How to keep ExpandableListView in expanded status?

Question

I use

SimpleExpandableListAdapter

in my

ExpandableListActivity

When user click the group row, the children list is expanded and show, when user click each child item in the expanded list, user will be navigated to the next second_Activity. Currently, when user click the back button to go back from second_Activity to the ExpandableListActivity, the expandable list is initialized as un-expanded, I would like the expandable list keep in expanded status, so that user know previously which item he has selected. How to do that? Which method from ExpandableListActivity should be override?

PS: I know I should put getExpandableListView().expandGroup(groupPosition); somewhere, but where? I tried to put this code in onGroupClick() and onChildClick(), but this does not help.

score 65 · Answer 1 · answered Feb 23 '12 at 05:41

65

For always expanded groups, I extend SimpleExpandableListAdapter and set the group to be expanded in the getGroupView method:

@Override
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
    View v = super.getGroupView(groupPosition, isExpanded, convertView, parent);
    ExpandableListView eLV = (ExpandableListView) parent;
    eLV.expandGroup(groupPosition);
    return v;
}

answered Feb 23 '12 at 05:41

straya

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There seems to be a few problems when doing it this way. Apparently (though I haven't checked) the [ListView loses focus after scrolling](http://howrobotswork.wordpress.com/2013/05/26/keep-groups-expanded-in-expandablelistview). In my case though, it was occasionally causing a random NullPointerException during ExpandableListView.getFlatListPosition(), when getting the first child of a group. Manually expanding each group after setting the adapter seemed to solve it. – technicalflaw Oct 31 '13 at 18:03
WARNING: Not sufficient, if you dynamically add views in an empty group: you need to add the `parent.expandGroup` in **getChildView** either – cyrilchampier Apr 14 '14 at 08:15
Haven't experienced the issues, but this is far more simple when you add whole new groups compared expanding everything every time you change something. – Warpzit Jan 23 '15 at 12:19

score 9 · Answer 2 · edited Apr 05 '12 at 14:05

9

I was browsing around trying to find a solution to my own ExpandableListView problem. Anyway, add my 2 cents to the answer provided by adstro.

The concept is simple: First call the getGroupCount() function of the ExpandableList Adapter to find the number of groups Then, loop through the groups and call the expandGroup(int GroupPos) function of the ExpandableList View to expand each group.

The above codes should be put inside onCreate() and also the onResume() to cater for both the first creation and the return to the activity subsequently after creation.

edited Apr 05 '12 at 14:05

Andro Selva

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answered Jun 27 '11 at 10:33

Yam

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7

7

Putting it only onResume should be enough, since anything that goes through onCreate will also go through onResume. – xaethos Aug 22 '12 at 01:56

adstro · Answer 3 · 2010-11-02T19:53:36.227

3

I did something similar, except I keep all the groups expanded all the time. To accomplish this, I got a handle to the listView via ExpandableListActivity.getExpandableListView() and use ExpandableListView.expandGroup (int groupPos) to expand the groups.

For your scenario, you could keep track of which group(s) is/are expanded and once the activity to loaded again, re-expand them.

Hope this helps.

One other thing...I put this code in OnCreate().

edited Nov 02 '10 at 19:53

answered Nov 02 '10 at 19:47

adstro

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adstro,could you post the code,i am unable to understand it properly – ProgramME Jun 15 '11 at 14:18
2

@ProgramME he meant tmpListView.expandGroup(0); considering you wish to expand the group at position 0 if you wish to expand all the items do it in a for loop. – Jayshil Dave Oct 27 '11 at 11:02

score 2 · Answer 4 · edited Sep 25 '14 at 07:58

 @Override
 View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup     parent) {
     View v = super.getGroupView(groupPosition, isExpanded, convertView, parent);
     ExpandableListView eLV = (ExpandableListView) parent;
     eLV.expandGroup(groupPosition);
     return v;
}

after that

     expListView.setOnChildClickListener(new OnChildClickListener() {

     @Override
     public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
         Toast.makeText(getApplicationContext(),listDataHeader.get(groupPosition)
             + " : " 
             + listDataChild.get(listDataHeader.get(groupPosition)).get(childPosition),Toast.LENGTH_SHORT).show();
         return false;
     }
    });

in onResume...

Worked for me. No problem with scrolling.

Damian Petla · Answer 5 · 2013-09-13T10:00:27.823

1

Solution provided by straya is not good for Android 2.3.3. Your ExpandableListView will lost focus and click events will stop working after list is scrolled.

edited Sep 13 '13 at 10:00

answered Sep 13 '13 at 07:56

Damian Petla

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5
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Do you have any explanations for this behavior? I thought it was a bug – glodos Sep 29 '13 at 13:46

score 0 · Answer 6 · answered May 20 '16 at 11:11

I have done this way:

ExpandableAdpater adapter=new ExpandableAdapter(context);
expandableListView.setAdapter(adapter);

for (int i = 0; i < listResponse.size(); i++) {
                                expandableListView.expandGroup(i);
                            }

How to keep ExpandableListView in expanded status?

6 Answers6

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