Question

我已经使用资产图像构建了骰子掷骰动画，但是该图像最后仅更新一次，但是使用循环生成了6次随机骰子数。

import 'package:dicee/dice_model.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

void main() {
  return runApp(
    MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: ChangeNotifierProvider<DiceModel>(
          child: DicePage(),
          create: (BuildContext context) => DiceModel(),
        )),
  );
}

class DicePage extends StatelessWidget {
  void updateDices(DiceModel dice) {
    for (int i = 0; i < 6; i++) {
      print(i);
      sleep(Duration(milliseconds: 1000));
      dice.generateDiceOne();
    }
  }

  @override
  Widget build(BuildContext context) {
    List<String> _diceOneImages = [
      "images/dice1.png",
      "images/dice2.png",
      "images/dice3.png",
      "images/dice4.png",
      "images/dice5.png",
      "images/dice6.png",
    ];
    final dice = Provider.of<DiceModel>(context);
    final c = dice.diceOneCount;
    var img = Image.asset(
      _diceOneImages[c - 1],
      gaplessPlayback: true,
    );
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        Row(
          children: <Widget>[
            Expanded(
              child: GestureDetector(
                onTap: () => updateDices(dice),
                child: img,
              ),
            ),
          ],
        ),
      ],
    );
  }
}```

**DiceModel**

```import 'dart:math';

import 'package:flutter/foundation.dart';

class DiceModel with ChangeNotifier {
  int diceOne = 1;

  int get diceOneCount => diceOne;

  void generateDiceOne() {
    diceOne = Random().nextInt(5) + 1;
    print("diceOne: $diceOne");
    notifyListeners();
  }
}```

Answer 1

问题是您正在呼叫sleep(Duration(milliseconds: 1000));。如果您检查日志，则应该得到UnsupportedError以及消息"This embedder disallows calling dart:io's sleep()"。该功能仅在主/ UI隔离之外的隔离（Dart线程）上起作用。因此，下一行代码dice.generateDiceOne();永远不会执行。

改为使updateDices异步，并将sleep替换为await Future.delayed(const Duration(seconds: 1));。

骰子卷动画颤动

1 个答案: