CODEWITHSUNDEEP
javaandroidsortinglistview
Sam Justman
Sam Justman

Reputation: 412

How to sort items in a listview by a value of item?

I have a ListView and I want to sort items by a specific Database value of those items. The value will also be in the item. It will not be a one-time sorting. I mean it will do the sorting every time when the activity is created. I am using an adapter for it.

I've already checked every similar question but I could not find a proper solution.

Is there a way to do it? Thank you very much in advance.

This is the Firebase Database Reference of the value for sorting:

mLobbyDatabaseRef = mLobbyDatabase.getReference().child("usersDatabase/" + uid + "/" + "lobbyDatabase/" + otherUid + "/");
DatabaseReference mLobbyDatabaseKeyRef = mLobbyDatabaseRef.child("lobbyKey");
mLobbyDatabaseKeyRef.setValue(itemKey);

itemKey will be the value to use sorting. It is also accessible from the items.




<TextView
    android:id="@+id/lobby_key_textview"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:text=""
    android:textColor="@android:color/transparent"
    android:textSize="8sp"/>

Upvotes: 0

Views: 281

Answers (1)

Max Voisard
Max Voisard

Reputation: 1942

Is something like this what you are looking for? Note it has the options of sorting by ascending or descending order, taking advantage of the Collections class and the setAdapter() method.

private ListView lv;
private static ArrayList<String> itemKey = new ArrayList<>();

private void sortData(boolean asc)
{
    if (asc)
       Collections.sort(itemKey);
    else
       Collections.reverse(itemKey);

    lv.setAdapter(new ArrayAdapter(MainActivity.this, android.R.layout.simple_list_item_1, itemKey));
}

If the Collections class and ArrayList doesn't work, and if you were referring to an adapter like the FirebaseListAdapter, then try something like this, using the orderByChild() method to sort into ascending order:

private ListView lv;
Query queryRef = mLobbyDatabaseRef.orderByChild("itemKey");
FirebaseListAdapter<Your_DB_Name> firebaseListAdapter = new FirebaseListAdapter<Your_DB_Name>(this, Your_DB_Name.class, android.R.layout.simple_list_item_1, queryRef) 
{
    @Override
    protected void populateView(View lobby_key_textview, Your_DB_Name model, int position)
    { 
        String itemKey = String.valueOf(model.getItemKey());
        ((TextView)lobby_key_textview.findViewById(android.R.id.text1)).setText(itemKey);
    }
};

lv.setAdapter(firebaseListAdapter);

Upvotes: 1

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