[android] Adding Bintray Gradle plugin for artifact publishing

[langsmith]

Because of recent artifact publishing issues with Sonatype and CircleCI, this pr adds https://github.com/bintray/gradle-bintray-plugin so that we can publish Maps SDK for Android artifacts to Bintray. We can pass them on to Maven Central once in Bintray.

cc @mapbox/maps-android

[langsmith]

This pr is still a work in progress, but I think things are close to being done. I opened the pr for visibility

[langsmith]

Progress! After lots of tweaking, bintrayUpload finally successfully created https://bintray.com/mapbox/mapbox/mapbox-android-sdk . Not sure why https://bintray.com/mapbox/mapbox/mapbox-android-sdk#files is empty but at least we've moved forward on this. Yes, the 0.0.0 version can be deleted 😄

File issue seems to be related to the POM file setup:

[langsmith]

Seems that the error mentioned above is one that many others have seen

bintray/gradle-bintray-plugin#88

bintray/gradle-bintray-plugin#81

[langsmith]

MapboxGLAndroidSDK seems to be used by the Gradle Bintray plugin and set as the artifactId, rather than the artifactId value of mapbox-android-sdk which I set at https://github.com/mapbox/mapbox-gl-native/pull/13999/files#diff-e8814550c6b8959b69ba7bdabdd97566R25

Despite that, latest commit was able to create the aar and pom files and their signed .asc version.

The POM file goes to https://bintray.com/mapbox/mapbox/mapbox-android-sdk, however it's incomplete 😕 The POM generated by this branch is still missing some fields that the POM found at https://search.maven.org/artifact/com.mapbox.mapboxsdk/mapbox-android-sdk/7.2.0/aar has . Each dependency in the Bintray POM is missing the scope and exclusion fields, and I've yet to figure out why. The Bintray POM is also missing opening fields such as url, description, and developers. I set that info in gradle-bintray.gradle, so I'm not sure why it's not carrying over. Remedy is in this comment/thread?: novoda/bintray-release#19 (comment) ?

Bintray POM:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.mapbox.mapboxsdk</groupId>
  <artifactId>MapboxGLAndroidSDK</artifactId>
  <version>7.3.0-SNAPSHOT</version>
  <packaging>aar</packaging>
  <dependencies>
    <dependency>
      <groupId>com.mapbox.mapboxsdk</groupId>
      <artifactId>mapbox-sdk-turf</artifactId>
      <version>4.3.0</version>
    </dependency>
    <dependency>
      <groupId>com.android.support</groupId>
      <artifactId>appcompat-v7</artifactId>
      <version>27.1.1</version>
    </dependency>
    <dependency>
      <groupId>com.android.support</groupId>
      <artifactId>support-annotations</artifactId>
      <version>27.1.1</version>
    </dependency>
    <dependency>
      <groupId>com.android.support</groupId>
      <artifactId>support-fragment</artifactId>
      <version>27.1.1</version>
    </dependency>
    <dependency>
      <groupId>com.squareup.okhttp3</groupId>
      <artifactId>okhttp</artifactId>
      <version>3.12.0</version>
    </dependency>
    <dependency>
      <groupId>com.getkeepsafe.relinker</groupId>
      <artifactId>relinker</artifactId>
      <version>1.3.1</version>
    </dependency>
    <dependency>
      <groupId>com.mapbox.mapboxsdk</groupId>
      <artifactId>mapbox-android-telemetry</artifactId>
      <version>4.2.0</version>
    </dependency>
    <dependency>
      <groupId>com.mapbox.mapboxsdk</groupId>
      <artifactId>mapbox-sdk-geojson</artifactId>
      <version>4.3.0</version>
    </dependency>
    <dependency>
      <groupId>com.mapbox.mapboxsdk</groupId>
      <artifactId>mapbox-android-gestures</artifactId>
      <version>0.4.0</version>
    </dependency>
  </dependencies>
</project>

----Instructions if you'd like to try yourself------

Switch to this branch, cd to this repo's root folder on the command line, and then run make apackage to create the artifact files. Add BINTRAY_USER, BINTRAY_KEY, and GPG passphrase and their respective values to your gradle.properties file (e.g. BINTRAY_KEY=key). Another option is to just hardcode them (but don't commit/push them to Github!!!) in the user and key fields at the top of the bintray {} section of the gradle-bintray.gradle file (e.g. key = "key"). You can set passphrase in the gpg section at the bottom of the gradle-bintray.gradle file. Once the artifact creation process is done and you've set the bintray user/key, run make run-android-upload-to-bintray on the command line. You should see something similar to:

Still need to figure out:

1. why the POM isn't being filled out with all of the various information, which I set in the gradle-bintray.gradle file
2. finishing figuring out how to upload the files that are part of a Maps SDK release (javadoc.jar, sources.jar, etc.) https://search.maven.org/artifact/com.mapbox.mapboxsdk/mapbox-android-sdk/7.2.0/aar

3. why MapboxGLAndroidSDK is being filled into the POM file as artifactId. Related to 400 Response but Successful Upload bintray/gradle-bintray-plugin#81 (comment)?

[LukasPaczos]

Thanks for kicking this off @langsmith!

I've made some changes to resolve the Still need to figure out points. Key takeaways are:

• maven-publish plugin doesn't fill out POM files automatically, to tackle this, I've used this Gradle plugin which reduces the boilerplate of including the deps manually, however, the additional info like names and URLs still had to be added manually.
• Javadocs are generated as they were before and included in the artifact.
• Because of the improved POM file generation, we are actually going to ship dependencies with correct scopes (runtime/compile) and prevent leaks.

[LukasPaczos]

Since we are still waiting for the jCenter account to be opened in order to server SNAPSHOTs, 7a09e80 disables those builds for now, so that we can ship the alpha build without delaying further.