firemonkeyc++builder-10.2-tokyo

change ListView item image at runtime (firemonkey)

I need the ability for a user to press and set an ListView item's checkbox independently of clicking on the item. If they press on the checkbox I will add/remove the checkmark and take some action. If they press on the item text I can take another action.

I can do this with a ListBox no problem with built in functionality. I can't figure out how to do it with a ListView. How is it done?

I can put the following code in the ListView1ItemClickEx to know when the user is clicking on the image. Maybe I can just change the image to a checkmark? 

  if (ItemObject->Name == "I") {
     ShowMessage("Item Image clicked");
  }

But I don't know how to change that particular items image (e.g. I could just toggle between a checkmark image and an unchecked image) at runtime.

The picture below is for clarity. Clicking anywhere in the red box will change the items checkbox. For the ListBox clicking anywhere in the blue box will fire the OnClick event and not change the checkbox. I want that same behavior in the ListView.

enter image description here

Solution

  • Ok, Remy answered this related question and it helped me solve this issue. Now I can make the ListView have a checkbox that functions like that of the ListBox. I do it by toggling the item image whenever the user presses (or clicks on) the image area of an item.

    When the user clicks an items image I trap it (per Remy's code in the ListView1ItemClickEx event) and toggle it from 0->1 or 1->0 in a vector at reference ItemIndex (e.g. myVector[ItemIndex] = 0) and then I completely rebuild the ListView (clear it and build from scratch).

    enter image description here

    I thought I'd have to remember where in the list I had scrolled down to and after refreshing the ListView I'd have to scroll to that point in code - but, that isn't the case. I don't know why but after the refresh I'm still at the point in the list where I clicked an item image. It makes it work and feel exactly like a check box.

    It works great in iOS, Android, and Windows.

    p.s. I forgot to mention that you need to treat any Header's like they are items in your vector that keeps up with each items' image (0 or 1). Otherwise adding headers gets you out of sync and clicking an item's image will toggle some other item's image.