ExpandableLists in Android, I want to allow only one parent list to expand at a time

Question

I want to make only one item in the parent list expand at a time, my code for the onCreate is currently the following. (It works as I want, But the method to allow only one parent open at a time doesnt work)

public void onCreate(Bundle savedInstanceState) {
        try{
             super.onCreate(savedInstanceState);
             setContentView(R.layout.main);

        final SimpleExpandableListAdapter expListAdapter =
            new SimpleExpandableListAdapter(
                        //FOR LEVEL 1 SCREEN
                    this,
                    createGroupList(),              // METHOD TO CREATE PARENTLIST Creating group List.
                    R.layout.group_row,             // REF TO XML FILENAME.         
                    new String[] { "Group Item" },  // STRING ARRAY HOLDING ONE KEY THAT REF'S ALL PARENT LIST ITEMS.
                    new int[] { R.id.row_name },    // REF TO I.D. OF PARENT XML. ID of each group item.-Data under the key goes into this TextView.                    
                    createChildList(),              // METHOD TO CREATE CHILD LST. childData describes second-level entries.
                    R.layout.child_row,             // XMLFILE NAME FOR CHILD LIST.Layout for sub-level entries(second level).
                    new String[] {"Sub Item"},      // KEY FOR CHILD ITEMS IN HASHMAP. Keys in childData maps to display.
                    new int[] { R.id.grp_child}     // XML ID FOR TEXTVIEW. Data under the keys above go into these TextViews.
                );
            setListAdapter( expListAdapter );       // setting the adapter in the list.

        //**THIS IS WHAT I DONT KNOW HOW TO CODE:**


            list = (ExpandableListView) findViewById(R.id.row_name);
            list.setAdapter( expListAdapter);
            list.setGroupIndicator(null);


            list.setOnGroupExpandListener(new OnGroupExpandListener() {

                public void onGroupExpand(int groupPosition) {
                    int len = expListAdapter.getGroupCount();
                    for (int i = 0; i < len; i++) {
                        if (i != groupPosition) {
                            list.collapseGroup(i);
                        }
                    }
                }
            });

        }catch(Exception e){

            System.out.println("Errrr +++ " + e.getMessage());
        }
    }

I understand the above code, However, I dont use expandableListViews, Im refferncing my program to my .xml files with the layouts of the expandablelist. And so I dont know how to apply the above to my program...

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
 <ExpandableListView android:id="@+id/list"
               android:layout_width="fill_parent" 
               android:layout_height="fill_parent"
               android:background="@drawable/bkg"/>

     <TextView android:id="@+id/android:empty"
               android:layout_width="fill_parent" 
               android:layout_height="fill_parent"
               android:text="No items"/>
</LinearLayout>

The method that I dont know how to apply is the following:

                    list = (ExpandableListView) findViewById(R.id.row_name);
            list.setAdapter( expListAdapter);
            list.setGroupIndicator(null);

            list.setOnGroupExpandListener(new OnGroupExpandListener() {
                    public void onGroupExpand(int groupPosition) {
                    int len = expListAdapter.getGroupCount();
                    for (int i = 0; i < len; i++) {
                        if (i != groupPosition) {
                            list.collapseGroup(i);
                        }
                    }
                }
            });

1) how do I refference the 'list' to my expandablelist activity?

list is defined in the class as private ExpandableListView list;

I do not have any errors right now, But the method does not work.

Any help is greatly appreciated!

Abysmal

Is there no way I can bump this to the top of the listings? – Abysmal

you can find the solution in the following link:- #4315277 – Saprolite

Answer 1

The problem was solved by creating a public explist variable called list, and then referencing it to the adapter in view with the following call.

list = getExpandableListView(); 

The expand method before was crashing the app because of this. After refferencing the list.collapsegroup in, it worked fine.

public void onGroupExpand(int groupPosition) { 
                    System.out.println("GROUP LISTENER WORKS?");
                    if(adptr=="expListAdapter"){
                        int len = expListAdapter.getGroupCount();
                        //System.out.println(len);
                        for (int i = 0; i < len; i++) {
                            if (i != groupPosition) {
                            list.collapseGroup(i);
                            }
                        }

