Android: arm64 support

[mortend]

The Play Store will require 64-bit support when uploading an APK beginning in August 2019. Start porting now to avoid surprises when the time comes. For more information, see this blog post.

See https://github.com/android-ndk/ndk/wiki/Changelog-r19

[AndrewEQ]

Ok, so what do we have to do practically?

Is this an NDK thing that we have to add to in gradle? By we, I mean @mortend via Uno 😄 ~ https://stackoverflow.com/a/54474417/2139770

[AndrewEQ]

I see there's an APK analyzer: https://developer.android.com/studio/build/apk-analyzer

[AndrewEQ]

Here's the android docs reference for telling gradle to build 64bit version of NDK libs: https://developer.android.com/distribute/best-practices/develop/64-bit#building_with_android_studio_or_gradle

[kusma]

I guess we need to build aarch64 versions of uno-base and other dependencies?

[mortend]

@kusma is correct. In addition we may have to generate both armv7 and arm64 code and include both in the app in order to not break support for older devices. This will almost double the time it takes to build though, at least on release builds...

[AndrewEQ]

Darn it, will this also inflate app size too?

I found this attribute(https://developer.android.com/reference/android/R.attr.html#extractNativeLibs) we can add to the <application> as false in the manifest to prevent the copying out of the native libs from the APK to the filesystem that can save us some space.

[mortend]

I briefly read something a long time ago where (if I remember correctly) it sounded like the Play Store can split the APK and install only one part based on what device the user have. If this is how it works it won't inflate app sizes for end-users downloading apps, but it will inflate the size of the master APK uploaded to Play Store.

[ichan-mb]

Yeah... Google Play now has shown warning messages about this, as mention it in a forum post here