fix: managed backstack for parent fragments in app settings

- added compact and non-compact tests for Preference navigation.

Author: iamit

AnkiDroid/src/androidTest/java/com/ichi2/anki/preferences/PreferencesNavigationTest.kt

@@ -0,0 +1,105 @@
+/**
+ *  Copyright (c) 2025 Amit Bisht <iamitsbisht07@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify it under
+ *  the terms of the GNU General Public License as published by the Free Software
+ *  Foundation; either version 3 of the License, or (at your option) any later
+ *  version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ *  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ *  PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.ichi2.anki.preferences
+
+import android.content.Context
+import androidx.recyclerview.widget.RecyclerView
+import androidx.test.core.app.ActivityScenario
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.espresso.Espresso.onView
+import androidx.test.espresso.Espresso.pressBack
+import androidx.test.espresso.action.ViewActions.click
+import androidx.test.espresso.action.ViewActions.typeText
+import androidx.test.espresso.assertion.ViewAssertions.doesNotExist
+import androidx.test.espresso.assertion.ViewAssertions.matches
+import androidx.test.espresso.contrib.DrawerActions
+import androidx.test.espresso.matcher.ViewMatchers.hasFocus
+import androidx.test.espresso.matcher.ViewMatchers.hasMinimumChildCount
+import androidx.test.espresso.matcher.ViewMatchers.isAssignableFrom
+import androidx.test.espresso.matcher.ViewMatchers.isDisplayed
+import androidx.test.espresso.matcher.ViewMatchers.withClassName
+import androidx.test.espresso.matcher.ViewMatchers.withId
+import androidx.test.espresso.matcher.ViewMatchers.withResourceName
+import androidx.test.espresso.matcher.ViewMatchers.withText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.ichi2.anki.IntentHandler
+import com.ichi2.anki.R
+import com.ichi2.anki.testutil.GrantStoragePermission
+import com.ichi2.anki.testutil.closeGetStartedScreenIfExists
+import com.ichi2.anki.testutil.grantPermissions
+import com.ichi2.anki.utils.isWindowCompact
+import org.hamcrest.Matchers.allOf
+import org.hamcrest.Matchers.endsWith
+import org.junit.Assume.assumeTrue
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class PreferencesNavigationTest {
+    @get:Rule
+    val runtimePermissionRule = grantPermissions(GrantStoragePermission.storagePermission)
+
+    /**
+     * Verifies navigation behavior when the search bar is tapped.
+     * - When the user searches for something using the search bar,the search view should close upon pressing the back button.
+     * - The back button should not close the entire preferences activity.
+     */
+    @Test
+    fun testOnCompactMode() {
+        val context = ApplicationProvider.getApplicationContext<Context>()
+        assumeTrue(context.resources.isWindowCompact())
+        ActivityScenario.launch(IntentHandler::class.java)
+        closeGetStartedScreenIfExists()
+        onView(withId(R.id.drawer_layout)).perform(DrawerActions.open())
+        onView(withId(R.id.nav_settings)).perform(click())
+        onView(withId(R.id.search)).perform(click())
+        onView(allOf(withId(R.id.search), hasFocus())).perform(typeText("Controls"))
+        pressBack()
+        // Checking the list of Settings Categories are displayed on the basis of our search "Controls"
+        onView(allOf(withResourceName("list"), isAssignableFrom(RecyclerView::class.java))).check(
+            matches(
+                hasMinimumChildCount(1),
+            ),
+        )
+        pressBack()
+        onView(withId(R.id.settings_container)).check(matches(isDisplayed()))
+    }
+
+    /**
+     * Verifies navigation behavior when multiple menus are opened.
+     * - Even after opening multiple menus, pressing the back button should
+     * close the preference activity instead of navigating back through the previously opened menus.
+     */
+    @Test
+    fun testOnNonCompactMode() {
+        fun isTablet(context: Context): Boolean = context.resources.configuration.smallestScreenWidthDp >= 600
+
+        val context = ApplicationProvider.getApplicationContext<Context>()
+        assumeTrue(isTablet(context))
+        ActivityScenario.launch(IntentHandler::class.java)
+        closeGetStartedScreenIfExists()
+        onView(withId(R.id.drawer_layout)).perform(DrawerActions.open())
+        onView(withId(R.id.nav_settings)).perform(click())
+        onView(withId(R.id.search)).perform(click())
+        onView(allOf(withId(R.id.search), hasFocus())).perform(typeText("Card"))
+        onView(withText(R.string.card_zoom)).perform(click())
+        onView(withId(R.id.settings_container)).check(matches(isDisplayed()))
+        onView(withText(R.string.notification_pref)).perform(click())
+        pressBack()
+        onView(withClassName(endsWith("PreferencesActivity"))).check(doesNotExist())
+    }
+}

AnkiDroid/src/main/java/com/ichi2/anki/preferences/Preferences.kt

@@ -54,6 +54,8 @@ class PreferencesFragment :
             override fun handleOnBackPressed() {
                 if (!settingsIsSplit && childFragmentManager.backStackEntryCount > 0) {
                     childFragmentManager.popBackStack()
+                } else if (parentFragmentManager.backStackEntryCount > 0) {
+                    parentFragmentManager.popBackStack()
                 } else {
                     requireActivity().finish()
                 }