flutter 播放帧动画

谢谢支持原文：http://tryenough.com/flutter-frame-animal

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本文是关于如何循环播放一连串的图片，形成动画效果。

看下效果：

你需要做的就是把UI提供的一系列图片传入到下列代码中，并设置宽高。

工具类封装：

import 'package:flutter/material.dart';

class ImagesAnim extends StatefulWidget {
  final Map<int, Image> imageCaches;
  final double width;
  final double height;
  final Color backColor;

  ImagesAnim(this.imageCaches, this.width, this.height, this.backColor, {Key key})
      : assert(imageCaches != null),
        super(key: key);

  @override
  State<StatefulWidget> createState() {
    return new _WOActionImageState();
  }
}

class _WOActionImageState extends State<ImagesAnim> {
  bool _disposed;
  Duration _duration;
  int _imageIndex;
  Container _container;

  @override
  void initState() {
    super.initState();
    _disposed = false;
    _duration = Duration(milliseconds: 800);
    _imageIndex = 1;
    _container = Container(height: widget.height, width: widget.width);
    _updateImage();
  }

  void _updateImage() {
    if (_disposed || widget.imageCaches.isEmpty) {
      return;
    }

    setState(() {
      if (_imageIndex > widget.imageCaches.length) {
        _imageIndex = 1;
      }
      _container = Container(
          color: widget.backColor,
          child: widget.imageCaches[_imageIndex],
          height: widget.height,
          width: widget.width);
      _imageIndex++;
    });
    Future.delayed(_duration, () {
      _updateImage();
    });
  }

  @override
  void dispose() {
    super.dispose();
    _disposed = true;
    widget.imageCaches.clear();
  }

  @override
  Widget build(BuildContext context) {
    return _container;
  }
}

谢谢支持原文：http://tryenough.com/flutter-frame-animal

使用：

//imageCaches 是图片map
Center(
    child:ImagesAnim(imageCaches, 100, 150, Colors.transparent),
),