在ConnectionState.done之后使用多个流重新启动StreamBuilder [英] Restart StreamBuilder with multiple streams after ConnectionState.done
问题描述
当您要在StreamBuilder中使用多个流时,重新启动StreamBuilder以使用下一个流时,有什么好方法?
What's a good way when you want to use multiple streams in a StreamBuilder, to restart StreamBuilder to use the next stream?
现在,我正在通过在标志(_streamCompleted)上使用setState检查流是否已完成。
Right now, I am checking if the stream is completed by using setState on a flag (_streamCompleted).
但是我想知道在ConnectionState.done被触发后是否可以重用StreamBuilder。
But I was wondering if it's possible to reuse the StreamBuilder after ConnectionState.done is fired.
Stream donwloadStream = response.stream.map(processDownload);
...
StreamBuilder(
stream: _streamIndex == null ? null : streams[_streamIndex].stream,
builder: (context, snapshot) {
if (ConnectionState.done) {
// How do I switch to the next stream here ???
}
这是我检查是否完成的方式:
This is how I am checking if completed:
double processDownload(List<int> chunk) {
bytes.addAll(chunk);
cnt = bytes.length;
double progress = cnt / streams[_streamIndex].contentLength;
if (cnt / streams[_streamIndex].contentLength == 1) {
setState(() {
_streamCompleted = true;
_streamIndex++;
});
}
return progress;
}
我也尝试过使用CombineLatestStream,但无法获取流要开始触发,ConnectionState为空。
I have also tried using CombineLatestStream, but couldn't get the streams to start firing, ConnectionState is none.
StreamBuilder(
stream: _combinedStreams == null ? null : _combinedStreams,
setState(() {
_combinedStreams =
CombineLatestStream.list([streams[0].stream, streams[1].stream, streams[2].stream])
.asBroadcastStream();
});
_combinedStreams.listen((event) {});
推荐答案
只需使用两个流生成器。
Just use two stream builder.
StreamBuilder(
stream: _streamIndex == null ? null : streams[_streamIndex].stream,
builder: (context, snapshot) {
if (ConnectionState.done) {
StreamBuilder(
stream: _stream2 == null ? null : streams2.stream,
builder: (context, snapshot2) {...
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