Clean up api

While the <kbd>flutter_downloader</kbd> works fine, its API doesn’t conform to idiomatic Dart standards in some cases. That’s why I’m currently rewriting the Dart side of the plugin to make it more intuitive. If implemented, this will be a breaking change and thus require a new major version update.

Especially the DownloadTasks are currently merely a wrapper around some data and not really actionable. I’m looking forward to rewriting the API so that something like the following is possible:

final task = await DownloadTask.create(
  url: 'https://...',
  downloadDirectory: getApplicationDirectory(),
);
task.updates.forEach(print);
task.onCompleted(() => task.openFile());

await Future.delayed(Duration(seconds: 3));
if (!task.isCompleted) {
  print('Download takes longer than three seconds.');
}

await task.waitUntilCompleted();

By using Streams rather than callbacks, it’s possible to leverage Dart’s strengths of async/await, applying stream transformations and support from the ecosystem. For example, one could easily build a Flutter widget like the following:

// inside a widget's State

DownloadTask task;

void _startDownload() {
  setState(() => task = DownloadTask.create(…));
}

Widget build(BuildContext context) {
  return Column(
    children: <Widget>[
      RaisedButton(onPressed: _startDownload, child: Text('Start download')),
      StreamBuilder<void>(
        stream: task?.updates ?? Stream.empty(),
        builder: (context, _) => Text('Progress: ${task?.progress}'),
      ),
    ],
  );
}

What do you think about this API?

[qq326646683]

same issue on Android, these works for me:

provider_paths.xml:

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <root-path
        name="root"
        path="." />
</paths>

[sqrg]

Sure, I can take a look on macOS. I don’t have much experience nor knowledge, but I’ll take a look