Comment flouter un widget en flutter

J'utilise des exemples BackdropFilter et Position.fill:

import 'dart:ui' as ui;

 Widget buildBlur({@required BuildContext context, @required Widget child}) {
    return Stack(
      children: <Widget>[
        child,
        Positioned.fill(
            child: BackdropFilter(
              filter: ui.ImageFilter.blur(
                sigmaX: 1.0,
                sigmaY: 1.0,
              ),
              child: Center(
               child: XedProgress.indicator(), // replace your widget
             ),
           ),
         )
      ],
    );
  }

Widget de filtre de flou

import 'dart:ui';

import 'package:flutter/material.dart';

class BlurFilter extends StatelessWidget {
  final Widget child;
  final double sigmaX;
  final double sigmaY;
  BlurFilter({this.child, this.sigmaX = 5.0, this.sigmaY = 5.0});

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: <Widget>[
        child,
        ClipRect(
          child: BackdropFilter(
            filter: ImageFilter.blur(
              sigmaX: sigmaX,
              sigmaY: sigmaY,
            ),
            child: Opacity(
              opacity: 0.01,
              child: child,
            ),
          ),
        ),
      ],
    );
  }
}

Usage

import 'package:flutter/material.dart';
import 'package:my_app/widgets/blur_filter.dart';

class WidgetToImage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('blur filter'),
      ),
      body: SingleChildScrollView(
        child: Column(
          children: <Widget>[
            Text('123'),
            Text('999'),
            BlurFilter(
              child: Text('1000'),
            ),
            Text('888'),
          ],
        ),
      ),
    );
  }
}

Nous avons besoin de 3 choses pour créer un widget flou

• 1. pile
• 2.BackdropFilter
• 3.ImageFilter.blur

Stack(
     children: <Widget>[
       Container(child: Text( "Hello")),              // First child
       BlurryEffect(0.5,0.1,Colors.grey.shade200)    //  Second Child
     ],
)

Et,

class BlurryEffect extends StatelessWidget {
  final double opacity;
  final double blurry;
  final Color shade;

  BlurryEffect(this.opacity,this.blurry,this.shade);

    @override  Widget build(BuildContext context) {
    return Container(
      child: ClipRect(
        child:  BackdropFilter(
          filter:  ImageFilter.blur(sigmaX:blurry, sigmaY:blurry),
            child:  Container(
              width: double.infinity,
              height:  double.infinity,
              decoration:  BoxDecoration(color: shade.withOpacity(opacity)),
             ),
           ),
          ),
        );
  }
}

Voici un exemple de code:

import 'dart:ui' as ui;

 Widget backdropFilterExample(BuildContext context, Widget child) {
    return Stack(
      fit: StackFit.expand,
      children: <Widget>[
        child,
        BackdropFilter(
          filter: ui.ImageFilter.blur(
            sigmaX: 8.0,
            sigmaY: 8.0,
          ),
          child: Container(
            color: Colors.transparent,
          ),
        )
      ],
    );
  }

Google propose également un exemple de code sur:

https://api.flutter.dev/flutter/widgets/BackdropFilter-class.html