图片缓存相关

1、清除图片缓存

由于动态图加载完成后，由于缓存原因，再次加载图片时，会直接从缓存读取最后一帧的画面。需要清缓存后预加载图片

// 清除图片缓存
void clearImageCache(AssetBundleImageKey key) {
  final ImageCache imageCache = PaintingBinding.instance.imageCache;
  imageCache.evict(key);
}

2、获取AssetBundleImageKey

  AssetBundleImageKey getAssetBundleImageKey(ImageProvider provider, BuildContext context) async {
    final ImageConfiguration config = createLocalImageConfiguration(context);
    return await provider.obtainKey(config);
  }

3、预加载图片

void preLoadImage(ImageProvider provider, BuildContext context) {
    return precacheImage(provider, context)
 };

参考：https://book.flutterchina.club/chapter14/image_and_cache.html