FlutterWebviewPlugin侦听器不能将*.pdf识别为url

Question

我在Flutter中有一个webview和一个链接到http://mywebsite.com/dummy.pdf的网页

问题是，当用户点击pdf链接时，webview监听器不会监听。

flutterWebviewPlugin.onUrlChanged.listen((String url) async {
      if (url.contains('.pdf')) {
        print(url); //This print is never done
      }
      if (url.contains('mailto:')) {
        print(url); //This print is ok
      }
      if (url.contains('txt')) {
        print(url); //This print is ok
      }
      if (url.contains('foobar')) {
        print(url); //This print is ok
      }
    }

如何解决这个问题？

更新1

这个问题与那些指向“非托管”文件的urls有关。

flutterWebviewPlugin.onUrlChanged.listen((String url) async {
      if (url.contains('.pdf')) {
        print(url); //This print is never done
      }
      if (url.contains('.doc')) {
        print(url); //This print is never done
      }
      if (url.contains('mailto:')) {
        print(url); //This print is ok
      }
      if (url.contains('.txt')) {
        print(url); //This print is ok
      }
      if (url.contains('.mp3')) {
        print(url); //This print is ok
      }
    }

Answer 1

我不知道这是不是更好的方法，但如果问题只与pdf有关，那么我们只能通过Dart编程方法来解决这个问题。

但是，我觉得您也必须检查一下这一点：url.contains('pdf')，而不是在contains()中使用.pdf

因此，现在的解决方法是执行以下操作：

1. Check the length of the url 
2. Since the pdf would come at the last, so we need the last three items
3. Check if it is `pdf` only or not, like pdfString = Substring of the String of last three chars // In this way you  get the last three elements of the url
4. Do a check whether pdfString == 'pdf', if yes, print('OK') else // do something

最终解决方案

// This is a workaround for pdf only, so writing the code for that only
flutterWebviewPlugin.onUrlChanged.listen((String url) async {
   // technically this should give you the last three chars, which is pdf in this case
   var pdfString = url.substring(url.length-3); 

   // now checking if the pdfString contains that pdf or not
   if(pdfString == 'pdf'){
     //print your url
     print(url); // OUTPUT WILL BE http://mywebsite.com/dummy.pdf
   }
}

我希望，您会发现这足够有用，可以将其合并到代码中。如果pdf的url总是以.pdf结尾，这是一种可行的解决方案，。让我知道这是给你的，直到那时快乐的学习:)