flutter - 使用 flutter，每次我重新加载 ListView 时，我的带有 MemoryImage 的 CircleAvatar 都会闪烁

Question

我正在使用 CircleAvatar 的 backgroundImage 属性中的 MemoryImage 渲染 base64 图像，并经常重新加载 ListView，每次 ListView 重新加载时，图像中都会出现非常明显的闪烁，从蓝色圆圈开始，然后变成适当的图像。我想知道如何摆脱闪烁。

这是一个完整的例子:

import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Image Flickering Example',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Image Flickering Example'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String img = "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";

  Widget body = Text("...");
  void _updateListView() {
    Widget listView = ListView.builder(
      itemCount: 1,
      itemBuilder: (BuildContext context, int index){
        return Card(
          child: CircleAvatar(
            backgroundImage: MemoryImage(base64Decode(img)),
          ),
        );
      },
    );
    setState(() {
      body = listView;
    });
  }

  Timer listRefreshTimer;
  void listRefresher(){
    const oneSec = const Duration(seconds: 1);
    listRefreshTimer = new Timer.periodic(oneSec,(Timer t){
      _updateListView();
    });
  }

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    listRefresher();
  }


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body:body
      );
  }
}

Answer 1

将解码的结果移动到一个变量中，这样它就不会在每次状态更新时重新运行:

class _MyHomePageState extends State<MyHomePage> {
  final img = base64Decode("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");

  Widget body = Text("...");
  void _updateListView() {
    Widget listView = ListView.builder(
      itemCount: 1,
      itemBuilder: (BuildContext context, int index) {
        return Card(
          child: CircleAvatar(
            maxRadius: 40,
            backgroundImage: MemoryImage(img),