Read data from an other thread

[JM-dQ]

Hello, I'm learning how to use Druid and I can't find a way of reading the app data from an external thread. I'm looking for something like let data_reader = launcher.get_external_reader(); let data: AppData = data_reader.get_data().

Thanks for your time.

[xStrom]

There is no convenient way to directly read data from another thread. What you could do though is send a Command when the need arises, using ExtEventSink. Then on the main thread you will receive this Command and also have access to the app data. The Command payload can contain info you need on what exactly needs to happen. If the external thread needs some data back too, then you need another mechanism on top. For example a channel - where you send the Sender with the Command and listen with the Receiver on the other thread until the main thread handles the Command, processes the data, and sends the results back via the channel.

[ratmice]

IIRC when I was writing https://github.com/ratmice/neewerctl/blob/main/src/main.rs it uses the add_idle_callback rather than submit_command. Which is a bit uglier, and I forget exactly why, but there was some reason (some trait bounds that could not be satisfied with the Command approach, I believe).

There are examples of both these approaches in the repository
https://github.com/linebender/druid/blob/master/druid/examples/blocking_function.rs
https://github.com/linebender/druid/blob/master/druid/examples/async_event.rs

[JM-dQ]

Alr I'll try that thanks for the response.