                    }
                    else if(adptr=="expListAdapter2"){
                        int len = expListAdapter2.getGroupCount();
                        for (int i = 0; i < len; i++) {
                            if (i != groupPosition) {
                            list.collapseGroup(i);
                            }
                        }
                        //System.out.println(len);
                    }
                    else if(adptr=="expListAdapter3"){
                        int len = expListAdapter3.getGroupCount();
                        for (int i = 0; i < len; i++) {
                            if (i != groupPosition) {
                            list.collapseGroup(i);
                            }
                        }

                    }
            }

Abysmal

Answer 2

// Declare variable 
private static int prev = -1;
// and OnGroupExpandListener implement


 mExpandableList.setOnGroupExpandListener(new OnGroupExpandListener() {

            @Override
            public void onGroupExpand(int groupPosition) {

                if(prev!=-1)
                {

                    mExpandableList.collapseGroup(prev);    

                }
                prev=groupPosition;
            }
        });

---

Updating with updated solution

mExpandableList.setOnGroupExpandListener(new OnGroupExpandListener() {
    // Keep track of previous expanded parent
    int previousGroup = -1;

    @Override
    public void onGroupExpand(int groupPosition) {
        // Collapse previous parent if expanded.
        if ((previousGroup != -1) && (groupPosition != previousGroup)) {
            mExpandableList.collapseGroup(previousGroup);
        }
        previousGroup = groupPosition;
    }
});

Soddy

Change the check "prev!=-1" to "prev!=-1 && prev!=groupPosition", or you can't expand a group twice in sequence. – Quartan

Or you can add a OnGroupCollapseListener and set prev = -1. – Lubberly

Answer 3

Easiest approach

You can implement ExpandableListView.OnGroupExpandListener, in where you run collapseGroup() for all list groups except the one being clicked. This will do what you want.

 expandableList.setOnGroupExpandListener(new OnGroupExpandListener() {
        int previousGroup = -1;

        @Override
        public void onGroupExpand(int groupPosition) {
            if(groupPosition != previousGroup)
                expandableList.collapseGroup(previousGroup);
            previousGroup = groupPosition;
        }
    });

Ocher

Answer 4

I believe a straight forward solution would be to implement one Adapter to handle any of the events you are interested in.

public class MyExpandableListAdapter extends SimpleExpandableListAdapter {

  public Activity mActivity;

  public MyExpandableListAdapter([ARGS USED IN QUESTION], Activity activity) {super([ARGS USED IN QUESTIONS]); mActivity = activity; }

  // then just override the method
  public void onGroupExpanded(int groupPosition) {
    int len = super.getGroupCount();
    ExpandableListView list = (ExpandableListView) mActivity.findViewById(R.id.list);
    for (int i = 0; i < len; i++) {
        if (i != groupPosition) {
            list.collapseGroup(i);
        }
    }
  }
}

By separating the list adapter into another class you will not clutter the Activity code with one-off listener implementations. Instead, in each Activity simply instantiate the adapter and set it on the list

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // No try catch needed
    MyExpandableListAdapter mAdapter = new MyExpandableListAdapter([ARGS SHOWN IN QUESTION], MainActivity.this);

    ExpandableListView epView = (ExpandableListView) findViewById(R.id.list);
    epView.setAdapter(mAdapter);

    return true;
}

Greasy

I would advise against this approach, as it limits the reusability of the adapter and leads to unnecessary tight coupling between the Adapter and the Activity and the Layout. I would instead propose a solution based on listeners (like Itam's answer) – Daigle

Answer 5

Iram Bukhari's answer is working fine. but i have did once change:

private static int prev = -1;
// and OnGroupExpandListener implement


 mExpandableList.setOnGroupExpandListener(new OnGroupExpandListener() {

            @Override
            public void onGroupExpand(int groupPosition) {

                if(prev!=-1 && prev!=groupPosition )
                {

                    mExpandableList.collapseGroup(prev);    

                }
                prev=groupPosition;
            }
        });

