Grouping items inside TListView object?

Question

I am trying to group the items inside TListView object, but I cant find the class responsible for grouping the objects, neither i were able to find such inside the documentation.

• What is the class responsible about grouping items inside TListView object, and how to use it properly ?

The platform is Firemonkey ( Android/iOS) / Delphi XE6

Answer 1

The property I believe you're referring to is TListGroups, a collection that holds TListGroup items. There's a demo provided in the Delphi documentation.

Unfortunately, it's only available in the VCL and not FMX, as the underlying functionality is part of the Windows ListView control that TListView wraps.

The closest you can get in FMX is using TListBox and a TListBoxGroupHeader, which is covered in the Multi-Device Tutorial Using ListBox Components to Display a Table View (iOS and Android) in the docwiki:

procedure TForm1.FormCreate(Sender: TObject);
var
  c: Char;
  i: Integer;
  Buffer: String;
  ListBoxItem : TListBoxItem;
  ListBoxGroupHeader : TListBoxGroupHeader;
begin
  ListBox1.BeginUpdate;
  for c := 'a' to 'z' do
  begin
    // Add header ('A' to 'Z') to the List
    ListBoxGroupHeader := TListBoxGroupHeader.Create(ListBox1);
    ListBoxGroupHeader.Text := UpperCase(c);
    ListBox1.AddObject(ListBoxGroupHeader);

    // Add items ('a', 'aa', 'aaa', 'b', 'bb', 'bbb', 'c', ...) to the list
    for i := 1 to 3 do
    begin
      // StringOfChar returns a string with a specified number of repeating characters.
      Buffer := StringOfChar(c, i);
      // Simply add item
      // ListBox1.Items.Add(Buffer);

      // or, you can add items by creating an instance of TListBoxItem by yourself
      ListBoxItem := TListBoxItem.Create(ListBox1);
      ListBoxItem.Text := Buffer;
      // (aNone=0, aMore=1, aDetail=2, aCheckmark=3)
      ListBoxItem.ItemData.Accessory := TListBoxItemData.TAccessory(i);
      ListBox1.AddObject(ListBoxItem);
    end;
  end;
  ListBox1.EndUpdate;
end;

This produces (image from the indicated docwiki)

Answer 2

This is easily accomplished in FMX TListview control while using Livebindings by connecting your TListviewItem.header.break field to the fieled you want to group on (it will be a field in your db that is redundant over many records).