How to record a video of a Jetpack Compose @Composable function without blocking UI thread?

466 views Asked by Kolay At 19 October 2023 at 20:32

Context

I have a Jetpack Compose @Composable function that has a AndroidView (Camera previewview) and a Canvas that I draw on.

Here's a very simplified version of my code:

@Composable
fun ExerciseCanvasView(...) {
  Box(modifier = Modifier.fillMaxSize()) {
    AndroidView(...)
    Canvas(...)
  }
}

Basically, I want to record a video of this function and save it into a file (video.mp4).

MediaProjection. I tried MediaProjection but is not what I want. It records the whole screen and I dont really need that and it might record sensitive info.
Drawing a composeview to a canvas to a bitmap. I have tried this also, but the drawing has to be done in the Main UI Thread (this question) and this blocks the Main UI Thread, rendering it unusable.
Some other deprecated shenanigans that chatgpt recommended that dont work at all.

For now, I dont care if even i have to save captures of the Composable and then encode them to a video or anything, I cant even make that to work...

Has anyone faced a similar issue and found a solution to record only this specific @Composable without blocking the UI thread?