater.inflate(R.layout.list_item, null);
}
TextView expandedListTextView = (TextView) convertView
.findViewById(R.id.expandedListItem);
expandedListTextView.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 = layoutInflater.inflate(R.layout.list_group, null);
}
TextView listTitleTextView = (TextView) 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;
}
}
This class extends BaseExpandableListAdapter and it overrides the methods in the base class to provide the view for the ExpandableListView. getView() fills in the data into the item’s view with the given index. MainActivity.java
package com.journaldev.expandablelistview;
import android.support.v7.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 = (ExpandableListView) findViewById(R.id.expandableListView);
expandableListDetail = ExpandableListDataPump.getData();
expandableListTitle = new ArrayList<String>(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;
}
});
}
}
In the above code we’ve implemented all the interfaces that were discussed before. For the sake of simplicity, we’ll only display a Toast with the name of the item or the state of the group for every click. But these can be easily modified to perform any other operations. Below is our app with android expandable list view in action. Note: ExpandableListViews are scrollable by default. This brings an end to Android ExpandableListView tutorial. You can download the final Android ExpandableListView Project from the below link.
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how can i add + and - button for adding new child item and removing exiting child item
- mg
can you please help me with a bottom loading inside expandable list
- sharookh
how can i get child view on click of expandable group
- Deepak Kumar
Can this be adapted to show in a Simple Dialog Builder model?
- George Russell
sir Thanks for this tutorial. i have one doubt, how can i create dynamic expandable listview. the groups and childrens data from json data(webservices). in my code two arrays getting “category and items” dynamicaly view category and corresponding items ,how can done?
- sari
Hi, is it possible to shift the position of items? Like according to your example I want to change the team position as first to display basketball then wants to display cricket after I want to display football Team. if we can do this then how could we do this? can you please explain?
- Jyoti
This was very helpful and easy to understand. Thank you.
- Alif Hasnain
This is really great job. THANKS
- Junaidu Tanko
Hi , how can i populate Expendable listView using Json from Volley and mysql (I have 2 tables Article and comments ), otherly how can i use dynamic data thank you
- Ram M
Hello Team, Thank you for the detailed information. A very nice example for a beginner.
- Maruti Nedre