Automate Releases Using Travis CI and Github Releases

Add Travis CI config with github release support.
This should upload artifacts to GitHub release after
a tag is pushed to the repo. A way to automate the release.
It also makes builds on every branch that gets a commit push.

Add information on how to make a release for the project. This
is a separate markdown file detailing the procedure.

.travis.yml

@@ -0,0 +1,28 @@
+language: android
+android:
+  components:
+    - tools
+    - platform-tools
+    # Note that the tools section appears twice on purpose as it’s required to get the newest Android SDK tools.
+    # See: https://docs.travis-ci.com/user/languages/android/#Overview
+    - tools
+    - build-tools-27.0.2
+    - build-tools-26.0.2
+    - android-27
+    - android-26
+before_cache:
+  - rm -f $HOME/.gradle/caches/modules-2/modules-2.lock
+cache:
+  directories:
+    - $HOME/.gradle/caches/
+    - $HOME/.gradle/wrapper/
+before_script:
+  - export VERSION_TO_BUILD="$TRAVIS_TAG"
+script: ./gradlew clean build
+deploy:
+  provider: releases
+  api_key: $GITHUB_OAUTH_TOKEN
+  file: usbserial/build/outputs/aar/usbserial-${VERSION_TO_BUILD}-release.aar
+  skip_cleanup: true
+  on:
+    tags: true

README.md

@@ -1,4 +1,4 @@
-UsbSerial [![](https://jitpack.io/v/felHR85/UsbSerial.svg)](https://jitpack.io/#felHR85/UsbSerial) [![AndroidArsenal](https://img.shields.io/badge/Android%20Arsenal-UsbSerial-green.svg?style=true)](https://android-arsenal.com/details/1/4162) [![Join the chat at https://gitter.im/UsbSerial/Lobby](https://badges.gitter.im/UsbSerial/Lobby.svg)](https://gitter.im/UsbSerial/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+UsbSerial [![Build Status](https://travis-ci.org/felHR85/UsbSerial.svg?branch=master)](https://travis-ci.org/felHR85/UsbSerial) [![](https://jitpack.io/v/felHR85/UsbSerial.svg)](https://jitpack.io/#felHR85/UsbSerial) [![AndroidArsenal](https://img.shields.io/badge/Android%20Arsenal-UsbSerial-green.svg?style=true)](https://android-arsenal.com/details/1/4162) [![Join the chat at https://gitter.im/UsbSerial/Lobby](https://badges.gitter.im/UsbSerial/Lobby.svg)](https://gitter.im/UsbSerial/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) 
 =========
 Usb serial controller for Android. For more information, there is [a more complete description](http://felhr85.net/2014/11/11/usbserial-a-serial-port-driver-library-for-android-v2-0/).
 

RELEASING.md

@@ -0,0 +1,16 @@
+Releasing
+========
+
+ 1. Change the `VERSION_NAME` value in `gradle.properties` to the version number to be released.
+ 2. Update the `README.md` with the new version.
+ 3. `./gradlew clean build`
+ 4. `git commit -am "Prepare for release X.Y.Z."` (where X.Y.Z is the new version)
+ 5. `git tag -a X.Y.Z -m "Version X.Y.Z"` -m "Changelog message 1" - m "Changelog message 2" -m "Changelog message 3"
+ 6. `git push && git push --tags`
+
+ *Note:* To get the changelog messages from the commit history, issue
+
+ ```shell
+ git log "$(git tag | tail -n2 | head -n1)..$(git tag | tail -n1)" --oneline --invert-grep --grep="Merge pull request" --grep="Prepare for release" | cut -d' ' -f2- | sed -E -e 's/^/-m "/' | sed -E -e 's/$/"/'
+ ```
+

gradle.properties

@@ -1,4 +1,4 @@
-VERSION_NAME=1.0
+VERSION_NAME=4.5.1
 VERSION_CODE=1
 ANDROID_BUILD_MIN_SDK_VERSION=12
 ANDROID_BUILD_TARGET_SDK_VERSION=27

usbserial/build.gradle

@@ -1,9 +1,11 @@
 apply plugin: 'com.android.library'
 
+def artifact = "usbserial.jar"
+
 android {
 
     group = 'com.felhr.usbserial'
-    version = '1.0.0'
+    version = project.VERSION_NAME
 
     compileSdkVersion Integer.parseInt(project.ANDROID_BUILD_SDK_VERSION)
 
@@ -16,19 +18,20 @@ android {
     defaultConfig {
         minSdkVersion Integer.parseInt(project.ANDROID_BUILD_MIN_SDK_VERSION)
         targetSdkVersion Integer.parseInt(project.ANDROID_BUILD_TARGET_SDK_VERSION)
+        archivesBaseName = "${project.name}-${project.VERSION_NAME}"
     }
 
     //noinspection GroovyAssignabilityCheck
-    task deleteJar(type: org.gradle.api.tasks.Delete) {
-        delete 'eclipse_lib/usbserial.jar'
+    task deleteJar(type: Delete) {
+        delete "eclipse_lib/${artifact}"
     }
 
     //noinspection GroovyAssignabilityCheck
     task createJar(type: org.gradle.api.tasks.Copy) {
         from('build/intermediates/bundles/release/')
         into('eclipse_lib/')
         include('classes.jar')
-        rename('classes.jar', 'usbserial.jar')
+        rename('classes.jar', artifact)
     }
 
     createJar.dependsOn(deleteJar, build)