can not load local images with html data string

Hello, sir
I met an issue about loading images that are stored locally .
I tried using
```
return WebviewScaffold(
url: new Uri.dataFromString(widget.topicContentEntity.content,
mimeType: 'text/html', encoding: Encoding.getByName("utf-8"))
.toString(),
withJavascript: true,
withLocalUrl: true,
allowFileURLs: true,
);

```
the local html string contains
`""`

but it always failed to load local image with this warning
\"flutter webview not allowed to load local resource\"

before , I used
https://developer.android.com/reference/android/webkit/WebView.html#loadDataWithBaseURL ?
with native android code to load the html string and the image.