Providing Up navigation from Notification

ProvidingUpNavigation.kt

// https://developer.android.com/training/implementing-navigation/ancestral

    override fun onSupportNavigateUp(): Boolean {
        navigationUp(false)
        return true
    }

    override fun onBackPressed() {
        navigationUp(true)
    }

    private fun navigationUp(onBackPressed: Boolean) {
        val upIntent: Intent? = NavUtils.getParentActivityIntent(this)
        when {
            upIntent == null -> throw IllegalStateException("No Parent Activity Intent")
            NavUtils.shouldUpRecreateTask(this, upIntent) || intent.action == ACTION_NOTIFICATION -> {
                TaskStackBuilder.create(this)
                        .addNextIntentWithParentStack(upIntent)
                        .startActivities()
            }
            else -> {
                if (onBackPressed) {
                    super.onBackPressed()
                } else {
                    NavUtils.navigateUpFromSameTask(this)
                }
            }
        }
    }

zManifest.xml

<application ... >
    ...
    <!-- The main/home activity (it has no parent activity) -->
    <activity
        android:name="com.example.myfirstapp.MainActivity" ...>
        ...
    </activity>
    <!-- A child of the main activity -->
    <activity
        android:name="com.example.myfirstapp.DisplayMessageActivity"
        android:label="@string/title_activity_display_message"
        android:parentActivityName="com.example.myfirstapp.MainActivity" >
        <!-- Parent activity meta-data to support 4.0 and lower -->
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.example.myfirstapp.MainActivity" />
    </activity>
</application>