Firemonkey ListBox Item with image

Question

i made a Firemonkey custom ListBox Item, designed with a stylebook. When i try to insert ListBox items, everything works fine (insert text etc.) except to change the picture in the ListBox Item.

I followed this tutorial on: http://www.experts-exchange.com.

Here is my code:

procedure TForm2.Button1Click(Sender: TObject);
var
    i         : Integer;
    LBItem    : TListBoxItem;
    ItemImage : Timage;
begin
    ListBox1.BeginUpdate;
    ListBox1.Items.Clear;
    try
        for i := 0 to 9 do begin

            LBItem := TListBoxItem.Create(nil);
            LBItem.Parent := ListBox1;
            LBItem.StyleLookup := 'rowLayout';
            LBItem.StylesData['textName'] := 'Some text...';
            LBItem.StylesData['textFormat'] := 'Some more text...';

            ItemImage := LBItem.FindStyleResource('picture') as TImage;
            if Assigned(ItemImage) then
                LBItem.ItemData.Bitmap.LoadFromFile('D:\MyTestPicture.jpg');
        end;
    finally
        ListBox1.EndUpdate;
    end;
end;

"rowLayout" is my layout in the stylebook, i made for the ListBox Item. "textName" and "textFormat" are some TText, which i placed in the ListBox Item. "picture" is the TImage in my ListBox Item.

What is going wrong with my code? I am working with Delphi XE4.

Thanks for your help and best regards, Holger

Solution

Your picture does not change because in your code you are only loading a single image. You also made a big mistake of constantly loading the image in a loop, you should only load the image once when the form is created and then simply reference the correct Bitmap.

if Odd(I) then
    Item.ItemData.Bitmap := Image1.Bitmap         
  else
    Item.ItemData.Bitmap := Image2.Bitmap; 

The irony is that most people forget to check the Samples folder, most usually located at C:\Users\Public\Documents\RAD Studio\XX.0\Samples\FireMonkey.

What you should do is take a close look at the CustomListBoxsample.

There is nothing wrong with following other tutorials but given how fast Firemonkey changes each version and the tutorial that you linked being quite old, I would suggest you fall back to the already included Delphi example, it's up to date, easy to understand and basically does exactly what you are looking for.

Comments

[HolgerH]

Hi Peter, thanks for your answer! I taked a deep look at the Demo folder, but when i tried to implement it in my program, it dosent work with the image. But now, i played a bit with the "style Name". And i find out, when i use the style name: "icon" then does the following code work perfect: LBItem.ItemData.Bitmap.LoadFromFile(folder + '\' + TJSONPair(item).JsonValue.Value); When i changed the style name from my image to something else, it dosent work. Best regards, Holger

[Machado]

@HolgerH what exactly does "style Name" represent? Is it the StyleName propertie from the ListBox? Or is it LBItem.FindStyleResource('icon') the solution?