Refactored code to remove lint errors

* Now our minimum SDK version is 24 and we are using some conditions placed on behalf of this api level which are unused now, so we have removed those conditions.
* Removed `CompatV21` file as now it is unused.
* Renamed `CompatV23` to `CompatV24` and refactored the code to support our new minimum api level.
* Refactored `NetworkUtilsTest` to support api level 24.

app/src/main/java/org/kiwix/kiwixmobile/zimManager/fileselectView/effects/ShareFiles.kt

@@ -18,8 +18,6 @@
 
 package org.kiwix.kiwixmobile.zimManager.fileselectView.effects
 
-import android.net.Uri
-import android.os.Build
 import androidx.appcompat.app.AppCompatActivity
 import androidx.core.content.FileProvider
 import androidx.core.os.bundleOf
@@ -33,15 +31,11 @@ data class ShareFiles(private val selectedBooks: List<BookOnDisk>) :
   SideEffect<Unit> {
   override fun invokeWith(activity: AppCompatActivity) {
     val selectedFileContentURIs = selectedBooks.mapNotNull {
-      if (Build.VERSION.SDK_INT >= 24) {
-        FileProvider.getUriForFile(
-          activity,
-          activity.packageName + ".fileprovider",
-          it.file
-        )
-      } else {
-        Uri.fromFile(it.file)
-      }
+      FileProvider.getUriForFile(
+        activity,
+        activity.packageName + ".fileprovider",
+        it.file
+      )
     }
     activity.navigate(
       R.id.localFileTransferFragment,

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

@@ -90,9 +90,7 @@ abstract class CoreApp : Application() {
     if (BuildConfig.DEBUG) {
       StrictMode.setThreadPolicy(
         StrictMode.ThreadPolicy.Builder().apply {
-          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            detectResourceMismatches()
-          }
+          detectResourceMismatches()
           if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             detectUnbufferedIo()
           }
@@ -106,9 +104,7 @@ abstract class CoreApp : Application() {
       )
       StrictMode.setVmPolicy(
         VmPolicy.Builder().apply {
-          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            detectCleartextNetwork()
-          }
+          detectCleartextNetwork()
           if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             detectContentUriWithoutPermission()
           }

core/src/main/java/org/kiwix/kiwixmobile/core/compat/Compat.kt

@@ -32,7 +32,7 @@ import android.net.ConnectivityManager
  *
  *
  * Each implementation ends with a `V<n>` suffix, identifying the minimum API version on which this implementation
- * can be used. For example, see [CompatV21].
+ * can be used. For example, see [CompatV24].
  *
  *
  * Each implementation `CompatVn` should extend the implementation `CompatVm` for the greatest m<n such that `CompatVm`

core/src/main/java/org/kiwix/kiwixmobile/core/compat/CompatHelper.kt

@@ -29,8 +29,7 @@ class CompatHelper private constructor() {
   // Note: Needs ": Compat" or the type system assumes `Compat21`
   private val compatValue: Compat = when {
     sdkVersion >= Build.VERSION_CODES.TIRAMISU -> CompatV33()
-    sdkVersion >= Build.VERSION_CODES.M -> CompatV23()
-    else -> CompatV21()
+    else -> CompatV24()
   }
 
   companion object {

core/src/main/java/org/kiwix/kiwixmobile/core/compat/CompatV21.kt

@@ -1,60 +0,0 @@
-/*
- * Kiwix Android
- * Copyright (c) 2023 Kiwix <android.kiwix.org>
- * 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/>.
- *
- */
-@file:Suppress("DEPRECATION")
-
-package org.kiwix.kiwixmobile.core.compat
-
-import android.content.Intent
-import android.content.pm.PackageInfo
-import android.content.pm.PackageManager
-import android.content.pm.ResolveInfo
-import android.net.ConnectivityManager
-import android.net.ConnectivityManager.TYPE_WIFI
-import android.net.NetworkInfo.State.CONNECTED
-
-open class CompatV21 : Compat {
-  override fun queryIntentActivities(
-    packageManager: PackageManager,
-    intent: Intent,
-    flags: ResolveInfoFlagsCompat
-  ): List<ResolveInfo> = packageManager.queryIntentActivities(intent, flags.value.toInt())
-
-  override fun getPackageInformation(
-    packageName: String,
-    packageManager: PackageManager,
-    flag: Int
-  ): PackageInfo = packageManager.getPackageInfo(packageName, 0)
-
-  /**
-   * Checks if the device has a network connection with internet access.
-   *
-   * @param connectivity The ConnectivityManager instance.
-   * @return True if a network connection with internet access is available, false otherwise.
-   */
-  override fun isNetworkAvailable(connectivity: ConnectivityManager): Boolean =
-    connectivity.allNetworkInfo.any { it.state == CONNECTED }
-
-  /**
-   * Checks if the device is connected to a Wi-Fi network.
-   *
-   * @param connectivity The ConnectivityManager instance.
-   * @return True if connected to a Wi-Fi network, false otherwise.
-   */
-  override fun isWifi(connectivity: ConnectivityManager): Boolean =
-    connectivity.getNetworkInfo(TYPE_WIFI)?.isConnected == true
-}

