CheckBox states in ExpandableListView's children

Question

I've read about 30 pages from SO as well as tutorials about tracking check states in lists but info (especially working info) is scarce on doing so in an Expandable ListView.

I've got the children populating with checkboxes but when I check a box on a child from 1 group, random children in other groups also check. I need to stop this. The best info I think I read was to set the checkbox as a separate tag but I don't know how to set multiple tags, when I tried, I got a class mismatch error comparing the checkbox to the convertview.

Has anybody come across a good way to keep track of checkbox states in an expandablelistview's children?

I've made multiple changes so I'm putting in the entire adapter code. Please check first few lines of getGroupView and entire getChildView and help me see what I'm doing wrong.

EDIT: What's happening now is that when I check a box and then expand another group, all checked boxes uncheck:

public class MyExpandableListAdapter extends BaseExpandableListAdapter
    implements OnCheckedChangeListener {

private Context mContext;

private ArrayList<ContactNameItems> mListDataHeader;
private HashMap<String, List<ContactPhoneItems>> mListDataChild;

private boolean[] mGetChecked;
private HashMap<String, boolean[]> mChildCheckStates;

private ArrayList<String> selectedNumbers;

private ChildViewHolder childViewHolder;
private GroupViewHolder groupViewHolder;

private String numberText;

public MyExpandableListAdapter(Context context,
        ArrayList<ContactNameItems> listDataHeader,
        HashMap<String, List<ContactPhoneItems>> listDataChild,
        ArrayList<String> listOfNumbers) {

    mContext = context;
    mListDataHeader = listDataHeader;
    mListDataChild = listDataChild;
    selectedNumbers = listOfNumbers;

    mChildCheckStates = new HashMap<String, boolean[]>();
}

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

@Override
public ContactNameItems getGroup(int groupPosition) {
    return mListDataHeader.get(groupPosition);
}

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

@Override
public View getGroupView(int groupPosition, boolean isExpanded,
        View convertView, ViewGroup parent) {

    String contactName = getGroup(groupPosition).getName();
    Bitmap contactImage = getGroup(groupPosition).getImage();

    mGetChecked = new boolean[getChildrenCount(groupPosition)];
    mChildCheckStates.put(contactName, mGetChecked);

    if (convertView == null) {

        LayoutInflater inflater = (LayoutInflater) mContext
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.contact_name_item, null);

        groupViewHolder = new GroupViewHolder();

        groupViewHolder.mContactName = (TextView) convertView
                .findViewById(R.id.lblListHeader);

        groupViewHolder.mContactImage = (ImageView) convertView
                .findViewById(R.id.ivContactPhoto);

        convertView.setTag(groupViewHolder);
    } else {

        groupViewHolder = (GroupViewHolder) convertView.getTag();
    }

    if (contactImage != null) {
        groupViewHolder.mContactImage.setImageBitmap(contactImage);

    } else {
        groupViewHolder.mContactImage
                .setImageResource(R.drawable.default_contact);
    }

    groupViewHolder.mContactName.setText(contactName);

    return convertView;
}

@Override
public int getChildrenCount(int groupPosition) {
    return mListDataChild.get(mListDataHeader.get(groupPosition).getName())
            .size();
}

@Override
public ContactPhoneItems getChild(int groupPosition, int childPosition) {
    return mListDataChild.get(mListDataHeader.get(groupPosition).getName())
            .get(childPosition);
}

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

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

    final String contactName = getGroup(groupPosition).getName();
    final int mChildPosition = childPosition;

    numberText = getChild(groupPosition, childPosition).getNumber();
    String typeText = getChild(groupPosition, childPosition).getPhoneType();

    mGetChecked = mChildCheckStates.get(contactName);

    if (convertView == null) {

        LayoutInflater inflater = (LayoutInflater) this.mContext
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.contact_detail_item, null);

        childViewHolder = new ChildViewHolder();

        childViewHolder.mPhoneNumber = (TextView) convertView
                .findViewById(R.id.tv_phone_number);

        childViewHolder.mPhoneType = (TextView) convertView
                .findViewById(R.id.tv_phone_type);

        childViewHolder.mCheckBox = (CheckBox) convertView
                .findViewById(R.id.checkBox);

        convertView.setTag(R.layout.contact_detail_item, childViewHolder);

