Pressing back button closes the drawer instead of exiting the app

app/src/androidTest/java/fr/chenry/android/freshrss/activities/MainActivityTest.kt

 package fr.chenry.android.freshrss.activities
 
+import android.app.Activity
+import androidx.core.view.GravityCompat
+import androidx.drawerlayout.widget.DrawerLayout
 import androidx.test.espresso.Espresso.onView
+import androidx.test.espresso.NoActivityResumedException
+import androidx.test.espresso.action.ViewActions
 import androidx.test.espresso.action.ViewActions.click
 import androidx.test.espresso.assertion.ViewAssertions.matches
 import androidx.test.espresso.contrib.DrawerActions
@@ -9,10 +14,15 @@ import androidx.test.espresso.contrib.DrawerMatchers.isOpen
 import androidx.test.espresso.matcher.ViewMatchers.*
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.filters.LargeTest
+import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.rule.ActivityTestRule
+import androidx.test.runner.lifecycle.ActivityLifecycleMonitorRegistry
+import androidx.test.runner.lifecycle.Stage
 import fr.chenry.android.freshrss.R
+import junit.framework.TestCase.assertFalse
 import org.junit.Rule
 import org.junit.Test
+import org.junit.rules.ExpectedException
 import org.junit.runner.RunWith
 
 @RunWith(AndroidJUnit4::class)
@@ -23,14 +33,41 @@ class MainActivityTest {
     @get:Rule
     val activityRule = ActivityTestRule(MainActivity::class.java)
 
+    @get:Rule
+    var exceptionRule = ExpectedException.none()
+
     @Test
-    fun `check-drawer-is-closed-when-adding-a-new-subscription`() {
+    fun `drawer-is-closed-when-adding-a-new-subscription`() {
         // Open drawer
         onView(withId(R.id.activity_main_navigation_drawer)).perform(DrawerActions.open())
         onView(withId(R.id.activity_main_navigation_drawer)).check(matches(isOpen()))
         onView(withText(R.string.title_add_subscription)).perform(click())
-        onView(withText(android.R.string.ok)).perform(click())
+
+        val drawer = getActivityInstance().findViewById<DrawerLayout>((R.id.activity_main_navigation_drawer))
+        assertFalse(drawer.isDrawerOpen(GravityCompat.START))
+    }
+
+    @Test
+    fun `drawer-is-closed-before-application-exits`() {
+        onView(withId(R.id.activity_main_navigation_drawer)).perform(DrawerActions.open())
+        onView(withId(R.id.activity_main_navigation_drawer)).check(matches(isOpen()))
+        onView(isRoot()).perform(ViewActions.pressBack())
         onView(withId(R.id.activity_main_navigation_drawer)).check(matches(isClosed()))
+
+        // We assert that pressing back again exists the app
+        exceptionRule.expect(NoActivityResumedException::class.java)
+        onView(isRoot()).perform(ViewActions.pressBack())
+
     }
 
+    // See https://stackoverflow.com/a/60341723/3459089
+    private fun getActivityInstance(): Activity {
+        val currentActivity = arrayOf<Activity?>(null)
+        InstrumentationRegistry.getInstrumentation().runOnMainSync {
+            val resumedActivity = ActivityLifecycleMonitorRegistry.getInstance().getActivitiesInStage(Stage.RESUMED)
+            val it: Iterator<Activity> = resumedActivity.iterator()
+            currentActivity[0] = it.next()
+        }
+        return currentActivity[0]!!
+    }
 }

app/src/main/java/fr/chenry/android/freshrss/activities/MainActivity.kt

@@ -17,8 +17,7 @@ import fr.chenry.android.freshrss.components.navigationdrawer.AddSubscriptionDia
 import fr.chenry.android.freshrss.components.subscriptions.MainSubscriptionFragmentDirections
 import fr.chenry.android.freshrss.store.Store
 import fr.chenry.android.freshrss.store.viewmodels.AccountVM
-import fr.chenry.android.freshrss.utils.BurgerMenuDrawerListener
-import fr.chenry.android.freshrss.utils.e
+import fr.chenry.android.freshrss.utils.*
 import kotlinx.android.synthetic.main.activity_main.*
 
