Flutter：访问进程标准输出并流式传输到 StreamBuilder 小部件

Question

我希望能够使用 await Process.start() 启动进程并能够在进程执行期间访问标准输出并将输出发送到 StreamBuilder 小部件。

StreamBuilder 小部件

StreamBuilder(
          stream: snapshot.data,
          builder: (BuildContext context, AsyncSnapshot stream) {
            print('Connection State: ${stream.connectionState}');
            switch (stream.connectionState) {
              case ConnectionState.done:
                return SingleChildScrollView(
                    controller: controller,
                    reverse: true,
                    child: Text(
                      executionOutput,
                    ));
              default:
                executionOutput += '\n${stream.data}';
                return SingleChildScrollView(
                    controller: controller,
                    reverse: true,
                    child: Text(
                      executionOutput,
                    ));

这是我的流代码，我想每秒检查一次标准输出，直到进程完成

Stream getOutput() async* {
    var p = await Process.start('python.exe', ['streamData.py']);

    while (true) {
      await Future.delayed(Duration(seconds: 1));
      yield p.stdout.transform(utf8.decoder).toString();
    }
  }

Answer 1

使用yield*将流委托给另一个流。

import 'dart:convert';
import 'dart:io';

void main(List<String> args) {
  getOutput().listen(print);
}

Stream getOutput() async* {
  var p = await Process.start('tail', ['-f', '/path/to/log']);
  yield* p.stdout.transform(utf8.decoder);
}

Flutter：访问进程标准输出并流式传输到 StreamBuilder 小部件

Flutter: Access Process stdout and stream to StreamBuilder widget

process

dart

flutter