Added a placeholder for search in custom apps.

* Introduced a search placeholder for custom apps; if any custom app is configured not to show the title in the toolbar, it will display the search placeholder with a border. To implement this change, a layout has been added inside the toolbar.
* To enhance understanding of this change, proper comments have been added to the methods.

core/src/main/java/org/kiwix/kiwixmobile/core/di/modules/ActivityModule.kt

@@ -55,7 +55,8 @@ abstract class ActivityModule {
         urlIsValid: Boolean,
         menuClickListener: MenuClickListener,
         disableReadAloud: Boolean,
-        disableTabs: Boolean
+        disableTabs: Boolean,
+        disableSearch: Boolean
       ): MainMenu = MainMenu(
         activity,
         zimReaderContainer.zimFileReader,
@@ -64,6 +65,7 @@ abstract class ActivityModule {
         urlIsValid,
         disableReadAloud,
         disableTabs,
+        disableSearch,
         menuClickListener
       )
     }

core/src/main/java/org/kiwix/kiwixmobile/core/main/CoreReaderFragment.kt

@@ -48,6 +48,7 @@ import android.view.MenuInflater
 import android.view.MenuItem
 import android.view.MotionEvent
 import android.view.View
+import android.view.View.VISIBLE
 import android.view.ViewGroup
 import android.view.animation.AnimationUtils
 import android.webkit.WebBackForwardList
@@ -519,6 +520,9 @@ abstract class CoreReaderFragment :
       viewLifecycleOwner,
       Observer(::openSearchItem)
     )
+    toolbarWithSearchPlaceholder?.setOnClickListener {
+      openSearch(searchString = "", isOpenedFromTabView = false, false)
+    }
   }
 
   private fun initTabCallback() {
@@ -719,7 +723,7 @@ abstract class CoreReaderFragment :
     contentFrame?.visibility = View.GONE
     progressBar?.visibility = View.GONE
     backToTopButton?.hide()
-    tabSwitcherRoot?.visibility = View.VISIBLE
+    setTabSwitcherVisibility(VISIBLE)
     startAnimation(tabSwitcherRoot, R.anim.slide_down)
     tabsAdapter?.let { tabsAdapter ->
       tabRecyclerView?.let { recyclerView ->
@@ -737,6 +741,19 @@ abstract class CoreReaderFragment :
     mainMenu?.showTabSwitcherOptions()
   }
 
+  /**
+   * Sets the tabs switcher visibility, controlling the visibility of the tab.
+   * Subclasses, like CustomReaderFragment, override this method to provide custom
+   * behavior, such as hiding the placeholder in the toolbar when a custom app is configured
+   * not to show the title. This is necessary because the same toolbar is used for displaying tabs.
+   *
+   * WARNING: If modifying this method, ensure thorough testing with custom apps
+   * to verify proper functionality.
+   */
+  open fun setTabSwitcherVisibility(visibility: Int) {
+    tabSwitcherRoot?.visibility = visibility
+  }
+
   /**
    * Sets a top margin to the web views.
    *
@@ -775,7 +792,7 @@ abstract class CoreReaderFragment :
     )
     tabSwitcherRoot?.let {
       if (it.visibility == View.VISIBLE) {
-        it.visibility = View.GONE
+        setTabSwitcherVisibility(View.GONE)
         startAnimation(it, R.anim.slide_up)
         progressBar?.visibility = View.VISIBLE
         contentFrame?.visibility = View.VISIBLE

core/src/main/java/org/kiwix/kiwixmobile/core/main/MainMenu.kt

@@ -28,6 +28,7 @@ import org.kiwix.kiwixmobile.core.reader.ZimFileReader
 
 const val REQUEST_FILE_SEARCH = 1236
 
+@Suppress("LongParameterList")
 class MainMenu(
   private val activity: Activity,
   zimFileReader: ZimFileReader?,
@@ -36,6 +37,7 @@ class MainMenu(
   urlIsValid: Boolean,
   disableReadAloud: Boolean = false,
   disableTabs: Boolean = false,
+  private val disableSearch: Boolean = false,
   private val menuClickListener: MenuClickListener
 ) {
 
@@ -46,7 +48,8 @@ class MainMenu(
       urlIsValid: Boolean,
       menuClickListener: MenuClickListener,
       disableReadAloud: Boolean,
-      disableTabs: Boolean
+      disableTabs: Boolean,
+      disableSearch: Boolean = false
     ): MainMenu
   }
 
@@ -85,6 +88,10 @@ class MainMenu(
       tabSwitcherTextView = null
     }
 
+    if (disableSearch) {
+      search?.isVisible = false
+    }
+
     randomArticle.setShowAsAction(
       if (activity.resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE)
         MenuItem.SHOW_AS_ACTION_IF_ROOM
@@ -155,7 +162,13 @@ class MainMenu(
   }
 
   private fun setVisibility(visibility: Boolean, vararg menuItems: MenuItem?) {
-    menuItems.forEach { it?.isVisible = visibility }
+    menuItems.forEach {
+      if (it == search && disableSearch) {
+        it?.isVisible = false
+      } else {
+        it?.isVisible = visibility
+      }
+    }
   }
 
   fun tryExpandSearch(zimFileReader: ZimFileReader?) {

core/src/main/res/drawable/search_placeholder_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android">
+  <corners android:radius="3dip" />
+  <stroke
+    android:width="1.5dip"
+    android:color="@color/alabaster_white" />
+  <padding
+    android:bottom="0dip"
+    android:left="0dip"
+    android:right="0dip"
+    android:top="0dip" />
+</shape>

core/src/main/res/layout/layout_toolbar.xml

@@ -1,13 +1,34 @@
 <?xml version="1.0" encoding="utf-8"?>
-<merge>
+<merge xmlns:app="http://schemas.android.com/apk/res-auto">
 
