How to share split APKs created while using instant-run, within Android itself?

Question

Background

I have an app (here) that, among other features, allows to share APK files.

In order to do so, it reaches the file by accessing the path of packageInfo.applicationInfo.sourceDir (docs link here), and just shares the file (using ContentProvider when needed, as I've used here).

The problem

This works fine in most cases, especially when installing APK files from either the Play Store or from a standalone APK file, but when I install an app using Android-Studio itself, I see multiple APK files on this path, and none of them are valid ones that can be installed and run without any issues.

Here's a screenshot of the content of this folder, after trying out a sample from "Alerter" github repo :

I'm not sure when this issue has started, but it does occur at least on my Nexus 5x with Android 7.1.2. Maybe even before.

What I've found

This seems to be caused only from the fact that instant run is enabled on the IDE, so that it could help updating the app without the need to re-build it all together :

After disabling it, I can see that there is a single APK, just as it used to be in the past:

You can see the difference in file size between the correct APK and the split one.

Also, it seems that there is an API to get the paths to all of the splited APKs:

https://developer.android.com/reference/android/content/pm/ApplicationInfo.html#splitPublicSourceDirs

The question

What should be the easiest way to share an APK that got to be split into multiple ones ?

Is it really needed to somehow merge them?

It seems it is possible according to the docs :

Full paths to zero or more split APKs that, when combined with the base APK defined in sourceDir, form a complete application.

But what's the correct way to do it, and is there a fast and efficient way to do it? Maybe without really creating a file?

Is there maybe an API to get a merged APK out of all the split ones? Or maybe such an APK already exist anyway in some other path, and there is no need for merging?

EDIT: just noticed that all third party apps that I've tried are supposed to share an installed app's APK fail to do so in this case.

Answer 1

I am the tech lead @Google for the Android Gradle Plugin, let me try to answer your question assuming I understand your use case.

First, some users mentioned you should not share your InstantRun enabled build and they are correct. The Instant Run builds on an application is highly customized for the current device/emulator image you are deploying to. So basically, say you generate an IR enabled build of your app for a particular device running 21, it will fail miserably if you try to use those exact same APKs on say a device running 23. I can go into much deeper explanation if necessary but suffice to say that we generate byte codes customized on the APIs found in android.jar (which is of course version specific).

So I do not think that sharing those APKs make sense, you should either use a IR disabled build or a release build.

Now for some details, each slice APK contains 1+ dex file(s), so in theory, nothing prevents you from unziping all those slice APKs, take all the dex files and stuff them back into the base.apk/rezip/resign and it should just work. However, it will still be an IR enabled application so it will start the small server to listen to IDE requests, etc, etc... I cannot imagine a good reason for doing this.

Hope this helps.