Android ExpandableListView with Checkbox, Controlling checked state

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

Answer 1

ExpandableListView with multiselect. Tested on API 4.3 and 4.0.3 This code also correctly handles changing screen orientation. Blocking groups made ​​to work properly with the selected elements through SparseBooleanArray.

I hope this sample code will help :)

Activity

ExpandableListView list;
ArrayList cat = new ArrayList();
private YourAdapter mAdapter;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout);
    list = (ExpandableListView)findViewById(R.id.list);
    mAdapter = new YourAdapter(this, list, cat);
    if(savedInstanceState == null)
        //collect your data
    list.setAdapter(mAdapter);
    list.setItemsCanFocus(false);
    list.setChoiceMode(AbsListView.CHOICE_MODE_MULTIPLE);
    list.setOnChildClickListener(this);
    list.setOnGroupClickListener(this);
}

public boolean onGroupClick(ExpandableListView parent, View v,
            int groupPosition, long id) {
        return cat.get(groupPosition).selected;
}

public boolean onChildClick(ExpandableListView parent, View v,
            int groupPosition, int childPosition, long id) {
        YouCat cat = new YouCat();
        YouSubCat subcat = new YouSubCat();
        subcat = cat.get(groupPosition).sub.get(childPosition);
        subcat.selected = !cat.get(groupPosition).sub.get(childPosition).selected;
        cat.get(groupPosition).sub.set(childPosition, subcat);

        boolean isGroupHasSelected = false;
        for(int i = 0; i < cat.get(groupPosition).sub.size() && !isGroupHasSelected; i ++){
            isGroupHasSelected = cat.get(groupPosition).sub.get(i).selected;
        }
        cat = cat.get(groupPosition);
        cat.selected = isGroupHasSelected;
        cat.set(groupPosition, cat);
        //mAdapter.notifyDataSetChanged();

        int position = parent.getFlatListPosition(ExpandableListView.getPackedPositionForChild(groupPosition, childPosition));
        parent.setItemChecked(position, subcat.selected);

        return true;
}

 public void onRestoreInstanceState(Bundle savedInstanceState) {
     super.onRestoreInstanceState(savedInstanceState);
     //restore data 
     cat = (ArrayList) savedInstanceState.getSerializable("cat");
     Type selType = new TypeToken() {}.getType();
     SparseBooleanArray checked = new Gson().fromJson(savedInstanceState.getString("sel"), selType);
     //set new data to adapter and refresh
     mAdapter.refreshList(cat);
 }


 public void onSaveInstanceState(Bundle savedInstanceState) {
     super.onSaveInstanceState(savedInstanceState);
     //save data and selection from list to bundle
     savedInstanceState.putSerializable("cat", cat);
     savedInstanceState.putString("sel", new Gson().toJson(list.getCheckedItemPositions()).toString());
 }

Adapter

public class YouAdapter extends BaseExpandableListAdapter{

    private Context context;
    private List mGroupCollection;
    private ExpandableListView mExpandableListView;

    public YouAdapter(Context context, ExpandableListView pExpandableListView,
            List pGroupCollection) {
        this.context = context;
        this.mGroupCollection = pGroupCollection;
        this.mExpandableListView = pExpandableListView;
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return mGroupCollection.get(groupPosition).sub.get(childPosition).name;
    }

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

    class ChildHolder {
    CheckBox checkBox;
    TextView name, desc;
   }

    @Override
    public View getChildView(int groupPosition, int childPosition,
            boolean isLastChild, View convertView, ViewGroup parent) {
        ChildHolder childHolder;
        if( convertView == null ){
            convertView = LayoutInflater.from(context).inflate(R.layout.childrow, null);
            childHolder = new ChildHolder();
            childHolder.checkBox = (CheckBox) convertView.findViewById(R.id.myCheckBox);
            childHolder.name=(TextView)convertView.findViewById(R.id.textView1);
            childHolder.desc=(TextView)convertView.findViewById(R.id.textView2);
            convertView.setTag(childHolder);
       }else{
            childHolder = (ChildHolder) convertView.getTag(); 
       }
        childHolder.name.setText(mGroupCollection.get(groupPosition).sub.get(childPosition).name);
        childHolder.desc.setText(mGroupCollection.get(groupPosition).sub.get(childPosition).desc);
        childHolder.checkBox.setChecked(mGroupCollection.get(groupPosition).sub.get(childPosition).selected);

        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return mGroupCollection.get(groupPosition).sub.size();
    }

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

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

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

    class GroupHolder {
      TextView title;
   }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {
        GroupHolder groupHolder;
       if( convertView == null ){
            convertView = LayoutInflater.from(context).inflate(R.layout.grouplayout,null);
            groupHolder = new GroupHolder();
            groupHolder.title = (TextView)convertView.findViewById( R.id.text1 );
            convertView.setTag(groupHolder);
       }else{
            groupHolder = (GroupHolder) convertView.getTag(); 
       }
       groupHolder.title.setText(mGroupCollection.get(groupPosition).name);
       return convertView;
    }

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

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

    public void refreshList(List collection){
        mGroupCollection = collection;
        notifyDataSetChanged();
        for(int g = 0; g < mGroupCollection.size(); g ++){
            if(mGroupCollection.get(g).selected)
                mExpandableListView.expandGroup(g);
            else
                mExpandableListView.collapseGroup(g);
        }
    }

}

YouCat class

public class YouCat implements Serializable {
        private static final long serialVersionUID = 2070450081971040619L;
        public String name = null;
        public boolean selected = false;
        public ArrayList sub = new ArrayList();
}

YouSubCat class

public class YouSubCat implements Serializable {
    private static final long serialVersionUID = -1487507723105914936L;
    public String name = null, desc = null;
    public boolean selected = false;
}

Child row layout

Group layout

Get selected child items

final SparseBooleanArray checkedItems = list.getCheckedItemPositions();
for (int i = 0; i < checkedItems.size(); i++) {
  if(checkedItems.valueAt(i))
    data = ((String)list.getItemAtPosition(checkedItems.keyAt(i)));
}