How to get widget's absolute coordinates on a screen in Flutter?

Question

How to get widget's absolute coordinates on a screen in Flutter?

Or its offset in a parent

Example:

import 'package:flutter/material.dart';  void main() => runApp(MyApp());  class MyApp extends StatelessWidget {   @override   Widget build(BuildContext context) {     return MaterialApp(       title: 'Simple app',       theme: ThemeData(         primarySwatch: Colors.blue,       ),       home: SimpleScreen(         title: 'Simple screen',       ),     );   } }  class SimpleScreen extends StatefulWidget {   final String title;    SimpleScreen({Key key, this.title}) : super(key: key);    @override   _SimpleScreenState createState() => new _SimpleScreenState(); }  class _SimpleScreenState extends State<SimpleScreen> {   @override   Widget build(BuildContext context) {     return Scaffold(       appBar: AppBar(         title: Text(widget.title),       ),       body: Center(         child: Container(           width: 48.0,           height: 48.0,           color: Colors.blue,         ),       ),     );   } } 

Goal is to get Container's offset in parent. If Center's size is 48.0, then Container's offset in Center's parent/root

Condition: you don't know the wrapper layout (it's a library widget), should be flexible, without hardcoded values

Thanks

Answer 1

You can use this extension I wrote (requires Dart 2.6):

extension GlobalKeyExtension on GlobalKey {   Rect? get globalPaintBounds {     final renderObject = currentContext?.findRenderObject();     final translation = renderObject?.getTransformTo(null).getTranslation();     if (translation != null && renderObject?.paintBounds != null) {       final offset = Offset(translation.x, translation.y);       return renderObject!.paintBounds.shift(offset);     } else {       return null;     }   } }  

Example how to use it:

final containerKey = GlobalKey();  Container(   key: containerKey,   width: 100,   height: 50, )  void printWidgetPosition() {   print('absolute coordinates on screen: ${containerKey.globalPaintBounds}'); } 

Answer 2

Maybe this simple widget is what you want : rect_getter 0.0.1

This is a widget provide a simple way to get child's rectangle information after rendered.