fix(android,build): load Android Gradle Plugin conditionally

[SaeedZhiany]

• Load Android Gradle Plugin conditionally

This wraps the Android Gradle plugin dependency in the buildscripts section of android/build.gradle in a conditional:

if (project == rootProject) {
    // ... (dependency here)
}

The Android Gradle plugin is only required when opening the project stand-alone, not when it is included as a dependency. By doing this, the project opens correctly in Android Studio, and it can also be consumed as a native module dependency from an application project without affecting the app project (avoiding unnecessary downloads/conflicts/etc).

for more info, you can refer to this thread and especially this comment.

• get project default ext configs from the root project

[Salakar]

Hey @SaeedZhiany

Thanks for this, am happy to merge the conditional logic for the gradle plugin.

Could you remove the safeExtGet stuff though - its not required as this functionality is already supported through https://github.com/invertase/react-native-gradle-plugin :

I can do a release with this in soon after its ready to merge

[SaeedZhiany]

Hey @Salakar

Oh, I didn't know that, I'll revert it.

do you want to keep buildToolVersion up to date at version 29.0.2? I know it's commented but it's worth keeping it updated.

[Salakar]

do you want to keep buildToolVersion up to date at version 29.0.2? I know it's commented but it's worth keeping it updated.

Ok lets keep it on the latest 👍

[SaeedZhiany]

It's done.

[claassistantio]

All committers have signed the CLA.

[mikehardy]

I love these PRs, slowly de-duplicating the gradle runtimes and eventually my react-native builds will stop downloading new gradles from random modules while building...

[Salakar]

It's done.

Awesome, thank you! Just the CLA left and I'll sort a release

[SaeedZhiany]

Just the CLA left and I'll sort a release

It's also done.

[Salakar]

v0.0.4 up with this, thank you 🎉