Refer android libraries correctly

.jar files should be referred with the lib-file tag as suggested in the docs .so files should be included in jniLibs directory inside platforms/android/app/src/main. Else they are not included and will not work.

Why propose this change?

Installing this plugin places both the .jar and the .so dependency files inside platforms/android/libs/ directory. This confuses cordova into thinking that the project's structure is actually an old eclise project and causes subsequent plugin installations to act accordingly and look for AndroidManifest.xml (and other configuration files) in the wrong place. This results in errors like:

Failed to install 'cordova-plugin-whitelist': Error: ENOENT: no such file or directory, open 'D:\Testing\masterTest\platforms\android\AndroidManifest.xml'
    at Error (native)
    at Object.fs.openSync (fs.js:640:18)
    at Object.fs.readFileSync (fs.js:508:33)
    at Object.parseElementtreeSync (D:\Testing\masterTest\platforms\android\cordova\node_modules\cordova-common\src\util\xml-helpers.js:180:27)
    at new AndroidManifest (D:\Testing\masterTest\platforms\android\cordova\lib\AndroidManifest.js:29:20)
    at AndroidProject.getPackageName (D:\Testing\masterTest\platforms\android\cordova\lib\AndroidProject.js:99:12)
    at Api.addPlugin (D:\Testing\masterTest\platforms\android\cordova\Api.js:223:57)
    at handleInstall (C:\Users\kerezov\AppData\Roaming\npm\node_modules\cordova\node_modules\cordova-lib\src\plugman\install.js:594:10)
    at C:\Users\kerezov\AppData\Roaming\npm\node_modules\cordova\node_modules\cordova-lib\src\plugman\install.js:357:28
    at _fulfilled (C:\Users\kerezov\AppData\Roaming\npm\node_modules\cordova\node_modules\cordova-lib\node_modules\q\q.js:787:54)
Failed to restore plugin "cordova-plugin-whitelist" from config.xml. You might need to try adding it again. Error: Error: ENOENT: no such file or directory, open 'D:\Testing\masterTest\platforms\android\AndroidManifest.xml'
--save flag or autosave detected

Why aren't both files referenced as `lib-file`?

The .so file isn't properly included in the result .apk if it is referenced as a lib-file. Even if the arch="device" tag is specified as suggested in the docs, the .so file still ends up in libs directory rather than jniLibs

Why reference the `.so` as a `resource-file` instead of a `source-file`?

In case the .so is referenced as a source-file it ends up in the root of platforms/android - namely at platforms/android/jniLibs/armeabi-v7a/libtensorflow_inference.so. What we actually want is for it to end up at platforms/android/app/src/main/jniLibs/armeabi-v7a/libtensorflow_inference.so in order for it to end up properly in the built .apk.

Further improvement

This .so library can actually be included inside a .jar and referenced as a lib-file. This is the way to move forward I think because that would alleviate cordova of trying to place the file in the correct directory and let the gradle build system handle it. An example of this can be seen in this sqlite plugin

The above has all been tested with cordova cli version 8.0.0 and cordova-android@~7.0.0 Ping @sheppard for thoughts about this

heigeo / cordova-plugin-tensorflow