64 Custom apps should validate their expansion files and re-download if corrupt/missing - add Custom Download flow

app/src/main/java/org/kiwix/kiwixmobile/KiwixViewModelFactory.java

@@ -19,40 +19,17 @@
 package org.kiwix.kiwixmobile;
 
 import androidx.lifecycle.ViewModel;
-import androidx.lifecycle.ViewModelProvider;
 import java.util.Map;
 import javax.inject.Inject;
 import javax.inject.Provider;
+import org.kiwix.kiwixmobile.core.ViewModelFactory;
 import org.kiwix.kiwixmobile.di.KiwixScope;
 
 @KiwixScope
-public class KiwixViewModelFactory implements ViewModelProvider.Factory {
-  private final Map<Class<? extends ViewModel>, Provider<ViewModel>> creators;
+public class KiwixViewModelFactory extends ViewModelFactory {
 
   @Inject
   public KiwixViewModelFactory(Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
-    this.creators = creators;
-  }
-
-  @SuppressWarnings("unchecked")
-  @Override
-  public <T extends ViewModel> T create(Class<T> modelClass) {
-    Provider<? extends ViewModel> creator = creators.get(modelClass);
-    if (creator == null) {
-      for (Map.Entry<Class<? extends ViewModel>, Provider<ViewModel>> entry : creators.entrySet()) {
-        if (modelClass.isAssignableFrom(entry.getKey())) {
-          creator = entry.getValue();
-          break;
-        }
-      }
-    }
-    if (creator == null) {
-      throw new IllegalArgumentException("unknown model class " + modelClass);
-    }
-    try {
-      return (T) creator.get();
-    } catch (Exception e) {
-      throw new RuntimeException(e);
-    }
+    super(creators);
   }
 }

app/src/main/java/org/kiwix/kiwixmobile/language/viewmodel/LanguageViewModel.kt

@@ -22,6 +22,7 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import io.reactivex.disposables.CompositeDisposable
 import io.reactivex.processors.PublishProcessor
+import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.core.dao.NewLanguagesDao
 import org.kiwix.kiwixmobile.language.adapter.LanguageListItem.LanguageItem
 import org.kiwix.kiwixmobile.language.viewmodel.Action.Filter
@@ -31,7 +32,6 @@ import org.kiwix.kiwixmobile.language.viewmodel.Action.UpdateLanguages
 import org.kiwix.kiwixmobile.language.viewmodel.State.Content
 import org.kiwix.kiwixmobile.language.viewmodel.State.Loading
 import org.kiwix.kiwixmobile.language.viewmodel.State.Saving
-import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.SideEffect
 import javax.inject.Inject
 
 class LanguageViewModel @Inject constructor(

app/src/main/java/org/kiwix/kiwixmobile/language/viewmodel/SaveLanguagesAndFinish.kt

@@ -22,7 +22,7 @@ import io.reactivex.Flowable
 import io.reactivex.schedulers.Schedulers
 import org.kiwix.kiwixmobile.core.dao.NewLanguagesDao
 import org.kiwix.kiwixmobile.core.zim_manager.Language
-import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.SideEffect
+import org.kiwix.kiwixmobile.core.base.SideEffect
 
 data class SaveLanguagesAndFinish(
   val languages: List<Language>,

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/ZimManageViewModel.kt

@@ -66,7 +66,7 @@ import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.DeleteFiles
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.None
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.OpenFile
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.ShareFiles
-import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.SideEffect
+import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects.StartMultiSelection
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem
 import org.kiwix.kiwixmobile.zim_manager.library_view.adapter.LibraryListItem.BookItem

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/download_view/DownloadViewHolder.kt

