Sign and upload compiled apk to Github releases automatically using Travis CI

.travis.yml

language: android
android:
  components:
    # Uncomment the lines below if you want to
    # use the latest revision of Android SDK Tools
    - platform-tools
    - tools

    # The BuildTools version used by your project
    - build-tools-22.0.0

    # The SDK version used to compile your project
    - android-22

    # Additional components
    - extra-google-google_play_services
    - extra-google-m2repository
    - extra-android-m2repository

    # Specify at least one system image,
    # if you need to run emulator(s) during your tests
    # - sys-img-armeabi-v7a-android-19
    # - sys-img-x86-android-17

script: ./gradlew build

before_install:
  - sudo apt-get update -qq
  - sudo apt-get install -y python2.7

after_success: ./scripts/travis_upload_release_to_github.py

signing.gradle

/*
 * Twidere - Twitter client for Android
 *
 *  Copyright (C) 2012-2015 Mariotaku Lee <[email protected]>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
apply plugin: 'com.android.application'

/**
 * Gradle script for signing applications
 * Just apply this script to your application build.gradle file.
 * DON'T FORGET TO IGNORE signing.properties FROM YOUR VERSION CONTROL!!!
 *
 * @author Mariotaku Lee <[email protected]>
 */

android {

    signingConfigs {
        debug {
            File signingPropFile = rootProject.file('signing.properties')
            if (signingPropFile.exists()) {
                Properties signingProp = new Properties()
                signingProp.load(signingPropFile.newDataInputStream())
                storeFile file(signingProp.get("debug.storeFile"))
                storePassword signingProp.get("debug.storePassword")
                keyAlias signingProp.get("debug.keyAlias")
                keyPassword signingProp.get("debug.keyPassword")
            } else if (System.getenv('DEBUG_KEYSTORE_BASE64') != null) {
                storeFile decodeKeyStoreFileFromBase64Env('DEBUG_KEYSTORE_BASE64')
                storePassword System.getenv('DEBUG_KEYSTORE_PASSWORD')
                keyAlias System.getenv('DEBUG_KEYSTORE_KEY_ALIAS')
                keyPassword System.getenv('DEBUG_KEYSTORE_KEY_PASSWORD')
            }
        }
        release {
            File signingPropFile = rootProject.file('signing.properties')
            if (signingPropFile.exists()) {
                Properties signingProp = new Properties()
                signingProp.load(signingPropFile.newDataInputStream())
                storeFile file(signingProp.get("release.storeFile"))
                storePassword signingProp.get("release.storePassword")
                keyAlias signingProp.get("release.keyAlias")
                keyPassword signingProp.get("release.keyPassword")
            } else if (System.getenv('RELEASE_KEYSTORE_BASE64') != null) {
                storeFile decodeKeyStoreFileFromBase64Env('RELEASE_KEYSTORE_BASE64')
                storePassword System.getenv('RELEASE_KEYSTORE_PASSWORD')
                keyAlias System.getenv('RELEASE_KEYSTORE_KEY_ALIAS')
                keyPassword System.getenv('RELEASE_KEYSTORE_KEY_PASSWORD')
            }
        }
    }
    buildTypes {
        debug {
            if (rootProject.file('signing.properties').exists()
                    || System.getenv('DEBUG_KEYSTORE_BASE64') != null) {
                signingConfig signingConfigs.debug
            }
        }
        release {
            if (rootProject.file('signing.properties').exists()
                    || System.getenv('RELEASE_KEYSTORE_BASE64') != null) {
                signingConfig signingConfigs.release
            }
        }
    }

}

def decodeKeyStoreFileFromBase64Env(String name) {
    String keyStoreBase64 = System.getenv(name)
    if (keyStoreBase64 == null) return null
    File tempKeyStoreFile = File.createTempFile("tmp_ks_", ".jks", File.createTempDir())
    FileOutputStream fos = null
    try {
        fos = new FileOutputStream(tempKeyStoreFile)
        fos.write(keyStoreBase64.decodeBase64())
        fos.flush()
    } finally {
        if (fos != null) {
            fos.close()
        }
    }
    return tempKeyStoreFile
}

signing.properties

release.storeFile=/path/to/your/keystore/file.jks
release.storePassword=p455w0rd
release.keyAlias=awesome
release.keyPassword=53cr3t

debug.storeFile=/path/to/your/keystore/file.jks
debug.storePassword=p455w0rd
debug.keyAlias=awesome
debug.keyPassword=53cr3t

travis_upload_release_to_github.py

#!/usr/bin/env python2
# -*- coding: utf-8 -*-
from __future__ import print_function

import os
import sys
import httplib
import urllib
import urlparse
import json
import fnmatch
import re
from os import getenv
from subprocess import check_output
from subprocess import CalledProcessError

