Opening In app links when it contains the specified URL

Hi! so I am using flutter for the first time and I have just been playing around with the webview_flutter widget and I am currently struggling to figure out a way to check if the URL of the webview contains a specific URL. If it does contain that URL, it will open it in the specified app. In this example, I want to use Google Drive. If the webview contains a google drive link, then open it in Google Drive. Where do I even begin with this if statement? May i get some help here? Thanks!

If you check the example webview_flutter example You will see a property called navigationDelegate, adding code below:

          navigationDelegate: (NavigationRequest request) {
            if (request.url.startsWith('https://www.youtube.com/')) {
              print('blocking navigation to $request}');
              return NavigationDecision.prevent;
            }
            print('allowing navigation to $request');
            return NavigationDecision.navigate;
          },
          onPageStarted: (String url) {
            print('Page started loading: $url');
          },
          onPageFinished: (String url) {
            print('Page finished loading: $url');
          },
          gestureNavigationEnabled: true,
          backgroundColor: const Color(0x00000000),
        );
      }),