@@ -17,7 +17,6 @@
  */
 package org.kiwix.kiwixmobile.zim_manager.download_view
 
-import android.content.Context
 import android.view.View
 import androidx.recyclerview.widget.RecyclerView
 import kotlinx.android.extensions.LayoutContainer
@@ -29,12 +28,6 @@ import kotlinx.android.synthetic.main.download_item.favicon
 import kotlinx.android.synthetic.main.download_item.stop
 import kotlinx.android.synthetic.main.download_item.title
 import org.kiwix.kiwixmobile.core.downloader.model.DownloadItem
-import org.kiwix.kiwixmobile.core.downloader.model.DownloadState
-import org.kiwix.kiwixmobile.core.downloader.model.DownloadState.Failed
-import org.kiwix.kiwixmobile.core.downloader.model.DownloadState.Paused
-import org.kiwix.kiwixmobile.core.downloader.model.DownloadState.Pending
-import org.kiwix.kiwixmobile.core.downloader.model.DownloadState.Running
-import org.kiwix.kiwixmobile.core.downloader.model.DownloadState.Successful
 import org.kiwix.kiwixmobile.core.extensions.setBitmap
 
 class DownloadViewHolder(override val containerView: View) : RecyclerView.ViewHolder(containerView),
@@ -50,21 +43,7 @@ class DownloadViewHolder(override val containerView: View) : RecyclerView.ViewHo
     stop.setOnClickListener {
       itemClickListener.invoke(downloadItem)
     }
-    downloadState.text = toReadableState(downloadItem.downloadState, containerView.context)
-    eta.text = downloadItem.eta.takeIf { it.seconds > 0L }?.toHumanReadableTime() ?: ""
-  }
-
-  private fun toReadableState(
-    downloadState: DownloadState,
-    context: Context
-  ) = when (downloadState) {
-    is Failed -> context.getString(
-      downloadState.stringId,
-      downloadState.reason.name
-    )
-    Pending,
-    Running,
-    Paused,
-    Successful -> context.getString(downloadState.stringId)
+    downloadState.text = downloadItem.downloadState.toReadableState(containerView.context)
+    eta.text = downloadItem.readableEta
   }
 }

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/DeleteFiles.kt

@@ -20,6 +20,7 @@ package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
 
 import android.app.Activity
 import org.kiwix.kiwixmobile.R
+import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.core.dao.NewBookDao
 import org.kiwix.kiwixmobile.core.extensions.toast
 import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/None.kt

@@ -19,6 +19,7 @@
 package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
 
 import android.app.Activity
+import org.kiwix.kiwixmobile.core.base.SideEffect
 
 object None : SideEffect<Unit> {
   override fun invokeWith(activity: Activity) {

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/OpenFile.kt

@@ -20,12 +20,14 @@ package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
 import android.app.Activity
 import androidx.core.net.toUri
 import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.core.extensions.start
 import org.kiwix.kiwixmobile.core.extensions.toast
 import org.kiwix.kiwixmobile.core.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
 import org.kiwix.kiwixmobile.main.KiwixMainActivity
 
-class OpenFile(private val bookOnDisk: BookOnDisk) : SideEffect<Unit> {
+class OpenFile(private val bookOnDisk: BookOnDisk) :
+  SideEffect<Unit> {
 
   override fun invokeWith(activity: Activity) {
     val file = bookOnDisk.file

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/ShareFiles.kt

@@ -24,9 +24,11 @@ import android.net.Uri
 import android.os.Build
 import androidx.core.content.FileProvider
 import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.core.zim_manager.fileselect_view.adapter.BooksOnDiskListItem.BookOnDisk
 
-class ShareFiles(private val selectedBooks: List<BookOnDisk>) : SideEffect<Unit> {
+class ShareFiles(private val selectedBooks: List<BookOnDisk>) :
+  SideEffect<Unit> {
   override fun invokeWith(activity: Activity) {
     val selectedFileShareIntent = Intent()
     selectedFileShareIntent.action = Intent.ACTION_SEND_MULTIPLE

app/src/main/java/org/kiwix/kiwixmobile/zim_manager/fileselect_view/effects/StartMultiSelection.kt

@@ -22,6 +22,7 @@ import android.app.Activity
 import android.view.ActionMode
 import io.reactivex.processors.PublishProcessor
 import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.core.extensions.startActionMode
 import org.kiwix.kiwixmobile.core.zim_manager.fileselect_view.adapter.BooksOnDiskListItem
 import org.kiwix.kiwixmobile.zim_manager.ZimManageViewModel.FileSelectActions

buildSrc/src/main/kotlin/plugin/AllProjectConfigurer.kt

@@ -143,6 +143,7 @@ class AllProjectConfigurer {
       implementation(Libs.kotlin_stdlib_jdk7)
       implementation(Libs.appcompat)
       implementation(Libs.material)
+      implementation(Libs.constraintlayout)
       implementation(Libs.androidx_multidex_multidex)
       implementation(Libs.okhttp)
       implementation(Libs.logging_interceptor)

core/build.gradle

@@ -46,8 +46,6 @@ dependencies {
 
   // Android Support
   implementation(Libs.cardview)
-  implementation(Libs.constraintlayout)
-
 
