Question

Friends,

I am trying to write a application which use checkbox in ExpandableListView, I got a problem here which is maintaining checkbox state of the application, I got the example from here , my problem is maintaining checked state of the checkboxes, whenever I check one of the checkboxes and Expand the List, the checkboxes do not have the checked state where they supposed to have. I have try to maintain by adding ArrayList to store the position of the store and reload the position in getChildView() but still not achieve what I want to do. here is my code

public class ElistCBox extends ExpandableListActivity {

    private static final String LOG_TAG = "ElistCBox";
    ArrayList<String > chkState = new ArrayList<String>();
    static final String colors[] = {"grey","blue","yellow","red"};
    static final String shades[][] ={ { "lightgrey","#D3D3D3","dimgray","#696969", "sgi >gray 92","#EAEAEA"},
        { "dodgerblue 2","#1C86EE","steelblue >2","#5CACEE","powderblue","#B0E0E6"},
        { "yellow 1","#FFFF00", "gold 1","#FFD700","darkgoldenrod 1"," #FFB90F" },
        {"indianred 1","#FF6A6A", "firebrick 1","#FF3030", "maroon","#800000" } };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle icicle)
    {
        super.onCreate(icicle);
        setContentView(R.layout.main); 
        SimpleExpandableListAdapter expListAdapter = new SimpleExpandableListAdapter( 
            this,
            createGroupList(),
            R.layout.group_row, new String[] { "colorName" },
            new int[] { R.id.childname }, createChildList(),
            R.layout.child_row,
            new String[] { "shadeName", "rgb" },
            new int[] { R.id.childname, R.id.rgb }
        ) { 
            @Override public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent)
            {
                final View v = super.getChildView(groupPosition, childPosition, isLastChild, convertView, parent);

                final CheckBox chkColor = (CheckBox)v.findViewById(R.id.check1);

                if(chkState.contains(groupPosition+","+childPosition)){
                    chkColor.setChecked(true);
                }else{
                    chkColor.setChecked(false);
                }
                chkColor.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.e("Checkbox Onclick Listener", Integer.toString(groupPosition) + " - " + Integer.toString(childPosition));
                    }
                });
                chkColor.setOnCheckedChangeListener(new OnCheckedChangeListener() {
                    @Override
                    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                        Log.e("Checkbox check change Listener", Integer.toString(groupPosition) + " - " + Integer.toString(childPosition));
                        if(chkColor.isChecked()){
                            chkState.add(groupPosition+","+childPosition);
                        } else {
                            chkState.remove(groupPosition+","+childPosition); 
                        }
                    }
                });
                return super.getChildView(groupPosition, childPosition, isLastChild, convertView, parent);
            }
        };
        setListAdapter( expListAdapter );
    }

    public void onContentChanged  () {
        super.onContentChanged();
        Log.e( LOG_TAG, "onContentChanged" );
    }

    public boolean onChildClick(
            ExpandableListView parent, 
            View v, 
            int groupPosition,
            int childPosition,
            long id) {
        Log.e( LOG_TAG, "onChildClick: "+childPosition );
        CheckBox cb = (CheckBox)v.findViewById( R.id.check1 );
        if( cb != null )
        cb.toggle();
        return false;
    }

    public void  onGroupExpand  (int groupPosition) {
        Log.e( LOG_TAG,"onGroupExpand: "+groupPosition );
    }

    private List createGroupList() {
        ArrayList result = new ArrayList();
        for( int i = 0 ; i < colors.length ; ++i ) {
            HashMap m = new HashMap();
            m.put( "colorName",colors[i] );
            result.add( m );
        }
        return (List)result; 
    }

    private List createChildList() {
        ArrayList result = new ArrayList();
        for( int i = 0 ; i < shades.length ; ++i ) {
            ArrayList secList = new ArrayList();
            for( int n = 0 ; n < shades[i].length; n += 2 ) {
                HashMap child = new HashMap();
                child.put( "shadeName", shades[i][n] );
                child.put( "rgb", shades[i][n+1] ); secList.add( child );
            }
            result.add( secList );
        } 
        return result;
    }
}

Answer 1

this is my answer to the this issue, u need to keep a check state for individual child and check on it when the the child is clicked. after some research, this is due to android’s view lifecycle causing the view to refresh thus not keeping the state.

public class MyExpandableListAdapter extends BaseExpandableListAdapter {
//Variables
// Sample data set.  children[i] contains the children (String[]) for groups[i].
private String[] groups = { "People Names", "Dog Names", "Cat Names", "Fish Names" }; //headers
private String[][] children = {
        { "Arnold", "Barry", "Chuck", "David" },
        { "Ace", "Bandit", "Cha-Cha", "Deuce" },
        { "Fluffy", "Snuggles" },
        { "Goldy", "Bubbles" }
};
private String[] group_vaues = {"PN", "DN", "CN", "FN"};
private String[][] children_values = {
        { "Ar", "Ba", "Ch", "Da" },
        { "Ace", "Ban", "Cha", "Deu" },
        { "Flu", "Snu" },
        { "Gol", "Bub" }
};
ArrayList<ArrayList<Integer>> check_states = new ArrayList<ArrayList<Integer>>();

private Context context;

//Constructors
public MyExpandableListAdapter() {

}

public MyExpandableListAdapter(Context c) {
    this.context = c;
}

//Set Methods
public void setGroupsAndValues(String[] g, String[] v) {
    this.groups = g;
    this.group_vaues = v;
}

public void setChildrenAndValues(String[][] c, String[][] v) {
    this.children = c;
    this.children_values = v;
    //initialize the states to all 0;
    for(int i = 0; i < c.length; i++) {
        ArrayList<Integer> tmp = new ArrayList<Integer>();
        for(int j = 0; j < c[i].length; j++) {
            tmp.add(0);
        }
        check_states.add(tmp);
    }
}

//Get Methods
public Object getChild(int groupPosition, int childPosition) {
    return children[groupPosition][childPosition];
}

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

public int getChildrenCount(int groupPosition) {
    return children[groupPosition].length;
}

public View getChildView(int groupPosition, int childPosition, boolean isLastChild,
        View convertView, ViewGroup parent) {
    View grid;


   LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   grid = inflater.inflate(R.layout.specialty_list_item, parent, false);

   final int grpPos = groupPosition;
   final int childPos = childPosition;

    TextView header = (TextView)grid.findViewById(R.id.title);
    header.setText(getChild(groupPosition, childPosition).toString());
    final View tick = grid.findViewById(R.id.image);
    if(check_states.get(grpPos).get(childPos) == 1)
        tick.setVisibility(View.VISIBLE);
    else
        tick.setVisibility(View.GONE);

    grid.setOnClickListener(new OnClickListener(){
        @Override
        public void onClick(View v) {
            check_states.get(grpPos).set(childPos, 1);
            tick.setVisibility(View.VISIBLE);
        }
    });

    return grid;
}

public Object getGroup(int groupPosition) {
    return groups[groupPosition];
}

public int getGroupCount() {
    return groups.length;
}

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

public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
        ViewGroup parent) {
    View grid;

    if(convertView==null){
       grid = new View(context);
       LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
       grid = inflater.inflate(R.layout.specialty_header, parent, false);
    }else{
       grid = (View)convertView;
    }

    TextView header = (TextView)grid.findViewById(R.id.specialty_header);
    header.setText(getGroup(groupPosition).toString());


    return grid;
}

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

public boolean hasStableIds() {
    return true;
}

}