Flutter Dio Package：如何监听另一个类的下载进度？

Question

我有一个DownloadsService类使用包处理文件下载dio。我想听一下我的ViewModel类中实现类downloadFile内方法的下载进度DownloadService。我该怎么做呢？

这是我的DownloadsService课程代码片段：

class DownloadsService {
   final String urlOfFileToDownload = 'http://justadummyurl.com/'; //in my actual app, this is user input
   final String filename = 'dummyfile.jpg';
   final String dir = 'downloads/$filename'; //i'll have it saved inside internal storage downloads directory

   void downloadFile() {
     Dio dio = Dio();
     dio.download(urlOfFileToDownload, '$dir/$filename', onReceiveProgress(received, total) {
        int percentage = ((received / total) * 100).floor(); //this is what I want to listen to from my ViewModel class
     });
   }
}

这是我的ViewModel课：

class ViewModel {
   DownloadsService _dlService = DownloadsService(); //note: I'm using get_it package for my services class to make a singleton instance. I just wrote it this way here for simplicity..

      void implementDownload() {

       if(Permission.storage.request().isGranted) { //so I can save the file in my internal storage
          _dlService.downloadFile();

        /*
         now this is where I'm stuck.. My ViewModel class is connected to my View - which displays
         the progress of my download in a LinearProgressIndicator. I need to listen to the changes in
         percentage inside this class.. Note: my View class has no access to DownloadsService class. 
       */

      }        
   }
}

Dio 文档提供了一个关于如何将响应类型转换为流/字节的示例。但是它没有给出任何关于如何在下载文件时执行此操作的示例。有人能指出我正确的方向吗？我现在真的很困惑..非常感谢你！

Answer 1

我正是这个问题

我解决了模型中的依赖注入问题

实际上，我在模型中定义了进度字段（双精度），用于监听下载百分比，并将模型中的一个对象定义到 GetX 控制器中（您可以使用任何依赖项注入，如 getIt，...），因此使用实时数据机制，这个问题将如此轻松地解决