core/src/main/java/org/kiwix/kiwixmobile/core/compat/CompatV24.kt

@@ -15,10 +15,10 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  *
  */
+@file:Suppress("DEPRECATION")
 
 package org.kiwix.kiwixmobile.core.compat
 
-import android.annotation.TargetApi
 import android.content.Intent
 import android.content.pm.PackageInfo
 import android.content.pm.PackageManager
@@ -27,24 +27,19 @@ import android.net.ConnectivityManager
 import android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET
 import android.net.NetworkCapabilities.TRANSPORT_WIFI
 
-const val API_23 = 23
-
-@TargetApi(API_23)
-open class CompatV23 : Compat {
-  private val compatV21 = CompatV21()
+open class CompatV24 : Compat {
 
   override fun queryIntentActivities(
     packageManager: PackageManager,
     intent: Intent,
     flags: ResolveInfoFlagsCompat
-  ): List<ResolveInfo> =
-    compatV21.queryIntentActivities(packageManager, intent, flags)
+  ): List<ResolveInfo> = packageManager.queryIntentActivities(intent, flags.value.toInt())
 
   override fun getPackageInformation(
     packageName: String,
     packageManager: PackageManager,
     flag: Int
-  ): PackageInfo = compatV21.getPackageInformation(packageName, packageManager, flag)
+  ): PackageInfo = packageManager.getPackageInfo(packageName, 0)
 
   /**
    * Checks if the device has a network connection with internet access.

core/src/main/java/org/kiwix/kiwixmobile/core/compat/CompatV33.kt

@@ -30,7 +30,7 @@ const val API_33 = 33
 
 @TargetApi(API_33)
 open class CompatV33 : Compat {
-  private val compatV23 = CompatV23()
+  private val compatV24 = CompatV24()
   override fun queryIntentActivities(
     packageManager: PackageManager,
     intent: Intent,
@@ -48,8 +48,8 @@ open class CompatV33 : Compat {
     packageManager.getPackageInfo(packageName, PackageInfoFlags.of(flag.toLong()))
 
   override fun isNetworkAvailable(connectivity: ConnectivityManager): Boolean =
-    compatV23.isNetworkAvailable(connectivity)
+    compatV24.isNetworkAvailable(connectivity)
 
   override fun isWifi(connectivity: ConnectivityManager): Boolean =
-    compatV23.isWifi(connectivity)
+    compatV24.isWifi(connectivity)
 }

core/src/main/java/org/kiwix/kiwixmobile/core/downloader/fetch/FetchDownloadNotificationManager.kt

@@ -146,11 +146,7 @@ class FetchDownloadNotificationManager(private val context: Context) :
       else -> ACTION_TYPE_INVALID
     }
     intent.putExtra(EXTRA_ACTION_TYPE, action)
-    val flags = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-      PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
-    } else {
-      PendingIntent.FLAG_UPDATE_CURRENT
-    }
+    val flags = PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT
     return PendingIntent.getBroadcast(
       context,
       downloadNotification.notificationId + action,
@@ -170,11 +166,8 @@ class FetchDownloadNotificationManager(private val context: Context) :
         addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
         putExtra(DOWNLOAD_NOTIFICATION_TITLE, downloadNotification.title)
       }
-      val pendingIntent = if (Build.VERSION.SDK_INT >= VERSION_CODES.M) {
+      val pendingIntent =
         getActivity(context, 0, internal, FLAG_IMMUTABLE or FLAG_UPDATE_CURRENT)
-      } else {
-        getActivity(context, 0, internal, FLAG_UPDATE_CURRENT)
-      }
       notificationBuilder.setContentIntent(pendingIntent)
       notificationBuilder.setAutoCancel(true)
     }

core/src/main/java/org/kiwix/kiwixmobile/core/extensions/ContextExtensions.kt

@@ -21,8 +21,6 @@ package org.kiwix.kiwixmobile.core.extensions
 import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
-import android.os.Build.VERSION
-import android.os.Build.VERSION_CODES
 import android.util.TypedValue
 import android.widget.Toast
 import androidx.annotation.AttrRes
@@ -53,11 +51,7 @@ fun Context.registerReceiver(baseBroadcastReceiver: BaseBroadcastReceiver): Inte
   registerReceiver(baseBroadcastReceiver, IntentFilter(baseBroadcastReceiver.action))
 
 val Context.locale: Locale
-  get() =
-    if (VERSION.SDK_INT >= VERSION_CODES.N) resources.configuration.locales.get(0)
-    else
-      @Suppress("DEPRECATION")
-      resources.configuration.locale
+  get() = resources.configuration.locales.get(0)
 
 fun Context.getAttribute(@AttrRes attributeRes: Int) = with(TypedValue()) {
   if (theme.resolveAttribute(attributeRes, this, true))