 class MainActivity: AppCompatActivity() {
@@ -59,8 +58,7 @@ class MainActivity: AppCompatActivity() {
 
     override fun onOptionsItemSelected(item: MenuItem?): Boolean {
         if(item?.itemId == android.R.id.home && backstackCount == 0) {
-            val isOpened = drawerLayout.isDrawerOpen(activity_main_navigation_view)
-            if(isOpened) drawerLayout.closeDrawers()
+            if(isDrawerOpen()) drawerLayout.closeDrawers()
             else drawerLayout.openDrawer(activity_main_navigation_view)
 
             return true
@@ -82,6 +80,12 @@ class MainActivity: AppCompatActivity() {
     fun onSettingsItemClick(@Suppress("UNUSED_PARAMETER") item: MenuItem) =
         navigation.navigate(MainSubscriptionFragmentDirections.mainSubscriptionsToSettings())
 
+    override fun onBackPressed() =
+        if(navigation.isTopLevelDestination() && isDrawerOpen()) drawerLayout.closeDrawers()
+        else super.onBackPressed()
+
     override fun onSupportNavigateUp(): Boolean =
         navigation.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
+
+    private fun isDrawerOpen() = drawerLayout.isDrawerOpen(activity_main_navigation_view)
 }

app/src/main/java/fr/chenry/android/freshrss/utils/BurgerMenuDrawerListener.kt

@@ -18,27 +18,26 @@ class BurgerMenuDrawerListener(
     private val navigation: NavController
 ): DrawerLayout.DrawerListener {
 
+
     private val drawable = HamburgerCrossDrawable(supportActionBar.themedContext)
-    private val isTopLevelDest: Boolean
-        inline get() = navigation.currentDestination?.id == navigation.graph.startDestination
 
     override fun onDrawerStateChanged(newState: Int) {
-        if(isTopLevelDest) supportActionBar.setHomeAsUpIndicator(drawable)
+        if(navigation.isTopLevelDestination()) supportActionBar.setHomeAsUpIndicator(drawable)
     }
 
     override fun onDrawerSlide(drawerView: View, slideOffset: Float) {
-        if(isTopLevelDest) setPosition(slideOffset)
+        if(navigation.isTopLevelDestination()) setPosition(slideOffset)
     }
 
     override fun onDrawerClosed(drawerView: View) {
-        if(isTopLevelDest) {
+        if(navigation.isTopLevelDestination()) {
             supportActionBar.setHomeActionContentDescription(R.string.navigation_drawer_open)
             setPosition(0f)
         }
     }
 
     override fun onDrawerOpened(drawerView: View) {
-        if(isTopLevelDest) {
+        if(navigation.isTopLevelDestination()) {
             supportActionBar.setHomeActionContentDescription(R.string.navigation_drawer_close)
             setPosition(1f)
         }

app/src/main/java/fr/chenry/android/freshrss/utils/KotlinExtensions.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import android.net.ConnectivityManager
 import android.net.Uri
 import android.util.Log
+import androidx.navigation.NavController
 import com.fasterxml.jackson.databind.DeserializationFeature
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.datatype.joda.JodaModule
@@ -16,10 +17,7 @@ import nl.komponents.kovenant.Kovenant.deferred
 import nl.komponents.kovenant.Promise
 import nl.komponents.kovenant.task
 import org.apache.commons.text.StringEscapeUtils
-import org.joda.time.DateTimeZone
-import org.joda.time.LocalDateTime
 import java.net.URL
-import java.util.TimeZone
 import kotlin.reflect.full.companionObjectInstance
 
 val JACKSON_OBJECT_MAPPER: ObjectMapper = ObjectMapper().registerKotlinModule()
@@ -124,7 +122,5 @@ fun <T> List<T>.firstOrElse(other: T): T {
     return if (isEmpty()) other else this[0]
 }
 
-fun LocalDateTime.toUserDateTime() =
-    this.toDateTime(DateTimeZone.UTC)
-        .withZone(DateTimeZone.forTimeZone(TimeZone.getDefault()))
-        .toLocalDateTime()
+fun NavController.isTopLevelDestination(): Boolean =
+    this.currentDestination?.id == this.graph.startDestination