    } else {

        childViewHolder = (ChildViewHolder) convertView
                .getTag(R.layout.contact_detail_item);
    }

    childViewHolder.mPhoneNumber.setText(numberText);
    childViewHolder.mPhoneType.setText(typeText);

    childViewHolder.mCheckBox.setChecked(mGetChecked[mChildPosition]);
    childViewHolder.mCheckBox.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            boolean isChecked = childViewHolder.mCheckBox.isChecked();

            Log.d("Debug", "isChecked = " + String.valueOf(isChecked));

            if (isChecked) {

                selectedNumbers.add(numberText);

            } else {

                selectedNumbers.remove(numberText);
            }

            childViewHolder.mCheckBox.setChecked(isChecked);

            mGetChecked[mChildPosition] = isChecked;
            mChildCheckStates.put(contactName, mGetChecked);
        }
    });

    return convertView;
}

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

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

public ArrayList<String> getSelectedNumbers() {

    return selectedNumbers;

}

public final class GroupViewHolder {

    TextView mContactName;
    ImageView mContactImage;
}

public final class ChildViewHolder {

    TextView mPhoneNumber;
    TextView mPhoneType;
    CheckBox mCheckBox;
}

@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    // TODO Auto-generated method stub
    Log.d("Debug", "onCheckChangedListener : " + String.valueOf(isChecked));
}

}

Answer 1

HERE IS THE WORKING SOLUTION

OK, although there seems to be a lot of suggestions on the internet about checkboxes in expandable listviews, none had worked for me. I was able to get it working with the help of a bunch of people, especially anddev84. Now I'm not going to claim that this is perfect or foolproof. I'm just claiming that it works for me. I've tested on 2 devices and I'm very pleased with it.

So I've taken my working code, dwindled it down to its essential parts and added a bunch of helpful comments so anybody who needs it can you it. Hopefully it works as well for you as it does for me. Enjoy

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

import android.annotation.SuppressLint;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.TextView;

// Eclipse wanted me to use a sparse array instead of my hashmaps, I just suppressed that suggestion
@SuppressLint("UseSparseArrays")
public class MyExpandableListAdapter extends BaseExpandableListAdapter {

    // Define activity context
    private Context mContext;

    /*
     * Here we have a Hashmap containing a String key 
     * (can be Integer or other type but I was testing 
     * with contacts so I used contact name as the key)
    */ 
    private HashMap<String, List<ExpListChildItems>> mListDataChild;

    // ArrayList that is what each key in the above 
    // hashmap points to
    private ArrayList<ExpListGroupItems> mListDataGroup;

    // Hashmap for keeping track of our checkbox check states
    private HashMap<Integer, boolean[]> mChildCheckStates;

    // Our getChildView & getGroupView use the viewholder patter
    // Here are the viewholders defined, the inner classes are
    // at the bottom
    private ChildViewHolder childViewHolder;
    private GroupViewHolder groupViewHolder;

    /*  
     *  For the purpose of this document, I'm only using a single
     *  textview in the group (parent) and child, but you're limited only
     *  by your XML view for each group item :)
    */ 
    private String groupText;
    private String childText

    /*  Here's the constructor we'll use to pass in our calling
     *  activity's context, group items, and child items
    */ 
    public MyExpandableListAdapter(Context context,
            ArrayList<ExpListGroupItems> listDataGroup, HashMap<String, List<ExpListChildItems>> listDataChild) {

        mContext = context;
        mListDataGroup = listDataGroup;
        mListDataChild = listDataChild;

        // Initialize our hashmap containing our check states here
        mChildCheckStates = new HashMap<Integer, boolean[]>();
    }

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

    /*  
     * This defaults to "public object getGroup" if you auto import the methods
     * I always make a point to change it from "object" to whatever item
     * I passed through the constructor
    */ 
    @Override
    public ExpListGroupItems getGroup(int groupPosition) {
        return mListDataGroup.get(groupPosition);
    }

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

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {

        //  I passed a text string into an activity holding a getter/setter
        //  which I passed in through "ExpListGroupItems".
        //  Here is where I call the getter to get that text
        groupText = getGroup(groupPosition).getGroupText();

        if (convertView == null) {

            LayoutInflater inflater = (LayoutInflater) mContext
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.group_item, null);

