buildscript {
    dependencies {
        ...
        classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.6'
        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.4.1'
    }
}

apply plugin: 'com.android.library'

ext {
    bintrayRepo = 'testMaven'
    bintrayName = 'mylib'

    publishedGroupId = 'com.hgDendi'
    libraryName = 'MyLib'
    artifact = 'mylib'

    libraryDescription = 'lib test demo'

    siteUrl = 'https://github.com/hgDendi/AndroidJCenterDemo'
    gitUrl = 'https://github.com/hgDendi/AndroidJCenterDemo.git'

    libraryVersion = '1.0.0'

    developerId = 'dendi'
    developerName = 'Dendi Chan'
    developerEmail = 'hg.dendi@gmail.com'

    licenseName = 'The MIT License'
    licenseUrl = 'https://rem.mit-license.org'
    allLicenses = ["MIT"]
}

...

apply from: 'https://raw.githubusercontent.com/hgDendi/AndroidJCenterDemo/master/bintray.gradle'
apply from: 'https://raw.githubusercontent.com/hgDendi/AndroidJCenterDemo/master/maveninstall.gradle'

bintray.user=[...]
bintray.apikey=[...]
bintray.gpg.password=[...]