loadImage method

void loadImage(VoidCallback onComplete)

Load image from disk cache first, if not found then load from network. onComplete is called when imageBytes become available.

Implementation

void loadImage(VoidCallback onComplete) {
  if (this.frames != null) {
    this.state = LoadState.success;
    onComplete();
  }

  final fileStream = DefaultCacheManager().getFileStream(this.url,
      headers: this.requestHeaders as Map<String, String>?);

  fileStream.listen(
    (fileResponse) {
      if (!(fileResponse is FileInfo)) return;
      // the reason for this is that, when the cache manager fetches
      // the image again from network, the provided `onComplete` should
      // not be called again
      if (this.frames != null) {
        return;
      }

      final imageBytes = fileResponse.file.readAsBytesSync();

      this.state = LoadState.success;

      ui.instantiateImageCodec(imageBytes).then((codec) {
        this.frames = codec;
        onComplete();
      }, onError: (error) {
        this.state = LoadState.failure;
        onComplete();
      });
    },
    onError: (error) {
      this.state = LoadState.failure;
      onComplete();
    },
  );
}