Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.2k views
in Technique[技术] by (71.8m points)

dart - Flutter Isolate vs Future

I might have the wrong idea of Isolate and Future. Please help me to clear it up. Here is my understanding of both subjects.

Isolate: Isolates run code in its own event loop, and each event may run smaller tasks in a nested microtask queue.

Future: A Future is used to represent a potential value, or error, that will be available at some time in the future.

My confusions are:

  1. The doc says Isolate has it own loop? I feel like having its own event queue makes more sense to me, am I wrong?

  2. Is future running asynchronously on the main Isolate? I'm assuming future task actually got placed at the end of event queue so if it will be execute by loop in the future. Correct me if I'm wrong.

  3. Why use Isolate when there is future? I saw some examples using Isolate for some heavy task instead of Future. But why? It only makes sense to me when future execute asynchronously on the main isolate queue.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

A Future is a handle that allows you to get notified when async execution is completed. Async execution uses the event queue and code is executed concurrently within the same thread.

https://webdev.dartlang.org/articles/performance/event-loop

Dart code is by default executed in the root isolate.

You can start up additional isolates that usually run on another thread. An isolate can be either loaded from the same Dart code the root isolate was started with (with a different entry-point than main() https://api.dartlang.org/stable/2.0.0/dart-isolate/Isolate/spawn.html) or with different Dart code (loaded from some Dart file or URL https://api.dartlang.org/stable/2.0.0/dart-isolate/Isolate/spawnUri.html).

Isolates don't share any state and can only communicate using message passing (SendPort/ReceivePort). Each isolate has its own event queue.

https://webdev.dartlang.org/articles/performance/event-loop


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...