Feature request: Add as an Android screen saver

[adamhotep]

The Pixel Weather app can display weather info on the lock screen when charging as a "screen saver" and I'd love to see this app similarly introduce a screensaver function as well. I know it's possible with 100% F/OSS since XScreenSaver does it (though not for weather).

[PranshulGG]

@adamhotep cool idea! Not totally sure how I could pull it off with Flutter, but I can give it a try.

The Pixel Weather app can display weather info on the lock screen when charging as a "screen saver"

From what I know, it’s actually the Pixel system that provides those screensavers, not sure if the Weather app itself handles it directly

[deminearchiver]

From what I know, it’s actually the Pixel system that provides those screensavers, not sure if the Weather app itself handles it directly

Hello! I am a Flutter developer and I do not even use screensavers, but after a quick search I've found that an API might exist: android.service.dreams.DreamService.

I have no idea how to test a screensaver with an emulator so even a proof-of-concept is hard to produce. Please let me know what you think of implementing this service.

[deminearchiver]

I have found some Android apps using the aforementioned service, installed them, and, indeed, I found new screensaver options in system settings on latest stable Android version (16 QPR1). Also forgot that it's possible to preview screensavers so testing might not be that big of a problem after all.

Now the real problem is inflating the Flutter UI in the DreamService. The main idea would be to create a FlutterView and pass it to setContentView(View).

Implementing a FlutterView requires a bit too much work: https://github.com/flutter/samples/tree/main/add_to_app/android_view. I will try to spin up a draft proof-of-concept PR, stay tuned.

[adamhotep]

Thanks for the attention. It's too bad this is nontrivial.

There might be some clues in Zygo's read-only clone* of XScreenSaver for Android (such as in Daydream.java), but translating that to Flutter may be nontrivial. (*: JWZ doesn't appear to have a public code repo for XSS, so this is a clone built from his releases.)

The only Flutter+DreamService reference I could find was flutter/flutter#63274, which was closed as being better served on the forums, but it doesn't appear the question was ever asked there.

Would it make sense to simply render a full-screen image/video and set that as the screen saver? Tapping on Pixel Weather in screen saver mode simply prompts for a fingerprint and then opens the app (you don't want to enable too much on a locked screen).

[deminearchiver]

There might be some clues in Zygo's read-only clone* of XScreenSaver for Android (such as in Daydream.java), but translating that to Flutter may be nontrivial. (*: JWZ doesn't appear to have a public code repo for XSS, so this is a clone built from his releases.)

Would it make sense to simply render a full-screen image/video and set that as the screen saver? Tapping on Pixel Weather in screen saver mode simply prompts for a fingerprint and then opens the app (you don't want to enable too much on a locked screen).

I've already made a proof-of-concept implementation in #691 (in case you didn't notice that). The Flutter app can already be rendered into the screen saver activity using DreamService, and it even receives pointer events! I stopped working on the PR because I really want to put all of this functionality into a Flutter plugin so it can be easily integrated in different projects. Also, I haven't really tested Flutter's platform functionality (e.g. reading asset bundles, calling some platform APIs which require an Activity, etc.).

[deminearchiver]

@PranshulGG do you think I should still give this issue a go? I've been heavily investing my time into learning how to reliably create Android plugins with JNI FFI, but I doubt it would help here, since the problem is that we have to essentially emulate a nonexistent FlutterActivity with all the platform communication.

[PranshulGG]

@deminearchiver Yeah, I think you should give it a shot. I’m going to be out for the next week, so I won’t be able to help in the meantime, but I’ll review the PR when I’m back if you want to go for it

[deminearchiver]

@PranshulGG I'm also going out for the next week, so I probably won't be able to continue working during the mentioned period.