            // Initialize the GroupViewHolder defined at the bottom of this document
            groupViewHolder = new GroupViewHolder();

            groupViewHolder.mGroupText = (TextView) convertView.findViewById(R.id.groupTextView);

            convertView.setTag(groupViewHolder);
        } else {

            groupViewHolder = (GroupViewHolder) convertView.getTag();
        }

        groupViewHolder.mGroupText.setText(groupText);

        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return mListDataChild.get(mListDataGroup.get(groupPosition).getMyText()).size();
    }

    /*  
     * This defaults to "public object getChild" if you auto import the methods
     * I always make a point to change it from "object" to whatever item
     * I passed through the constructor
    */ 
    @Override
    public ExpListChildItems getChild(int groupPosition, int childPosition) {
        return mListDataChild.get(mListDataGroup.get(groupPosition).getMyText()).get(childPosition);
    }

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

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

        final int mGroupPosition = groupPosition;
        final int mChildPosition = childPosition;

        //  I passed a text string into an activity holding a getter/setter
        //  which I passed in through "ExpListChildItems".
        //  Here is where I call the getter to get that text
        childText = getChild(mGroupPosition, mChildPosition).getChildText();

        if (convertView == null) {

            LayoutInflater inflater = (LayoutInflater) this.mContext
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.child_item, null);

            childViewHolder = new ChildViewHolder();

            childViewHolder.mChildText = (TextView) convertView
                    .findViewById(R.id.childTextView);

            childViewHolder.mCheckBox = (CheckBox) convertView
                    .findViewById(R.id.checkBox);

            convertView.setTag(R.layout.child_item, childViewHolder);

        } else {

            childViewHolder = (ChildViewHolder) convertView
                    .getTag(R.layout.child_item);
        }

        childViewHolder.mChildText.setText(childText);
            /* 
         * You have to set the onCheckChangedListener to null
         * before restoring check states because each call to 
         * "setChecked" is accompanied by a call to the 
         * onCheckChangedListener
        */ 
        childViewHolder.mCheckBox.setOnCheckedChangeListener(null);

        if (mChildCheckStates.containsKey(mGroupPosition)) {
            /*
             * if the hashmap mChildCheckStates<Integer, Boolean[]> contains
             * the value of the parent view (group) of this child (aka, the key),
             * then retrive the boolean array getChecked[]
            */
            boolean getChecked[] = mChildCheckStates.get(mGroupPosition);

            // set the check state of this position's checkbox based on the 
            // boolean value of getChecked[position]
            childViewHolder.mCheckBox.setChecked(getChecked[mChildPosition]);

        } else {

            /*
            * if the hashmap mChildCheckStates<Integer, Boolean[]> does not
            * contain the value of the parent view (group) of this child (aka, the key),
            * (aka, the key), then initialize getChecked[] as a new boolean array
            *  and set it's size to the total number of children associated with 
            *  the parent group
            */
            boolean getChecked[] = new boolean[getChildrenCount(mGroupPosition)];

            // add getChecked[] to the mChildCheckStates hashmap using mGroupPosition as the key
            mChildCheckStates.put(mGroupPosition, getChecked);

            // set the check state of this position's checkbox based on the 
            // boolean value of getChecked[position]
            childViewHolder.mCheckBox.setChecked(false);
        }

        childViewHolder.mCheckBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {

                    @Override
                    public void onCheckedChanged(CompoundButton buttonView,
                            boolean isChecked) {

                        if (isChecked) {

                                boolean getChecked[] = mChildCheckStates.get(mGroupPosition);
                                getChecked[mChildPosition] = isChecked;
                                mChildCheckStates.put(mGroupPosition, getChecked);

                        } else {

                                boolean getChecked[] = mChildCheckStates.get(mGroupPosition);
                                getChecked[mChildPosition] = isChecked;
                                mChildCheckStates.put(mGroupPosition, getChecked);
                        }
                    }
                });

        return convertView;
    }

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

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

    public final class GroupViewHolder {

        TextView mGroupText;
    }

    public final class ChildViewHolder {

        TextView mChildText;
        CheckBox mCheckBox;
    }
}