Is there a way in Flutter to detect which part of a Widget was pressed?

Is there a way in Flutter to detect which side of a button is pressed? For example, in the attached image, is it possible to tell when the '5' button is pressed whether the user pressed their finger on the 'A', 'B', 'C' or 'D' part or a combination of these?

The idiomatic way to do this in Flutter is to break down the top-level widget into subwidgets, in your case one for each element in the screenshot. Then you can handle the onTap for each of these subwidgets.

If you want to handle this with a single widget, that is possible too though. To detect where on a widget the user taped, you can implement GestureDetector. Check out the examples in that documentation.

For this specific use-case, have a look at onTapDown as the TapDownDetails contains information about where exactly the tap happened.