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

@@ -1315,16 +1315,12 @@ abstract class CoreReaderFragment :
     if (sharedPreferenceUtil?.isPlayStoreBuildWithAndroid11OrAbove() == false &&
       Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU
     ) {
-      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { // For Marshmallow & higher API levels
-        if (requireActivity().checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE)
-          == PackageManager.PERMISSION_GRANTED
-        ) {
-          isPermissionGranted = true
-        } else {
-          storagePermissionForNotesLauncher?.launch(Manifest.permission.WRITE_EXTERNAL_STORAGE)
-        }
-      } else { // For Android versions below Marshmallow 6.0 (API 23)
-        isPermissionGranted = true // As already requested at install time
+      if (requireActivity().checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE)
+        == PackageManager.PERMISSION_GRANTED
+      ) {
+        isPermissionGranted = true
+      } else {
+        storagePermissionForNotesLauncher?.launch(Manifest.permission.WRITE_EXTERNAL_STORAGE)
       }
     } else {
       isPermissionGranted = true
@@ -1665,10 +1661,7 @@ abstract class CoreReaderFragment :
   }
 
   private fun goToSearchWithText(intent: Intent) {
-    val searchString =
-      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
-        intent.getStringExtra(Intent.EXTRA_PROCESS_TEXT)
-      else ""
+    val searchString = intent.getStringExtra(Intent.EXTRA_PROCESS_TEXT)
     openSearch(
       searchString,
       isOpenedFromTabView = false,

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

@@ -23,7 +23,6 @@ import android.appwidget.AppWidgetManager
 import android.appwidget.AppWidgetProvider
 import android.content.Context
 import android.content.Intent
-import android.os.Build
 import android.widget.RemoteViews
 import org.kiwix.kiwixmobile.core.R
 import kotlin.reflect.KClass
@@ -50,21 +49,12 @@ abstract class CoreSearchWidget : AppWidgetProvider() {
 
   @SuppressLint("UnspecifiedImmutableFlag")
   private fun pendingIntent(context: Context, action: String) =
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-      PendingIntent.getActivity(
-        context,
-        (System.currentTimeMillis() % Int.MAX_VALUE).toInt(),
-        Intent(context, activityKClass.java).setAction(action),
-        0 or PendingIntent.FLAG_IMMUTABLE
-      )
-    } else {
-      PendingIntent.getActivity(
-        context,
-        (System.currentTimeMillis() % Int.MAX_VALUE).toInt(),
-        Intent(context, activityKClass.java).setAction(action),
-        0
-      )
-    }
+    PendingIntent.getActivity(
+      context,
+      (System.currentTimeMillis() % Int.MAX_VALUE).toInt(),
+      Intent(context, activityKClass.java).setAction(action),
+      0 or PendingIntent.FLAG_IMMUTABLE
+    )
 
   companion object {
     const val TEXT_CLICKED = "KiwixSearchWidget.TEXT_CLICKED"

core/src/main/java/org/kiwix/kiwixmobile/core/search/viewmodel/effects/SearchArgumentProcessing.kt

@@ -18,8 +18,6 @@
 
 package org.kiwix.kiwixmobile.core.search.viewmodel.effects
 
-import android.annotation.TargetApi
-import android.os.Build.VERSION_CODES
 import android.os.Bundle
 import androidx.appcompat.app.AppCompatActivity
 import kotlinx.coroutines.channels.Channel
@@ -38,7 +36,6 @@ data class SearchArgumentProcessing(
   private val bundle: Bundle?,
   private val actions: Channel<Action>
 ) : SideEffect<Unit> {
-  @TargetApi(VERSION_CODES.M)
   override fun invokeWith(activity: AppCompatActivity) {
     bundle?.let {
       actions.trySend(

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

@@ -18,8 +18,6 @@
 package org.kiwix.kiwixmobile.core.utils
 
 import android.content.Context
-import android.os.Build.VERSION
-import android.os.Build.VERSION_CODES
 import android.text.Html
 import android.text.Spanned
 import android.util.AttributeSet
@@ -43,14 +41,12 @@ object StyleUtils {
     return Xml.asAttributeSet(parser)
   }
 
