prefetch method

@VoltronMethod(kFuncPrefetch) bool prefetch(String url, JSPromise promise)

Implementation

@VoltronMethod(kFuncPrefetch)
bool prefetch(String url, JSPromise promise) {
  var img = getImage(url);
  // img.obtainKey(ImageConfiguration());
  // ImageCache().
  img.resolve(const ImageConfiguration()).addListener(ImageStreamListener(
        (image, sync) {
          var img = image.image;
          var params = VoltronMap();
          params.push('width', img.width);
          params.push('height', img.width);
          promise.resolve(params);
        },
        onError: (exception, stackTrace) {
          var err = FlutterErrorDetails(
            context: ErrorDescription('image failed to precache'),
            library: 'image resource service',
            exception: exception,
            stack: stackTrace,
            silent: true,
          );
          var params = VoltronMap();
          params.push('code', 10002);
          params.push('msg', err.toString());
          promise.reject(params);
        },
      ));
  return true;
}