I have added prev!=groupPosition as extra condition. Because if

item 1 has clicked(opened) 
item 1 has clicked(closed) 
item 1 has clicked(Not opening. because prev has same position so the item is opened and collapsed immediatly ) 

After Adding the condition

item 1 has clicked(opened) 
item 1 has clicked(closed) 
item 1 has clicked(opened) 

Indigotin

Answer 6

    @Override
    public void onGroupExpanded(int groupPosition) {
        super.onGroupExpanded(groupPosition);
        int len = getGroupCount();

        for (int i = 0; i < len; i++) {
            if (i != groupPosition) {
               expListView.collapseGroup(i);
            }
        }
    }

Magically

Answer 7

Modified the answer from Iram: So you can reopen the same Group

// Listview Group expanded listener
    expListView.setOnGroupExpandListener(new OnGroupExpandListener() {

        @Override
        public void onGroupExpand(int groupPosition) {
            if (prevouriousExpandedGroupNumber != -1 && prevouriousExpandedGroupNumber != groupPosition) {
                expListView.collapseGroup(prevouriousExpandedGroupNumber);
            }
            prevouriousExpandedGroupNumber = groupPosition;
        }
    });

Brute

Answer 8

Its Working See Screen Shots

package com.keshav.myexpandablelistviewexampleworkinginactivity;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ExpandableListView;
import android.widget.ExpandableListView.OnChildClickListener;
import android.widget.ExpandableListView.OnGroupClickListener;
import android.widget.ExpandableListView.OnGroupCollapseListener;
import android.widget.ExpandableListView.OnGroupExpandListener;
import android.widget.Toast;

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

public class MainActivity extends Activity {

    ExpandableListAdapter listAdapter;
    ExpandableListView expListView;
    List<String> listDataHeader;
    HashMap<String, List<String>> listDataChild;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // tODO get the listview
        expListView = (ExpandableListView) findViewById(R.id.lvExp);

        // TODO preparing list data
        prepareListData();

        listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);

        // setting list adapter
        expListView.setAdapter(listAdapter);

        // Listview Group click listener
        expListView.setOnGroupClickListener(new OnGroupClickListener() {

            @Override
            public boolean onGroupClick(ExpandableListView parent, View v,
                                        int groupPosition, long id) {
                Toast.makeText(getApplicationContext(),
                        "Group Clicked " + listDataHeader.get(groupPosition),
                        Toast.LENGTH_SHORT).show();
                return false;
            }

        });

        // Listview Group expanded listener
        expListView.setOnGroupExpandListener(new OnGroupExpandListener() {

            // TODO Colapse Here Using this... in android
            int previousGroup = -1;
            boolean flag = false;

            @Override
            public void onGroupExpand(int groupPosition) {

                Log.e("keshav", "onGroupClick is -> " + groupPosition);

                Toast.makeText(getApplicationContext(),
                        listDataHeader.get(groupPosition) + " Expanded",
                        Toast.LENGTH_SHORT).show();

                if (groupPosition != previousGroup && flag) {
                    expListView.collapseGroup(previousGroup);
                }
                previousGroup = groupPosition;

                flag = true;

            }
        });


        // Listview Group collasped listener
        expListView.setOnGroupCollapseListener(new OnGroupCollapseListener() {

            @Override
            public void onGroupCollapse(int groupPosition) {
                Toast.makeText(getApplicationContext(),
                        listDataHeader.get(groupPosition) + " Collapsed",
                        Toast.LENGTH_SHORT).show();

            }
        });


        // Todo Listview on child click listener
        expListView.setOnChildClickListener(new OnChildClickListener() {

            @Override
            public boolean onChildClick(ExpandableListView parent, View v,
                                        int groupPosition, int childPosition, long id) {
                // TODO Auto-generated method stub
                Toast.makeText(
                        getApplicationContext(),
                        listDataHeader.get(groupPosition)
                                + " : "
                                + listDataChild.get(
                                listDataHeader.get(groupPosition)).get(
                                childPosition), Toast.LENGTH_SHORT)
                        .show();
                return false;
            }
        });
    }