-  @Suppress("DEPRECATION")
   @JvmStatic fun String?.fromHtml(): Spanned {
     return (this ?: "").let {
-      if (VERSION.SDK_INT >= VERSION_CODES.N) Html.fromHtml(
+      Html.fromHtml(
         this,
         Html.FROM_HTML_MODE_LEGACY
       )
-      else Html.fromHtml(this)
     }
   }
 }

core/src/test/java/org/kiwix/kiwixmobile/core/utils/NetworkUtilsTest.kt

@@ -20,12 +20,10 @@ package org.kiwix.kiwixmobile.core.utils
 
 import android.content.Context
 import android.net.ConnectivityManager
-import android.net.ConnectivityManager.TYPE_WIFI
 import android.net.Network
 import android.net.NetworkCapabilities
 import android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET
 import android.net.NetworkCapabilities.TRANSPORT_WIFI
-import android.net.NetworkInfo
 import io.mockk.every
 import io.mockk.mockk
 import org.junit.Assert.assertEquals
@@ -33,8 +31,7 @@ import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
 import org.junit.jupiter.api.Test
 import org.kiwix.kiwixmobile.core.R
-import org.kiwix.kiwixmobile.core.compat.CompatV21
-import org.kiwix.kiwixmobile.core.compat.CompatV23
+import org.kiwix.kiwixmobile.core.compat.CompatV24
 import java.util.regex.Pattern
 
 class NetworkUtilsTest {
@@ -43,26 +40,10 @@ class NetworkUtilsTest {
   private val connectivity: ConnectivityManager = mockk()
   private val networkCapabilities: NetworkCapabilities = mockk()
 
-  @Suppress("Deprecation")
   @Test
-  fun testNetworkAvailability_CompatV21() {
+  fun testNetworkAvailability_CompatV24() {
     every { context.getSystemService(Context.CONNECTIVITY_SERVICE) } returns connectivity
-    val compatV21 = CompatV21()
-    val networkInfo: NetworkInfo = mockk()
-
-    every { connectivity.allNetworkInfo } returns arrayOf(networkInfo)
-    every { networkInfo.state } returns NetworkInfo.State.CONNECTED
-
-    assertTrue(compatV21.isNetworkAvailable(connectivity))
-
-    every { networkInfo.state } returns NetworkInfo.State.DISCONNECTED
-    assertFalse(compatV21.isNetworkAvailable(connectivity))
-  }
-
-  @Test
-  fun testNetworkAvailability_CompatV23() {
-    every { context.getSystemService(Context.CONNECTIVITY_SERVICE) } returns connectivity
-    val compatV23 = CompatV23()
+    val compatV23 = CompatV24()
     val network: Network = mockk()
 
     every { connectivity.activeNetwork } returns network
@@ -74,25 +55,9 @@ class NetworkUtilsTest {
     assertFalse(compatV23.isNetworkAvailable(connectivity))
   }
 
-  @Suppress("Deprecation")
   @Test
-  fun test_isWifi_CompatV21() {
-    val compatV21 = CompatV21()
-    val networkInfo: NetworkInfo = mockk()
-
-    every { connectivity.getNetworkInfo(TYPE_WIFI) } returns networkInfo
-    every { networkInfo.type } returns ConnectivityManager.TYPE_WIFI
-    every { networkInfo.isConnected } returns true
-
-    assertTrue(compatV21.isWifi(connectivity))
-
-    every { networkInfo.isConnected } returns false
-    assertFalse(compatV21.isWifi(connectivity))
-  }
-
-  @Test
-  fun test_isWifi_CompatV23() {
-    val compatV23 = CompatV23()
+  fun test_isWifi_CompatV24() {
+    val compatV23 = CompatV24()
     val network: Network = mockk()
 
     every { connectivity.activeNetwork } returns network
@@ -104,21 +69,10 @@ class NetworkUtilsTest {
     assertFalse(compatV23.isWifi(connectivity))
   }
 
-  @Suppress("Deprecation")
   @Test
-  fun testNetworkAvailability_NoNetwork_CompatV21() {
+  fun testNetworkAvailability_NoNetwork_CompatV24() {
     every { context.getSystemService(Context.CONNECTIVITY_SERVICE) } returns connectivity
-    val compatV21 = CompatV21()
-
-    every { connectivity.allNetworkInfo } returns arrayOf()
-
-    assertFalse(compatV21.isNetworkAvailable(connectivity))
-  }
-
-  @Test
-  fun testNetworkAvailability_NoNetwork_CompatV23() {
-    every { context.getSystemService(Context.CONNECTIVITY_SERVICE) } returns connectivity
-    val compatV23 = CompatV23()
+    val compatV23 = CompatV24()
     val network: Network = mockk()
 
     every { connectivity.activeNetwork } returns network

lintConfig.xml

@@ -46,4 +46,5 @@
   </issue>
   <issue id="UnusedIds" severity="warning" />
   <issue id="DataExtractionRules" severity="warning" />
+  <issue id="ObsoleteSdkInt" severity="warning" />
 </lint>