JSONArray tasks = obj.getJSONArray("activities");

Map<Integer, List<Task>> childs = Parser.parseActivitiesIntoGroups(tasks.toString());

final TodoAdapter adapter = new TodoAdapter(getActivity(), groups, childs);
list.setAdapter(adapter);
list.setOnChildClickListener(new OnChildClickListener() {
    @Override
    public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
        Adapter a = parent.getAdapter();
        Task task = (Task) ((TodoAdapter) parent.getExpandableListAdapter()).getChild(groupPosition, childPosition);

        Intent intent = new Intent(getActivity(), TodoTaskEditActivity.class);
        intent.putExtra(INTENT_TASK, task);
        startActivity(intent);

        return true;
    }
});

public void onCreate(Bundle savedInstanceState) {
    Intent intent = getIntent();
    if (intent != null) {
        Task task = intent.getParcelableExtra(TodoFragment.INTENT_TASK);
        //This is fine and task has the proper values
        if (task != null) {
            //it enters this way
            date.setText(format.format(task.ActivityDate));
            ...  //set a lot of edittexts, etc
        } else {
            ...  //set some default values in edittexts, etc
        }
    }

    //at this point task is already null
    date.setOnClickListener(new OnClickListener() {
        ...
    }