ExpandableListView array lists won't stay in the order I put them

Question

I'm making use of the ExpandableListView and I have a few lists set in an array lists.
I set them to be in a certain order which is:

company, day of the week, posh vehicles, topgear vehicles

but what ever I do the order reverts to

posh vehicles, company, days of the week, topgear vehicles

Can anybody help me figure out the problem here is the code I'm using for the stringArray?

 public static HashMap<String, List<String>> getData() {

    HashMap<String, List<String>> expandableListDetail = new HashMap<String, List<String>>();

    List<String> listDataHeader = new ArrayList<String>();
    // Adding child data
    listDataHeader.add("Company");
    listDataHeader.add("Please pick a day");
    listDataHeader.add("Posh Vehicles");
    listDataHeader.add("TopGear Vehicles");

    List<String> CompanyName = new ArrayList<>();
    CompanyName.add("Posh limos");
    CompanyName.add("TopGear limos");

    List<String> daysOftheWeek = new ArrayList<>();
    daysOftheWeek.add("Monday");
    daysOftheWeek.add("Tuesday");
    daysOftheWeek.add("Wednesday");
    daysOftheWeek.add("Thursday");
    daysOftheWeek.add("Thursday");
    daysOftheWeek.add("Friday");
    daysOftheWeek.add("Saturday");
    daysOftheWeek.add("Sunday");

    List<String> poshvehicles = new ArrayList<>();
    poshvehicles.add("Posh H2 limo");
    poshvehicles.add("Iveco party bus");
    poshvehicles.add("Merc party bus ");
    poshvehicles.add("Party coach");

    List<String> topGearVehicles = new ArrayList<>();
    topGearVehicles.add("TopGear H2 limo");
    topGearVehicles.add("TopGear party bus");

    expandableListDetail.put(listDataHeader.get(0),CompanyName);
    expandableListDetail.put(listDataHeader.get(1),daysOftheWeek);
    expandableListDetail.put(listDataHeader.get(2),poshvehicles);
    expandableListDetail.put(listDataHeader.get(3),topGearVehicles);

    return expandableListDetail;

Another hint: There is no point in remembering weekday names in your logic. Instead, you should be using Javas date/calendar APIs - they can do that for you. — GhostCat, Nov 01 '16 at 19:19
thanks as always @GhostCat will take a look at the duplicate question — Mark Harrop, Nov 01 '16 at 19:41

ROMANIA_engineer · Accepted Answer · 2016-11-01T19:28:28.543

1

The HashMap doesn't keep the insertion order.

You can use a LinkedHashMap instead (which extends HashMap):

Map<String, List<String>> expandableListDetail = new LinkedHashMap<>();

I also used the interface name on the left side Map and the diamond operator (<>) that works if you have at least Java 7.

edited Nov 01 '16 at 19:28

answered Nov 01 '16 at 19:12

ROMANIA_engineer

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I feel tempted to downvote on answering that obvious "dup" question; but won't as you at least put in that nice detail about using the diamond operator ;-) – GhostCat Nov 01 '16 at 19:18

ExpandableListView array lists won't stay in the order I put them

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