Fixed: Download zim files in Android/media/org.kiwix/kiwixmobile/ folder instead of internal app-specific directory.

* Now all the downloading files will store in this public app-specific directory.
* Refactored the code to show this new location in storageSelection dialog for both internal and external storage.
* Updated the `README.md` file to educate user that how they can read already downloaded zim files in PS version.
* Refactored the test cases according to this change.

README.md

@@ -28,7 +28,11 @@ Play Store policies.  The Play Store variant of Kiwix does not require
 the `MANAGE_EXTERNAL_STORAGE` permission anymore, which is necessary
 to scan storage and access ZIM files at arbitrary locations.
 Therefore, the storage scanning & file picking functionalities are not
-available in this variant anymore.  To use the full version of Kiwix
+available in this variant anymore. For already downloaded ZIM files, You can copy
+them to the `Android/media/org.kiwix.kiwixmobile/` folder, and the application will read them.
+Before uninstalling the application, please ensure that you move all your ZIM files
+from this folder, as they will be automatically deleted when the application is uninstalled
+or if the application data is cleared.  To use the full version of Kiwix
 and benefit of the ZIM file picker feature, you can download it
 directly from the [official
 repository](https://download.kiwix.org/release/kiwix-android/) or use

core/src/main/java/eu/mhutti1/utils/storage/StorageDeviceUtils.kt

@@ -19,6 +19,7 @@
 package eu.mhutti1.utils.storage
 
 import android.content.Context
+import android.content.ContextWrapper
 import android.os.Environment
 import androidx.core.content.ContextCompat
 import java.io.File
@@ -28,7 +29,8 @@ import java.util.ArrayList
 
 object StorageDeviceUtils {
   @JvmStatic
-  fun getWritableStorage(context: Context) = validate(externalFilesDirsDevices(context, true), true)
+  fun getWritableStorage(context: Context) =
+    validate(externalMediaFilesDirsDevices(context), true)
 
   @JvmStatic
   fun getReadableStorage(context: Context): List<StorageDevice> {
@@ -36,6 +38,7 @@ object StorageDeviceUtils {
       add(environmentDevices(context))
       addAll(externalMountPointDevices())
       addAll(externalFilesDirsDevices(context, false))
+      addAll(externalMediaFilesDirsDevices(context))
       // Scan the app-specific directory as well because we have limitations in scanning
       // all directories on Android 11 and above in the Play Store variant.
       // If a user copies the ZIM file to the app-specific directory on the SD card,
@@ -55,6 +58,12 @@ object StorageDeviceUtils {
     .filterNotNull()
     .mapIndexed { index, dir -> StorageDevice(generalisePath(dir.path, writable), index == 0) }
 
+  private fun externalMediaFilesDirsDevices(
+    context: Context
+  ) = ContextWrapper(context).externalMediaDirs
+    .filterNotNull()
+    .mapIndexed { index, dir -> StorageDevice(generalisePath(dir.path, true), index == 0) }
+
   private fun externalMountPointDevices(): Collection<StorageDevice> =
     ExternalPaths.possiblePaths.fold(mutableListOf(), { acc, path ->
       acc.apply {

core/src/main/java/org/kiwix/kiwixmobile/core/utils/SharedPreferenceUtil.kt

@@ -18,6 +18,7 @@
 package org.kiwix.kiwixmobile.core.utils
 
 import android.content.Context
+import android.content.ContextWrapper
 import android.content.SharedPreferences
 import android.os.Build
 import androidx.appcompat.app.AppCompatDelegate
@@ -106,12 +107,12 @@ class SharedPreferenceUtil @Inject constructor(val context: Context) {
     get() {
       val storage = sharedPreferences.getString(PREF_STORAGE, null)
       return when {
-        storage == null -> getPublicDirectoryPath(defaultStorage()).also {
+        storage == null -> getPublicDirectoryPath(defaultPublicStorage()).also {
           putPrefStorage(it)
           putStoragePosition(0)
         }
 
-        !File(storage).isFileExist() -> getPublicDirectoryPath(defaultStorage()).also {
+        !File(storage).isFileExist() -> getPublicDirectoryPath(defaultPublicStorage()).also {
           putStoragePosition(0)
         }
 
@@ -126,6 +127,10 @@ class SharedPreferenceUtil @Inject constructor(val context: Context) {
     getExternalFilesDirs(context, null)[0]?.path
       ?: context.filesDir.path // a workaround for emulators
 
+  fun defaultPublicStorage(): String =
+    ContextWrapper(context).externalMediaDirs[0]?.path
+      ?: context.filesDir.path // a workaround for emulators
+
   fun getPrefStorageTitle(defaultTitle: String): String =
     sharedPreferences.getString(PREF_STORAGE_TITLE, defaultTitle) ?: defaultTitle
 

custom/src/main/java/org/kiwix/kiwixmobile/custom/download/effects/SetPreferredStorageWithMostSpace.kt

@@ -19,7 +19,6 @@
 package org.kiwix.kiwixmobile.custom.download.effects
 
 import androidx.appcompat.app.AppCompatActivity
-import androidx.core.content.ContextCompat
 import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.core.settings.StorageCalculator
 import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
@@ -30,7 +29,7 @@ class SetPreferredStorageWithMostSpace @Inject constructor(
   private val sharedPreferenceUtil: SharedPreferenceUtil
 ) : SideEffect<Unit> {
   override fun invokeWith(activity: AppCompatActivity) {
-    ContextCompat.getExternalFilesDirs(activity, null)
+    activity.externalMediaDirs
       .filterNotNull()
       .maxBy(storageCalculator::availableBytes)
       ?.let { sharedPreferenceUtil.putPrefStorage(it.path) }

custom/src/test/java/org/kiwix/kiwixmobile/custom/download/effects/SetPreferredStorageWithMostSpaceTest.kt

@@ -19,10 +19,8 @@
 package org.kiwix.kiwixmobile.custom.download.effects
 
 import androidx.appcompat.app.AppCompatActivity
-import androidx.core.content.ContextCompat
 import io.mockk.every
 import io.mockk.mockk
-import io.mockk.mockkStatic
 import io.mockk.verify
 import org.junit.jupiter.api.Test
 import org.kiwix.kiwixmobile.core.settings.StorageCalculator
@@ -36,10 +34,9 @@ internal class SetPreferredStorageWithMostSpaceTest {
     val storageCalculator = mockk<StorageCalculator>()
     val sharedPreferenceUtil = mockk<SharedPreferenceUtil>()
     val activity = mockk<AppCompatActivity>()
-    mockkStatic(ContextCompat::class)
     val directoryWithMoreStorage = mockk<File>()
     val directoryWithLessStorage = mockk<File>()
-    every { ContextCompat.getExternalFilesDirs(activity, null) } returns arrayOf(
+    every { activity.externalMediaDirs } returns arrayOf(
       directoryWithMoreStorage, null, directoryWithLessStorage
     )
     every { storageCalculator.availableBytes(directoryWithMoreStorage) } returns 1