__author__ = 'mariotaku'
git_https_url_prefix = 'https://github.com/'
git_ssh_url_prefix = '[email protected]:'
git_git_url_prefix = 'git://github.com/'
git_file_suffix = '.git'
github_header_accept = 'application/vnd.github.v3+json'
github_header_user_agent = 'TravisUploader/0.1'

DEVNULL = open(os.devnull, 'w')
repo_url = None

try:
    repo_url = check_output(['git', 'config', '--get', 'remote.origin.url']).splitlines()[0]
except CalledProcessError:
    print('No remote url for this project, abort')
    exit(0)

user_repo_name = None
if repo_url.startswith(git_ssh_url_prefix):
    user_repo_name = repo_url[len(git_ssh_url_prefix):]
elif repo_url.startswith(git_https_url_prefix):
    user_repo_name = repo_url[len(git_https_url_prefix):]
elif repo_url.startswith(git_git_url_prefix):
    user_repo_name = repo_url[len(git_git_url_prefix):]

if not user_repo_name:
    print('Not a github repo (%s), abort' % repo_url, file=sys.stderr)
    exit(0)

if user_repo_name.endswith(git_file_suffix):
    user_repo_name = user_repo_name[:-len(git_file_suffix)]

current_tag = None
current_tag_body = None
try:
    current_tag = check_output(['git', 'describe', '--tags', '--exact-match', '--abbrev=0'],
                               stderr=DEVNULL).splitlines()[0]
except CalledProcessError:
    print('This commit doesn\'t have tag, abort', file=sys.stderr)
    exit(0)
try:
    current_tag_body = '\n'.join(
        check_output(['git', 'show', '-s', '--format=%b', current_tag], stderr=DEVNULL).splitlines()[2:])
except CalledProcessError:
    current_tag_body = "Automatic upload for version %s" % current_tag

github_access_token = getenv('GITHUB_ACCESS_TOKEN')

if not github_access_token:
    print('No access token given, abort', file=sys.stderr)
    exit(0)

github_authorization_header = "token %s" % github_access_token

print('Creating release for tag %s' % current_tag)

req_headers = {'Accept': github_header_accept}

conn = httplib.HTTPSConnection('api.github.com')
conn.request('POST', '/repos/%s/releases' % user_repo_name,
             body=json.dumps({
                 'tag_name': current_tag,
                 'name': "Version %s" % current_tag,
                 'body': current_tag_body
             }),
             headers={
                 'Accept': github_header_accept,
                 'Authorization': github_authorization_header,
                 'Content-Type': 'application/json',
                 'User-Agent': github_header_user_agent
             })
response = conn.getresponse()
if response.status == 422:
    conn = httplib.HTTPSConnection('api.github.com')
    conn.request('GET', '/repos/%s/releases/tags/%s' % (user_repo_name, current_tag),
                 headers={
                     'Accept': github_header_accept,
                     'Authorization': github_authorization_header,
                     'User-Agent': github_header_user_agent
                 })
    response = conn.getresponse()

if response.status not in range(200, 204):
    print('Unable to create or get release, abort', file=sys.stderr)
    exit(0)

response_values = json.loads(response.read())

upload_url = urlparse.urlparse(re.sub('\{\?([\w\d_\-]+)\}', '', response_values['upload_url']))
for root, dirnames, filenames in os.walk(os.getcwd()):
    for filename in fnmatch.filter(filenames, '*-release.apk'):
        conn = httplib.HTTPSConnection(upload_url.hostname)
        conn.request('POST', "%s?%s" % (upload_url.path, urllib.urlencode({'name': filename})),
                     body=open(os.path.join(root, filename), 'r'),
                     headers={
                         'Accept': github_header_accept,
                         'Authorization': github_authorization_header,
                         'Content-Type': 'application/json',
                         'User-Agent': github_header_user_agent
                     })
        print("Upload %s returned %d" % (filename, conn.getresponse().status))

Nice gist.
But why you dont use the release feature of travis ?