(Android need help) Checkbox automaticly checked like crazy in expandable listview

Question

I created a expandable listview, childview has checkbox, when expand parent view, check on one checkbox, not only that checkbox be checked also there are another checkboxs be checked. I dont know why and how to fix this problem. I upload sourcecode to mediafire.com in this link:

http://www.mediafire.com/?eih80athr56ejg2

This is MainActivity.java

public class MainActivity extends Activity {

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

private void SetListView(){
    ExpandableListView lv=(ExpandableListView)findViewById(R.id.listview);
    ExpAdapter adapter=new ExpAdapter(this);
    lv.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

This is ExpAdapter.java

public class ExpAdapter extends BaseExpandableListAdapter{
Context mContext;
int[][] data= new int[4][20];
public ExpAdapter(Context c){
    mContext=c;
}
@Override
public Object getChild(int arg0, int arg1) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public long getChildId(int arg0, int arg1) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public View getChildView(int groupPosition, int childPosition, boolean arg2, View convertView,
        ViewGroup parent) {
    // TODO Auto-generated method stub
    if(convertView==null){
         LayoutInflater inflater =  (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         convertView = inflater.inflate(R.layout.childview,parent, false);
    }
    TextView tv=(TextView)convertView.findViewById(R.id.txtChild);
    tv.setText("Child Position="+childPosition);
    return convertView;
}

@Override
public int getChildrenCount(int arg0) {
    // TODO Auto-generated method stub
    return data[arg0].length;
}

@Override
public Object getGroup(int arg0) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public int getGroupCount() {
    // TODO Auto-generated method stub
    return data.length;
}

@Override
public long getGroupId(int arg0) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public View getGroupView(int groupPosition, boolean arg1, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    if(convertView==null){
         LayoutInflater inflater =  (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         convertView = inflater.inflate(R.layout.groupview,parent, false);
    }
    TextView tv=(TextView)convertView.findViewById(R.id.txtGroup);
    tv.setText("Group Position="+groupPosition);
    return convertView;
}

@Override
public boolean hasStableIds() {
    // TODO Auto-generated method stub
    return false;
}

@Override
public boolean isChildSelectable(int arg0, int arg1) {
    // TODO Auto-generated method stub
    return false;
}

Answer 1

I have followed http://androidtrainningcenter.blogspot.in/2012/07/android-expandable-listview-simple.html

All we need is to just store your checkbox's checked status. I have added a checkbox in child view's xml design & store its status in NewAdapter., so that when parent view expands we can restore checkbox status.

Modifications done in NewAdapter :

1. Declared a List of type String named as selectedNames.

2. Changed getChildView method implementation as below.

   tempChild = (ArrayList<String>) Childtem.get(groupPosition);
   TextView text = null;
   
   if (convertView == null) {
       convertView = minflater.inflate(R.layout.childrow, null);
   }
   
   text = (TextView) convertView.findViewById(R.id.textView1);
   text.setText(tempChild.get(childPosition));
   
   cb = (CheckBox) convertView.findViewById(R.id.cb_item);
   
   cb.setOnCheckedChangeListener(null);
   
           cb.setChecked(false);
   
   if (selectedNames.size() > 0
           && selectedNames.indexOf(tempChild.get(childPosition)) != -1) {
   
       cb.setChecked(true);
       // Log.d("Present",tempChild.get(childPosition));
   
   } 
   
   cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
       public void onCheckedChanged(CompoundButton buttonView,
               boolean isChecked) {
           if (isChecked) {
   
               int i = selectedNames.indexOf(tempChild.get(childPosition));
   
               if (i == -1) {
                   selectedNames.add(tempChild.get(childPosition));
               }
           } else {
   
               int i = selectedNames.indexOf(tempChild.get(childPosition));
   
               if (i != -1) {
                   selectedNames.remove(i);
               }
   
           }
   
       }
   });
   
   return convertView;