Register tap on empty space around widget - flutter

Question

Working on a flutter web project. I have a row which has 3 widgets:
From left to right:
Sidebar
Sidebar content
body
Widget _buildBody() {
final screenwidth = MediaQuery.of(context).size.width;
editpanel = screenwidth * 0.3;
final editor = ViewProvider.of(context).isEditPanelOpen
? (screenwidth - sidebar - editpanel)
: (screenwidth - sidebar);
final ViewProvider viewProvider = Provider.of<ViewProvider>(context);
return Row(
Sidebar()
_loadSidebarContent(bloc.editPanelIndex),
_sidebarHandler(viewProvider),
Center(
child: SizedBox(
width: editor * 0.8,
child: Center(
child: MyWidget(),
),
),
),
],
);
}
I need to register tap if user taps on anything except the Appbar, Sidebar, Sidebarcontent, on MyWidget.
So I wrapped the entire scaffold with gesture detector and tried using IgnorePointer for the specific widgets.
Widget build(BuildContext context) {
return GestureDetector(
onTap: () {
.. call some specific function
},
child: Scaffold(
backgroundColor: Colors.white,
appBar: PreferredSize(
preferredSize: Size(
MediaQuery.of(context).size.width,
height + 80,
),
child: IgnorePointer(
child: Appbar(),
ignoring: true,
),
),
body: _buildBody(),
),
);
}
Issue is: MyWidget is getting ignored all the time. I don't want to fire the specificFunc() when user taps on any of the: Appbar, Sidebar, Sidebarcontent, or MyWidget.
Basically if user taps the white space around MyWidget specificFunction will be called

Answer 1

Wrap the whole Scaffold widget with GestureDector is not a good idea.
Instead wrap the container (white space around your button) with the detector and supply the button as a child.
In the following sample, the amber area is your white one. Tapping the amber area, and the button produces a separate log.
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Expanded(
child: GestureDetector(
onTap: () {
if (kDebugMode) {
print('Amber area tapped!');
}
},
child: Container(
color: Colors.amber,
width: 400,
height: 400,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
TextButton(
style: ButtonStyle(
foregroundColor:
MaterialStateProperty.all<Color>(Colors.blue),
backgroundColor: MaterialStateProperty.all<Color>(
Colors.white)),
onPressed: () {
if (kDebugMode) {
print('Button clicked.');
}
},
child: const Text('A Button'),
),
],
)),
),
)
],
),
),
);
}
}

Answer 2

You could use a stack (https://api.flutter.dev/flutter/widgets/Stack-class.html) and wrap the widget at the very bottom of the stack with a gesture detector.
To position the other widgets correctly, you could use the Positioned widget.

Answer 3

Instead of ignorePointer you should be using AbsorbPointer which will absorb the pointer and not pass it to the content below it