flutter - 为什么画面在每个时间段都没有变化？

Question

我希望我的 float 网页显示一张照片，并每3秒更改一次以显示另一张照片。
这是我的代码

class _contactPageState extends State<contactPage> {

List<String> randomPics= ['profiles/github.png', 'profiles/linkedIn.png', 'profiles/stack.png'];
Timer timer;
var random= Random();
String photo;

@override
void initState() {
photo = randomPics[random.nextInt(randomPics.length)];
openLink = new linksToOpen();
super.initState();
timer = new Timer(new Duration(seconds: 1), ( ){
  setState(() {
    photo= randomPics[random.nextInt(randomPics.length)];
    print('${photo}');
  });
});
}
  @override
Widget build(BuildContext context) {
    Container(
           
      child: Image(image : AssetImage(photo),gaplessPlayback: true,),
        width: 400, height: 400,
                
                ),

我的代码有什么问题？
拜托，谁能帮我!

Answer 1

我做了一些测试，我认为这可能对您有用:

import 'dart:async';
import 'dart:math';

import 'package:flutter/widgets.dart';

class ContactPageState extends StatefulWidget {
  ContactPageState({Key key}) : super(key: key);

  @override
  _ContactPageState createState() => _ContactPageState();
}

class _ContactPageState extends State<ContactPageState> {
  List<String> randomPics = ['assets/a.jpg', 'assets/b.jpg', 'assets/c.jpg'];
  String photo;
  final random = new Random();

  void initState() {
    WidgetsBinding.instance.addPostFrameCallback((_) => configureTimer());
    super.initState();
  }

  configureTimer() {
    Timer.periodic(Duration(milliseconds: 3000), (timer) {
      final int index = random.nextInt(randomPics.length);
      setState(() {
        photo = randomPics[index];
        debugPrint('Select picture $photo in index $index');
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Image(
        image: AssetImage(photo != null ? photo : 'assets/a.jpg'),
        gaplessPlayback: true,
      ),
      width: 400,
      height: 400,
    );
  }
}