Flutter webview我想在向上或向下拖动应用程序时删除白色背景

import 'package:flutter_webview/flutter_webview.dart';

WebView(
  initialUrl: 'https://example.com',
  javascriptMode: JavascriptMode.unrestricted,
  gestureRecognizers: Set()
    ..add(Factory<VerticalDragGestureRecognizer>(
        () => VerticalDragGestureRecognizer())),
  onPageFinished: (String url) {
    // WebView加载完成后的回调函数
  },
  onWebViewCreated: (WebViewController controller) {
    // WebView创建完成后的回调函数
    controller.setBackgroundColor(Colors.transparent); // 设置背景颜色为透明
  },
)