Question

I have an expandablelistview with a checkbox by group and a checkbox by child.
when a group is checked/unchecked all the childs are checked/unchecked.I got no problem to with keep the state of this checkbox, but i want to force the expandableListView to redraw to show all the childs checkbox checked or unchecked immediately.
I search for hours and didn’t find solution.
Is anyone can explain me our to solve this problem, i ll be really glad.

here is the code where i manage the checkbox changes in my expandableListAdapter :

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

    GroupViewHolder gholder;
    final TypeVehicule type=(TypeVehicule) getGroup(groupPosition);
    if (convertView==null)
    {
        gholder=new GroupViewHolder();
        convertView = inflater.inflate(R.layout.listevehicule_type,null);
        gholder.textViewGroup=(TextView)convertView.findViewById(R.id.LV_textType);
        gholder.checkType=(CheckBox)convertView.findViewById(R.id.LV_CheckType);
        gholder.checkType.setTag(groupPosition);        
        gholder.imgType=(ImageView)convertView.findViewById(R.id.LV_ImageType);
        convertView.setTag(gholder);
    }
    else
    {
        gholder = (GroupViewHolder)convertView.getTag();
    }
    gholder.textViewGroup.setText(type.getType());
        if (type.getColor()==-1)
        { 
            int color;
            Random rnd = new Random(); 
            color = Color.argb(255, rnd.nextInt(256), rnd.nextInt(256), rnd.nextInt(256));
            type.setColor(color);       
        }   
        gholder.imgType.setBackgroundColor(type.getColor());
        gholder.checkType.setChecked(type.isIschecked());

        gholder.checkType.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) 
            {                   
                type.setIschecked(((CheckBox) v).isChecked());

                    for (Vehicule _v : type.getListeVehicules())
                    {
                        _v.setIschecked(type.isIschecked());

                    }
            }       

        });

        gholder.checkType.setChecked(type.isIschecked());
      //
    return convertView;
}

and the code of the onCreate :

protected void onCreate(Bundle savedInstanceState) 
{
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(net.ornicar.ornimobile.R.layout.listevehicule);
    listView_Vehic = (ExpandableListView)findViewById(R.id.ListeVehicules);     
    // ici pour l'instant on rempli en dur en attendant l'implementation de la couche metier..      
    for (int i=1; i<10;i++)
    {
        TypeVehicule type = new TypeVehicule("Type " + i);

        ArrayList<Vehicule> oListVeh = new ArrayList<Vehicule>();

        for (int j=0;j<10;j++)
        {
            oListVeh.add(new Vehicule(type, "Veh N°"+j+"-"+i));
        }
        type.setListVehicule(oListVeh);
        oListType .add(type);           
    }
    ListeVehiculesAdapter adapter = new ListeVehiculesAdapter(this, oListType,true);
    listView_Vehic.setAdapter(adapter);
    this.registerForContextMenu(listView_Vehic);
    listView_Vehic.setOnChildClickListener(new  OnChildClickListener() {

        @Override
        public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { 
            Toast.makeText(getApplicationContext(), oListType.get(groupPosition).getListeVehicules().get(childPosition).getNom()+" Clicked!!", 4000).show();    
            return true;
        }
    });

}

Answer 1

To force any (Expandable)ListView to redraw, you can call the notifyDataSetChanged on the Adapter used by the view. This will force a redraw on whatever is visible on screen. This means that your adapter must extend BaseAdapter or BaseExpandableListAdapter.