   <androidx.appcompat.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/toolbar"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     app:popupTheme="@style/KiwixTheme"
     app:theme="@style/ThemeOverlay.MaterialComponents.Dark.ActionBar"
-    tools:showIn="@layout/fragment_search" />
+    tools:showIn="@layout/fragment_search">
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+      android:id="@+id/toolbarWithSearchPlaceholder"
+      android:layout_width="match_parent"
+      android:visibility="gone"
+      android:background="@drawable/search_placeholder_background"
+      android:layout_height="wrap_content">
+
+      <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="@string/search_label"
+        android:padding="5dip"
+        android:layout_marginStart="5dip"
+        app:layout_constraintTop_toTopOf="parent"
+        android:gravity="center_vertical"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:drawableRightCompat="@drawable/action_search"
+        android:drawablePadding="10dip" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+  </androidx.appcompat.widget.Toolbar>
 </merge>

core/src/main/res/menu/menu_main.xml

@@ -8,7 +8,8 @@
     android:title="@string/search_label"
     android:visible="false"
     app:showAsAction="always"
-    tools:visible="true" />
+    tools:visible="true"
+    tools:ignore="AlwaysShowAction" />
 
   <item
     android:id="@+id/menu_tab_switcher"
@@ -21,7 +22,7 @@
     android:icon="@drawable/ic_add_note"
     android:title="@string/note"
     android:visible="false"
-    app:showAsAction="ifRoom" />
+    app:showAsAction="never" />
 
 
   <item

custom/src/main/java/org/kiwix/kiwixmobile/custom/main/CustomReaderFragment.kt

@@ -88,6 +88,7 @@ class CustomReaderFragment : CoreReaderFragment() {
    * in a custom app, this function set the app logo on hamburger.
    */
   override fun setUpDrawerToggle(toolbar: Toolbar) {
+    super.setUpDrawerToggle(toolbar)
     if (BuildConfig.DISABLE_TITLE) {
       // if the title is disable then set the app logo to hamburger icon,
       // see https://github.com/kiwix/kiwix-android/issues/3528#issuecomment-1814905330
@@ -95,13 +96,29 @@ class CustomReaderFragment : CoreReaderFragment() {
         resources.getDimensionPixelSize(dimen.hamburger_icon_size)
       requireActivity().getResizedDrawable(R.mipmap.ic_launcher, iconSize, iconSize)
         ?.let { drawable ->
-          toolbar.navigationIcon = drawable
+          super.toolbar?.navigationIcon = drawable
         }
-    } else {
-      super.setUpDrawerToggle(toolbar)
     }
   }
 
+  /**
+   * Overrides the method to hide/show the placeholder from toolbar.
+   * When the "setting title" is disabled/enabled in a custom app,
+   * this function set the visibility of placeholder in toolbar when showing the tabs.
+   */
+  override fun setTabSwitcherVisibility(visibility: Int) {
+    if (BuildConfig.DISABLE_TITLE) {
+      // If custom apps are configured to show the placeholder,
+      // and if tabs are visible, hide the placeholder.
+      // If tabs are hidden, show the placeholder.
+      updateToolbarSearchPlaceholderVisibility(if (visibility == VISIBLE) GONE else VISIBLE)
+    } else {
+      // Permanently hide the placeholder if the custom app is not configured to show it.
+      updateToolbarSearchPlaceholderVisibility(GONE)
+    }
+    super.setTabSwitcherVisibility(visibility)
+  }
+
   private fun loadPageFromNavigationArguments() {
     val args = CustomReaderFragmentArgs.fromBundle(requireArguments())
     if (args.pageUrl.isNotEmpty()) {
@@ -277,13 +294,17 @@ class CustomReaderFragment : CoreReaderFragment() {
       // even if it is empty. If we do not set up this title,
       // the search screen will open if the user clicks on the toolbar from the tabs screen.
       actionBar?.title = " "
-      toolbarWithSearchPlaceholder?.visibility = VISIBLE
+      updateToolbarSearchPlaceholderVisibility(VISIBLE)
     } else {
-      toolbarWithSearchPlaceholder?.visibility = GONE
+      updateToolbarSearchPlaceholderVisibility(GONE)
       super.updateTitle()
     }
   }
 
+  private fun updateToolbarSearchPlaceholderVisibility(visibility: Int) {
+    toolbarWithSearchPlaceholder?.visibility = visibility
+  }
+
   override fun createNewTab() {
     newMainPageTab()
   }