ExpandableListView 자동으로 열어보여주기

ExpandableListView elv = (ExpandableListView)findViewById(R.id.elvMarks);

MyexpandableListAdapter ad = new MyexpandableListAdapter();

elv.setAdapter(ad);

for(int i=0;i<ad.getGroupCount();i++)

elv.expandGroup(i);

public boolean expandGroup (int groupPos)

True if the group was expanded, false otherwise (if the group was already expanded, this will return false)