比较新的解释

https://juejin.im/entry/5c85c959f265da2d881b5eb8

 https://my.oschina.net/u/1464083/blog/2978809

flutter  Dynamic updates

 flutter OtaUpdate  CodePush

https://blog.csdn.net/weixin_30512027/article/details/85772097

https://msd.misuland.com/pd/3127746505234976194

https://my.oschina.net/wupeilin/blog/3035732

唯一找到的 APP热更新资料

https://github.com/dengyin2000/dynamic_widget

Code Push/Hot update

我们现在使用flutter更新版本

下载apk：
引入
dependencies:
flutter_downloader: 1.1.3

taskId = await FlutterDownloader.enqueue(
url: url,//服务端提供apk文件下载路径
savedDir: (await getExternalStorageDirectory()).path.toString(),//本地存放路径
fileName: “xiangta_” + netCode + “.apk”,//存放文件名
showNotification: false,//是否显示在通知栏
openFileFromNotification: false,//是否在通知栏可以点击打开此文件
);

//taskId为任务id （与完成下载的文件成一一对应）open是执行打开 打开需要任务id 相信你已经找到方向了
FlutterDownloader.registerCallback((taskId, status, progress) {
if (status == DownloadTaskStatus.complete) {
//下载完成
FlutterDownloader.open(taskId:taskId));
} else if (status == DownloadTaskStatus.failed) {
//下载出错
}
});

———

一、使用FlutterDownloader下载

二、open_file打开文件自带安装（FlutterDownloader自带打开文件，但不能打开app不知道为啥）

代码：

1、下载监听 

FlutterDownloader.registerCallback((id, status, progress) {
      print(
          'Download task ($id) is in status ($status) and process ($progress)');
      if (status == DownloadTaskStatus.complete) {
        OpenFile.open(_localPath);
        FlutterDownloader.open(taskId: id);
      }
    });
2、下载

final taskId = await FlutterDownloader.enqueue(
  url: url,
  savedDir: _localPath,
  showNotification:
      true, // show download progress in status bar (for Android)
  openFileFromNotification:
      true, // click on notification to open downloaded file (for Android)
);
final tasks = await FlutterDownloader.loadTasks();