flutter_inappwebview请求http报错This request has been blocked

flutter_inappwebview 请求网页的时候 内部ajax 访问http 会失败，提示如下：
Mixed Content: The page at 'https://<page url>' was loaded over HTTPS, but requested an insecure video 'http://<video url>.mp4'. This request has been blocked; the content must be served over HTTPS.

在配置选项中增加一条
示例代码：
child: InAppWebView(
  initialUrlRequest: URLRequest(url: Uri.parse("https://yourwebsite.com")),
  initialOptions: InAppWebViewGroupOptions(
    android: AndroidInAppWebViewOptions(
      mixedContentMode: AndroidMixedContentMode.MIXED_CONTENT_ALWAYS_ALLOW
    )
  ),
)

我首先使用了一下方式，结果报错依旧，这里也贴出来做个参考。
项目文件夹\android\app\src\main\AndroidManifest.xml
application 中新增两行
android:usesCleartextTraffic="true"
android:networkSecurityConfig="@xml/network_security_config"
新增文件：
项目文件夹\android\app\src\main\res\xml\network_security_config.xml
内容:
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<base-config cleartextTrafficPermitted="true">
<trust-anchors>
<certificates src="system" />
<certificates src="user" />
</trust-anchors>
</base-config>
</network-security-config>