From 456e348078e9d4447c712b3592b2abb308a535b0 Mon Sep 17 00:00:00 2001
From: MohitMaliFtechiz <futuretechnoworld.mohit@gmail.com>
Date: Thu, 14 Aug 2025 18:31:04 +0530
Subject: [PATCH] Fixed: When changing the app's language, a blank screen
 appeared instead of the settings screen.

* The issue occurred because we reopened the settings screen immediately after removing it from the back stack, causing Compose to not settle the previous frame and display a blank screen.
* Resolved by allowing the popBackStack frame to settle before reopening the settings screen.
* Removed some unused code from the project.
---
 .../core/settings/CoreSettingsFragment.kt     | 26 +++++++++++++++----
 .../core/ui/components/KiwixAppBar.kt         | 26 -------------------
 2 files changed, 21 insertions(+), 31 deletions(-)

diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/settings/CoreSettingsFragment.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/settings/CoreSettingsFragment.kt
index 2e41ad9d1..9dce63794 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/settings/CoreSettingsFragment.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/settings/CoreSettingsFragment.kt
@@ -35,6 +35,7 @@ import android.widget.Toast
 import androidx.activity.result.ActivityResultLauncher
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.withFrameNanos
 import androidx.compose.ui.platform.ComposeView
 import androidx.compose.ui.viewinterop.AndroidView
 import androidx.core.content.ContextCompat
@@ -183,12 +184,27 @@ abstract class CoreSettingsFragment : SettingsContract.View, BaseFragment() {
     composeView = it
   }
 
+  /**
+   * Restarts the Settings screen by popping it from the back stack and reopening it.
+   *
+   * This is useful when we need to refresh the Settings UI (e.g., after a app's language
+   * change) without fully recreating the activity.
+   *
+   * Steps:
+   * 1. Get the CoreMainActivity reference to access the NavController.
+   * 2. Pop the Settings fragment from the navigation back stack.
+   * 3. Wait for one frame so the back stack can settle after the pop operation.
+   * 4. Navigate back to the Settings fragment route.
+   */
   private fun restartActivity() {
-    (activity as CoreMainActivity?)?.let {
-      it.navController.apply {
-        popBackStack()
-        navigate(it.settingsFragmentRoute)
-      }
+    val coreMainActivity = activity as? CoreMainActivity ?: return
+    val navController = coreMainActivity.navController
+    navController.popBackStack()
+    coreMainActivity.uiCoroutineScope.launch {
+      // Wait for one frame to ensure the back stack has settled before navigation
+      // Bug fix #4387
+      withFrameNanos { }
+      navController.navigate(coreMainActivity.settingsFragmentRoute)
     }
   }
 
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/ui/components/KiwixAppBar.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/ui/components/KiwixAppBar.kt
index d06f657a7..193b220c3 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/ui/components/KiwixAppBar.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/ui/components/KiwixAppBar.kt
@@ -29,7 +29,6 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.only
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.statusBars
-import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.MoreVert
 import androidx.compose.material3.DropdownMenu
@@ -44,21 +43,16 @@ import androidx.compose.material3.TopAppBar
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.material3.TopAppBarScrollBehavior
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
-import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.runtime.setValue
-import androidx.compose.runtime.snapshotFlow
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.style.TextOverflow
-import org.kiwix.kiwixmobile.core.downloader.downloadManager.ZERO
 import org.kiwix.kiwixmobile.core.ui.models.ActionMenuItem
 import org.kiwix.kiwixmobile.core.ui.models.toPainter
 import org.kiwix.kiwixmobile.core.ui.theme.Black
@@ -234,23 +228,3 @@ private fun OverflowMenuItems(
     }
   }
 }
-
-@Composable
-fun rememberBottomNavigationVisibility(lazyListState: LazyListState?): Boolean {
-  var isToolbarVisible by remember { mutableStateOf(true) }
-  var lastScrollIndex by remember { mutableIntStateOf(ZERO) }
-  val updatedLazyListState = rememberUpdatedState(lazyListState)
-
-  LaunchedEffect(updatedLazyListState) {
-    updatedLazyListState.value?.let { state ->
-      snapshotFlow { state.firstVisibleItemIndex }
-        .collect { newScrollIndex ->
-          if (newScrollIndex != lastScrollIndex) {
-            isToolbarVisible = newScrollIndex < lastScrollIndex
-            lastScrollIndex = newScrollIndex
-          }
-        }
-    }
-  }
-  return isToolbarVisible
-}