Need to share drawables between different apps from different programmers

Question

I am attempting to create a free, configurable version of my EGMaps Android app which anyone can use to easily create their own map-based apps. The goal is to provide a framework so people with little programming knowledge can just fill in blanks, provide their data, and have it work.

There are two apps involved:

App #1 (EGMaps) does pretty much all the work. It needs access to data provided, or pointed to, by other App #2. I'm the only one working on this one.

App #2 will be created by multiple, maybe lots of other people, all with different app signatures. This is a very small, simple app which does very little other than passing data to EGMaps. I'll be providing source code and instructions on what to fill in. The other programmers can either use it directly, or modify it however they want for their app, which will then eventually call EGMaps.

App #2 needs to pass a lot of data like GPS coordinates, GPS tracks, marker locations, etc, which it's already doing. It also needs to pass an unknown, but potentially large number of small drawables. Due to space considerations, I'd prefer to use the drawables directly from the calling app, rather than copying them over or downloading and storing them inside of EGMaps. These drawables will eventually be Google Maps Marker icons.

Since the apps are written by different programmers, the app signatures are different, so setting the same user ID doesn't help.

This is as close as I've come:

iconString=callingPackage+":drawable/"+iconName;
iconValue=getResources().getIdentifier(iconString, "drawable", null);

callingPackage = name of calling app (ie: App #2). I have verified this is correct.

iconName = name of icon, as found in the drawable resources.

Without the callingPackage part, and with the drawables saved directly in the app, this works fine. It's just accessing the external drawable that doesn't work. iconValue always returns 0. I have also tried putting callingPackage into the third parameter of getIdentifier, with and without adding it to iconString, but that didn't make any difference.

Is there any way to directly (or indirectly, I suppose) access these drawables from the calling app without actually copying them from somewhere?

Answer 1

I would have expected getResources().getIdentifier(iconName, "drawable", callingPackage) to have worked, assuming that callingPackage is an actual package name.

You can try createPackageContext() and calling getResources() on it to get a Resources object referencing the other package.