version.gradle

def props = new Properties()
def propsFile = file("version.properties")
propsFile.withInputStream { stream ->
    props.load(stream)
    int versionCode = props['versionCode'].toInteger()
    project.ext.set('versionCode', versionCode)
    project.ext.set('versionName', getVersionName(props))
}

task incrementVersionCode {
    description "Incremement the version code by one"
    doLast {
        def versionCode = ++props['versionCode']
        props['versionCode'] = String.valueOf(versionCode)
        props.store(propsFile.newWriter(), null)
        project.ext.set('versionCode', versionCode)
        print "Increased version code to ${project.versionCode}"
    }
}

task incrementMajorVersion {
    description "Increment major version"
    doLast {
        props['major'] = String.valueOf(++props['major'])
        props['minor'] = '0'
        props['hotfix'] = '0'
        props.store(propsFile.newWriter(), null)
        project.ext.set('versionName', getVersionName(props))
        print "Increased major version to ${project.versionName}"
    }
}

task incrementMinorVersion {
    description "Increment minor version"
    doLast {
        props['minor'] = String.valueOf(++props['minor'])
        props['hotfix'] = '0'
        props.store(propsFile.newWriter(), null)
        project.ext.set('versionName', getVersionName(props))
        print "Increased minor version to ${project.versionName}"
    }
}

task incrementHotfixVersion {
    description "Increment hotfix version"
    doLast {
        props['hotfix'] = String.valueOf(++props['hotfix'])
        props.store(propsFile.newWriter(), null)
        project.ext.set('versionName', getVersionName(props))
        print "Increased hotfix version to ${project.versionName}"
    }
}

task commitVersionIncrease(type: Exec) {
    commandLine 'git', 'commit', '-am', "Increased to version ${project.versionName} v${project.versionCode}"
    doLast {
        props.store(propsFile.newWriter(), null)
        project.ext.set('versionCode', versionCode)
        project.ext.set('versionName', getVersionName(props))
        print "Increased to version ${project.versionName} v${project.versionCode}"
    }
}

def getVersionName(props) {
    int major = props['major'].toInteger()
    int minor = props['minor'].toInteger()
    int hotfix = props['hotfix'].toInteger()
    return "$major.$minor.$hotfix"
}