[expo-blur][Android] Add support for BlurView on Android

[behenate]

Why

There was no support for BlurView on android. Instead of blurring the view would just set the background color to semitransparent.

How

Using BlurView library and Modules API added blur support for Android. Default prop settings match it quite closely with the iOS version.

Test Plan

Tested on Android emulators (API 33 and 28), and a physical device (API 31). Also compared the look of the blur on android emulator to the iOS simulator.

[fobos531]

This is a great idea if we want to support as many Android versions as possible. However, this is a 3rd party library - any thoughts on using the built-in Android API for this? https://source.android.com/docs/core/display/window-blurs The downside to the built-in API is that its only available from Android 12 while I'm sure the 3rd party package supports lower Android versions as well.

I think both using the 3rd party library and 1st party Android support has its up and downsides. Maybe we could use BlurView on Android < 12 and use the built-in support on Android >= 12, provided there is a way to achieve API parity across the two libraries and all android versions? Thoughts?

[behenate]

@fobos531 It seems like using the built-in API would require us to create a separate activity for blurring which is not really viable. The 3rd party library is using RenderEffect.createBlurEffect from API 31 though.

[ArtKullashi]

I'm so glad to see this pr and hope it gets merged. So long as it looks similar to the ios blur, I don't think it should matter if you use the built-in API or the library.

[aleqsio]

I hope we'll land this, using a lot of blur views in the appjs app ❤️
Curious how the performance of the android implementation looks like without platform support, hope it's fairly fast 🙏

[fobos531]

I hope we'll land this, using a lot of blur views in the appjs app ❤️ Curious how the performance of the android implementation looks like without platform support, hope it's fairly fast 🙏

Same! It would be awesome if it can be shipped as a "post-release addition" of SDK 48, but if its not feasible and has to wait until SDK 49, completely understandable! 👍

[Nodonisko]

Great job, we will use this ASAP in our app!

[lukmccall]

I've talked with @tsapete - we decided it will be better to rename that. Let's call it androidBlurReductionFactor instead.

[tsapeta]

Fyi: I've been convinced to keep blurReductionFactor as this is not common across our APIs to use platform names in such cases and also that this prop is not going to be used very often because the default behavior is good enough in most cases.

[eeshankeni]

This update makes Android lag uncontrollably on my OnePlus 6. But on other Android devices, it seems to work fine.
Here is a recording before and after setting intensity to 0
https://imgur.com/a/DiKVmbs

[tsapeta]

@eeshankeni Can you open an issue with a minimal reproducible example? Repro would help us fix it faster 🙂

[RGarrido03]

Hi! I'm trying to use the 12.3.0 version of expo-blur because of this feature. However, when running and compiling to Android, the Expo server tells me that The native view manager required by name (ExpoBlurView) from NativeViewManagerAdapter isn't exported by expo-modules-core. Views of this type may not render correctly. Exported view managers: [ExpoLinearGradient, ExpoVideoView, ExpoBarCodeScanner, ExponentGLView, ExpoImage, ExponentCamera].

I guess this happens due to the fact that I'm using the latest stable version of Expo (i.e., the 48.0.15 one), so how can I sort this thing out? Since version 49 beta isn't still available, is there any way to compile Expo from the source? Thanks.

[tsapeta]

Hey @RGarrido03, could you please open a new issue instead of reporting it on the PR? We'll also need a minimal reproducible example, so we can test it out ourselves.

Generally this feature should work well with all 48.* versions, except Expo Go that we don't update in between of SDK releases. If you're using bare workflow or development builds then there should be no issue like this. In the latter case, you'll need to rebuild the app as it contains native changes. If that doesn't solve the issue, please open a new issue as I said at the beginning.