Get versionName and versionCode from APK file.

getAaptPath.groovy

def getAaptPath = { ->
    def sdkDir = android.sdkDirectory
    def buildToolsDir = new File(sdkDir, "build-tools")
    def versions = buildToolsDir.list()
    def latestBuildToolsDir = new File(buildToolsDir, versions[-1])
    return "${new File(latestBuildToolsDir, "aapt").absoluteFile}"
}

getVersionInfo.groovy

def getVersionInfo = { File apkFile ->
    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine getAaptPath(), "dump", "badging", apkFile.absoluteFile
        standardOutput = stdout
    }
    return new VersionInfo(apkFile, stdout.toString())
}

versioninfo.gradle

import java.util.regex.Pattern

class VersionInfo {
    private static Pattern VERSION_NAME_PATTERN = Pattern.compile("versionName='([0-9]+(\\.[0-9]+)+)'", Pattern.MULTILINE)
    private static Pattern VERSION_CODE_PATTERN = Pattern.compile("versionCode='([0-9]+)'", Pattern.MULTILINE)
    public File apkFile;
    public String versionName;
    public int versionCode;

    public VersionInfo(File apkFile, String aaptOutput) {
        def nameMatcher = VERSION_NAME_PATTERN.matcher(aaptOutput)
        def codeMatcher = VERSION_CODE_PATTERN.matcher(aaptOutput)

        nameMatcher.find()
        codeMatcher.find()

        this.apkFile = apkFile;
        this.versionName = nameMatcher.group(1)
        this.versionCode = Integer.parseInt(codeMatcher.group(1), 10)
    }

    @Override
    String toString() {
        return "VersionInfo(\"${apkFile}\", versionName=\"${versionName}\", versionCode=\"${versionCode}\")"
    }
}

def getAaptPath = { ->
    def sdkDir = android.sdkDirectory
    def buildToolsDir = new File(sdkDir, "build-tools")
    def versions = buildToolsDir.list()
    def latestBuildToolsDir = new File(buildToolsDir, versions[-1])
    return "${new File(latestBuildToolsDir, "aapt").absoluteFile}"
}

def getVersionInfo = { File apkFile ->
    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine getAaptPath(), "dump", "badging", apkFile.absoluteFile
        standardOutput = stdout
    }
    return new VersionInfo(apkFile, stdout.toString())
}

VersionInfo.groovy

class VersionInfo {
    public static Pattern VERSION_NAME_PATTERN = Pattern.compile("versionName='([0-9]+(\\.[0-9]+)+)'", Pattern.MULTILINE)
    public static Pattern VERSION_CODE_PATTERN = Pattern.compile("versionCode='([0-9]+)'", Pattern.MULTILINE)
    public File apkFile;
    public String versionName;
    public int versionCode;

    public VersionInfo(File apkFile, String versionName, int versionCode) {
        this.apkFile = apkFile;
        this.versionName = versionName
        this.versionCode = versionCode
    }

    @Override
    String toString() {
        return "VersionInfo(\"${apkFile}\", versionName=\"${versionName}\", versionCode=\"${versionCode}\")"
    }
}