DART/FLUTTER: How to get access to member variable / values of Widgets - list

Question

I have an list of widgets. The widgets are background images for a website. The last widget(image) in this list is displayed onscreen. As nav functions push/pop, the last element is removed/added.
One of the fields in the Widget(BackdropImage) is a bool called 'isForeground'. I need access to it.
Why? Some background images are foreground and are to be rendered above the site's semi-transparent background texture, some are to be rendered behind it.
If I have a List(BackDropImage) and the BackDropImage contains:
Path, BoxFit, Opacity, isForeground(bool) etc etc. How can I get access to the last BackDropImage in BackDropImage list and access its isForground field?
//PSUDO WIDGET TREE:
if(backdropImageList.last's 'isForground' field is FALSE) BackDropImage.last,//render here below the texture
BackgroundTextureWidget,
if(backdropImageList.last's isForground field is TRUE) BackDropImage.last //render here above the texture
HeadingWidget,
OtherWidgets
I'd appreciate help if possible (or alternative approaches). The alterative is to flip a bool programmatically every time a button is pressed/popped and keeping track of what images are displayed where. Knowing which images are fore/background in the first place and controlling from the object itself is much neater IMO.
Thanks folks.

Answer 1

list.firstWhere((x) => x['isForground'] == true);

Answer 2

Widget is an abstract class. When working with Widgets like Container etc that have member variables you need to access programmatically, it can be done like this:
Widget testContainer = Container (width:100)
print(testContainer.width) // WON'T WORK
print((testContainer as Container).width) // WILL WORK
To access the member variables of individual Widgets in a list of Widgets:
List<Widget> listOfWidgets = [Container(color:Colors.blue), Container(color:Colors.red), Container(color:Colors.green)]
void printColorsOfAllContainers () {
for (var element in listOfWidgets) {
if (element is Container) {
print(element.color);
}
}
}
Alternatively, you can also do things like this:
void printColorsOfAllContainers() {
final List<Color> listOfContainerColours = [];
for (var element in listOfWidgets) {
element as Container;
listOfContainerColours.add(element.color!);
}
}