Getting 'Future<String?>' is not a subtype of type 'String' 错误为什么要在 flutter 应用程序中从网站抓取数据？

Question

[此图片包含我从网站获取数据的部分代码 https://arprogramming.blogspot.com/ and storing the data in 3 separate lists. The link list is used to store the link of the blog so that I can use it as a link afterwards to redirect to the site from the app]2

These are all my imports

Thia is my pubspec.yaml file

This is the part of code where I am using the scraped data

THIS IS MY ERROR 下面是我的主要代码

Future<void> _getDataFromWeb() async{
    var uri =Uri.parse('https://arprogramming.blogspot.com/');
    final response = await http.get(uri);
    dom.Document document = parser.parse(response.body);
    final elements =  document.getElementsByClassName('entry-title');
    final content =  document.getElementsByClassName('entry-content');
    final link1 =  document.getElementsByClassName('entry-header blog-entry-header');

    setState(() {
      title =  elements.map((elements)=> elements.getElementsByTagName("a")[0].innerHtml.toString()).toList();
      post =  content.map((content)=> content.getElementsByTagName("p")[0].innerHtml.toString()).toList();
      link =  link1.map((link1) async => link1.getElementsByTagName("a")[0].attributes['href']).cast<String>().toList();
    });

  }

Answer 1

您不能将 Future 用作字符串。因为这些在你想用的时候不一定可用。使用“then”，它让我们知道异步函数何时结束，我们有变量可以使用。

注意：请更加小心进一步的存储库。社区应该清楚地上传他们的代码作为代码片段和错误消息。欢迎

http.get(uri).then((String response){
        dom.Document document = parser.parse(response.body);
        final elements =  document.getElementsByClassName('entry-title');
        final content =  document.getElementsByClassName('entry-content');
        final link1 =  document.getElementsByClassName('entry-header blog-entry-header');
    
        setState(() {
          title =  elements.map((elements)=> elements.getElementsByTagName("a")[0].innerHtml.toString()).toList();
          post =  content.map((content)=> content.getElementsByTagName("p")[0].innerHtml.toString()).toList();
          link =  link1.map((link1) async => link1.getElementsByTagName("a")[0].attributes['href']).cast<String>().toList();
        });
    });

Getting 'Future<String?>' is not a subtype of type 'String' 错误为什么要在 flutter 应用程序中从网站抓取数据？

Getting 'Future<String?>' is not a subtype of type 'String' error why scraping data from a website in flutter app?

flutter

flutter-test

flutter-dependencies

flutter-animation

flutter-web