Autoincrement VersionCode with gradle extra properties

Question

I\'m building an Android app with gradle. Until now I used the Manifest file to increase the versionCode, but I would like to read the versionCode from an external file and

Answer 1

The First Commented code will increment the number while each "Rebuild Project" and save the the value in the "Version Property" file.

The Second Commented code will generate new version name of APK file while "Build APKs".

android {
    compileSdkVersion 28
    buildToolsVersion "29.0.0"
    //==========================START==================================
    def Properties versionProps = new Properties()
    def versionPropsFile = file('version.properties')
    if(versionPropsFile.exists())
        versionProps.load(new FileInputStream(versionPropsFile))
    def code = (versionProps['VERSION_CODE'] ?: "0").toInteger() + 1
    versionProps['VERSION_CODE'] = code.toString()
    versionProps.store(versionPropsFile.newWriter(), null)
    //===========================END===================================
    defaultConfig {
        applicationId "com.example.myapp"
        minSdkVersion 15
        targetSdkVersion 28
        versionCode 1
        versionName "0.19"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            //=======================================START===============================================
            android.applicationVariants.all { variant ->
                variant.outputs.all {
                    def appName = "MyAppSampleName"
                    outputFileName = appName+"_v${variant.versionName}.${versionProps['VERSION_CODE']}.apk"
                }
            }
            //=======================================END===============================================
        }
    }
}