您应该使用
RepaintBoundary 将其捕获为小部件并使用
栈 覆盖小部件。
看一下这段代码，如何将小部件捕获为图像。
import 'dart:async';import 'dart:convert';import 'dart:typed_data';import 'dart:ui' as ui;import 'package:flutter/material.dart';import 'package:flutter/rendering.dart';void main() => runApp(new MyApp());class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return new MaterialApp( title: 'Flutter Demo', theme: new ThemeData( primarySwatch: Colors.blue, ), home: new MyHomePage(), ); }}class MyHomePage extends StatefulWidget { @override _MyHomePageState createState() => new _MyHomePageState();}class _MyHomePageState extends State<MyHomePage> { GlobalKey _globalKey = new GlobalKey(); bool inside = false; Uint8List imageInMemory; Future<Uint8List> _capturePng() async { try { print('inside'); inside = true; RenderRepaintBoundary boundary = _globalKey.currentContext.findRenderObject(); ui.Image image = await boundary.toImage(pixelRatio: 3.0); ByteData byteData = await image.toByteData(format: ui.ImageByteFormat.png); Uint8List pngBytes = byteData.buffer.asUint8List();// String bs64 = base64Enpre(pngBytes);// print(pngBytes);// print(bs64); print('png done'); setState(() { imageInMemory = pngBytes; inside = false; }); return pngBytes; } catch (e) { print(e); } } @override Widget build(BuildContext context) { return RepaintBoundary( key: _globalKey, child: new Scaffold( appBar: new AppBar( title: new Text('Widget To Image demo'), ), body: SingleChildScrollView( child: Center( child: new Column( mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ new Text( 'click the button below to capture image', ), new RaisedButton( child: Text('capture Image'), onPressed: _capturePng, ), inside ? CircularProgressIndicator(): imageInMemory != null? Container(child: Image.memory(imageInMemory),margin: EdgeInsets.all(10)): Container(), ], ), ), )), ); }}
