Automatically adding build time to your Android app

build.gradle

android {
    compileSdkVersion 28
    defaultConfig {
        minSdkVersion 17
        targetSdkVersion 28
        versionCode 8
        versionName "1.1.0"
        buildConfigField "java.util.Date", "BUILD_TIME", "new java.util.Date(" + System.currentTimeMillis() + "L)"
    }
}

SettingsFragment.kt

    private fun setupVersionInfo() {
        findPreference(getString(R.string.pref_version)).title = "V${BuildConfig.VERSION_NAME}"
        findPreference(getString(R.string.pref_version)).summary = String.format(
            getString(R.string.version_summary),
            BuildConfig.VERSION_CODE,
            SimpleDateFormat("dd MMM yyy", Locale.US).format(BuildConfig.BUILD_TIME)
        )
    }