Where to I place the OBB file to test Android Expansion Pack Files (OBB) on my Nexus 4?

Question

I'm trying to test the Expansion Pack Files (OBB) In Android following the guide here: http://developer.android.com/google/play/expansion-files.html

I'm in the step where I need to test my app on my Nexus 4.

I generated my .obb file with jobb and adb-pushed it in the device in this location:

/mnt/shell/emulated/0/Android/obb/my.package/main.1.my.package.obb

When the app run it doesn't find the file.

Method:

Helpers.doesFileExist(context, fileName, xf.mFileSize, false)

return false for my file.

I debugged and found out it is looking for the file in:

/storage/emulated/0/Android/obb/my.package/main.1.my.package.obb

Specifically this is the path returned by:

Helpers.generateSaveFileName(c, fileName)

The /storage/emulated/0, returned by Environment.getExternalStorageDirectory() doesn't exist browsing the device with adb shell.

But it DOES at runtime, inside the app, I also checked what it contains: it contains almost the same things I found in /mnt/shell/emulated/0, it contains the Android/obb dir, which is empty.

How I found out the path /mnt/shell/emulated/0/Android/obb/my.package/main.1.my.package.obb where I placed my obb file:

$ adb shell
$ ls -ld sdcard
lrwxrwxrwx root     root              2013-10-16 17:34 sdcard -> /storage/emulated/legacy
$ ls -ld /storage/emulated/legacy
lrwxrwxrwx root     root              2013-10-16 17:34 legacy -> /mnt/shell/emulated/0

And inside that I already found the Android/obb directory, empty.

So the question is: where should I put my obb file for it to be in the right position at runtime?

I did everything said there:

• created a draft application in the Market to get the public key

• generated a random array of 20 byte (salt)

• integrated play_licensing/library and play_apk_expansion/download_library

• wrote my Service / Receiver

• did the check using the Helpers etc.. exactly like the documentation say.

I suppose everything works but I can't just yet release on Play Store! I need to test locally and I'll have the need to change my obb file pretty often in this initial phase of development.

I can't test on the Emulator because I use 3D and device camera.

Answer 1

Since Android 4.2 multi users support have been added.

To support that Android mount an emulated disk for each users acting as a sandbox layer around the actual filesystem: this let Android handle gracefully either sharing of files between users either personal files.

Long story short:

/storage/emulated

is the emulated filesystem.

if you enter that directory from adb shell you may see a

/storage/emulated/obb

directory. Sometimes it doesn't show up, for some reason (see below for what to do if this happen)

It's not in /Android/obb but that's the right directory where to place your app package / obb file!

If you don't see that directory try looking in:

/mnt/shell/emulated/obb

You should be able to put your file there.

It will be correctly picked up at runtime ending at the

/storage/emulated/0/Android/obb/my.package/main.1.my.package.obb

path.

I think the Android documentation should explain this.

(I answer my own question because I found out how to solve it while writing it.)