    /*
     * Preparing the list data
     */
    private void prepareListData() {
        listDataHeader = new ArrayList<String>();
        listDataChild = new HashMap<String, List<String>>();

        // Adding child data
        listDataHeader.add("Months");
        listDataHeader.add("Top 250");
        listDataHeader.add("Now Showing");
        listDataHeader.add("Coming Soon..");


        // Adding child data
        List<String> weeks = new ArrayList<String>();
        weeks.add("Sunday");
        weeks.add("Monday");
        weeks.add("Tuesday");
        weeks.add("Wednesday");
        weeks.add("Thursday");
        weeks.add("Friday");
        weeks.add("Saturday");


        // Adding child data
        List<String> top250 = new ArrayList<String>();
        top250.add("Om Shanti Om");
        top250.add("Badshah");
        top250.add("Bahubali Part 1");
        top250.add("Carry on Jatta");
        top250.add("Sholey");
        top250.add("Mard");
        top250.add("Dewwar");


        List<String> nowShowing = new ArrayList<String>();
        nowShowing.add("Bahubali");
        nowShowing.add("Kabali");
        nowShowing.add("Luckky Di Unlukky Story");
        nowShowing.add("Sachin Billions Dream");
        nowShowing.add("Red 2");

        List<String> comingSoon = new ArrayList<String>();
        comingSoon.add("Tubelight ");
        comingSoon.add("Bahubali 3 2018");
        comingSoon.add("Dhoom 4");
        comingSoon.add("Hindi Medium");

        listDataChild.put(listDataHeader.get(0), weeks);
        listDataChild.put(listDataHeader.get(1), top250); // Header, Child data
        listDataChild.put(listDataHeader.get(2), nowShowing);
        listDataChild.put(listDataHeader.get(3), comingSoon);
    }
}


ExpandableListAdapter


package com.keshav.myexpandablelistviewexampleworkinginactivity;

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 ExpandableListAdapter extends BaseExpandableListAdapter {

    private Context _context;
    private List<String> _listDataHeader; // header titles
    // child data in format of header title, child title
    private HashMap<String, List<String>> _listDataChild;

    public ExpandableListAdapter(Context context, List<String> listDataHeader,
            HashMap<String, List<String>> listChildData) {
        this._context = context;
        this._listDataHeader = listDataHeader;
        this._listDataChild = listChildData;
    }

    @Override
    public Object getChild(int groupPosition, int childPosititon) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .get(childPosititon);
    }

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

    @Override
    public View getChildView(int groupPosition, final int childPosition,
            boolean isLastChild, View convertView, ViewGroup parent) {

        final String childText = (String) getChild(groupPosition, childPosition);

        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_item, null);
        }

        TextView txtListChild = (TextView) convertView
                .findViewById(R.id.lblListItem);

        txtListChild.setText(childText);
        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .size();
    }

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

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

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

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {
        String headerTitle = (String) getGroup(groupPosition);
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_group, null);
        }

        TextView lblListHeader = (TextView) convertView
                .findViewById(R.id.lblListHeader);
        lblListHeader.setTypeface(null, Typeface.BOLD);
        lblListHeader.setText(headerTitle);

        return convertView;
    }

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

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

}


activity_mail.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:background="#f4f4f4" >

            <ExpandableListView
                android:id="@+id/lvExp"
                android:layout_height="match_parent"
                android:layout_width="match_parent"
                android:cacheColorHint="#00000000"/>   

</LinearLayout>


list_grou.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="8dp" 
    android:background="#000000">


    <TextView
        android:id="@+id/lblListHeader"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
        android:textSize="17dp"
        android:textColor="#f9f93d" />

</LinearLayout>


list_item.xml

<?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="55dip"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/lblListItem"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textSize="17dip"
        android:paddingTop="5dp"
        android:paddingBottom="5dp"
        android:textColor="#000000"
        android:paddingLeft="?android:attr/expandableListPreferredChildPaddingLeft" />

</LinearLayout>

Korns

<resources> <style name="AppBaseTheme" parent="android:Theme.Light"> </style> <style name="AppTheme" parent="AppBaseTheme"> </style> </resources> – Korns