Support multiple attachments on Android

[geraintwhite]

Fixes #153.

I've tested this in my app using my patch via patch-package but haven't tested it properly standalone.

It uses FileProvider so might need to include some of #127.

Please can someone else test it too to make sure there's nothing else missing in this implementation?

[chirag04]

@Relax594

[Relax594]

Instant crash on first run
Couldn't find meta-data for provider with authority de...provider

what am i missing?

EDIT: OK got it running. Please add the changes made in
android/src/main/AndroidManifest.xml
and
android/src/main/res/xml/provider_paths.xml
in #127 to this PR.

[geraintwhite]

I've implemented the FileProvider the way https://github.com/react-native-community/react-native-share does it so it will work if the app has its own FileProvider implementation (otherwise the manifest merger will fail on build).

[Relax594]

Even better, good catch.

The only thing im not quite sure about is
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Shouldn't this be up to the user instead of having it inside the lib?

[geraintwhite]

True, I only added it to mimic RNShare's implementation - I assume it would work without it?

[Relax594]

It does. If the user needs it however, its up to him to add the permission into the app's manifest. If you remove the permission from your commit, i think we're good to go.

[geraintwhite]

Should we use androidx.core.content.FileProvider instead of android.support.v4.content.FileProvider?

[Relax594]

Does not make a big difference right now but looking into the future it might be a good decision to do that, yes.

[geraintwhite]

@Relax594 all done!

[Relax594]

Thank you!

ping @chirag04 LGTM.

[chirag04]

awesome! appreciate your contributions 🙌