   // Tab indicator
   implementation(Libs.ink_page_indicator)

core/src/main/AndroidManifest.xml

@@ -21,10 +21,10 @@
     android:hardwareAccelerated="true"
     android:icon="@mipmap/kiwix_icon"
     android:label="@string/app_name"
-    android:usesCleartextTraffic="true"
     android:roundIcon="@mipmap/kiwix_icon_round"
     android:supportsRtl="true"
     android:theme="@style/AppTheme"
+    android:usesCleartextTraffic="true"
     tools:targetApi="m">
 
     <activity
@@ -35,6 +35,7 @@
         <action android:name="android.intent.action.MAIN" />
 
         <category android:name="android.intent.category.LAUNCHER" />
+        <category android:name="android.intent.category.DEFAULT" />
         <category android:name="android.intent.category.MONKEY" />
       </intent-filter>
 

core/src/main/java/org/kiwix/kiwixmobile/core/ViewModelFactory.java

@@ -0,0 +1,55 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.core;
+
+import androidx.lifecycle.ViewModel;
+import androidx.lifecycle.ViewModelProvider;
+import java.util.Map;
+import javax.inject.Provider;
+
+public class ViewModelFactory implements ViewModelProvider.Factory {
+  private final Map<Class<? extends ViewModel>, Provider<ViewModel>> creators;
+
+  public ViewModelFactory(
+    Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
+    this.creators = creators;
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public <T extends ViewModel> T create(Class<T> modelClass) {
+    Provider<? extends ViewModel> creator = creators.get(modelClass);
+    if (creator == null) {
+      for (Map.Entry<Class<? extends ViewModel>, Provider<ViewModel>> entry : creators.entrySet()) {
+        if (modelClass.isAssignableFrom(entry.getKey())) {
+          creator = entry.getValue();
+          break;
+        }
+      }
+    }
+    if (creator == null) {
+      throw new IllegalArgumentException("unknown model class " + modelClass);
+    }
+    try {
+      return (T) creator.get();
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+  }
+}

core/src/main/java/org/kiwix/kiwixmobile/core/base/SideEffect.kt

@@ -15,7 +15,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  *
  */
-package org.kiwix.kiwixmobile.zim_manager.fileselect_view.effects
+package org.kiwix.kiwixmobile.core.base
 
 import android.app.Activity
 

core/src/main/java/org/kiwix/kiwixmobile/core/downloader/model/DownloadItem.kt

@@ -17,6 +17,7 @@
  */
 package org.kiwix.kiwixmobile.core.downloader.model
 
+import android.content.Context
 import com.tonyodev.fetch2.Error
 import com.tonyodev.fetch2.Status
 import com.tonyodev.fetch2.Status.ADDED
@@ -43,6 +44,8 @@ data class DownloadItem(
   val downloadState: DownloadState
 ) {
 
+  val readableEta: CharSequence = eta.takeIf { it.seconds > 0L }?.toHumanReadableTime() ?: ""
+
   constructor(downloadModel: DownloadModel) : this(
     downloadModel.downloadId,
     Base64String(downloadModel.book.favicon),
@@ -84,4 +87,12 @@ sealed class DownloadState(val stringId: Int) {
   data class Failed(val reason: Error) : DownloadState(R.string.failed_state)
 
   override fun toString(): String = javaClass.simpleName
+
+  fun toReadableState(context: Context): CharSequence = when (this) {
+    is Failed -> context.getString(stringId, reason.name)
+    Pending,
+    Running,
+    Paused,
+    Successful -> context.getString(stringId)
+  }
 }

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

@@ -0,0 +1,27 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.core.extensions
+
+import android.widget.ViewAnimator
+
+fun ViewAnimator.setDistinctDisplayedChild(index: Int) {
+  if (displayedChild != index) {
+    displayedChild = index
+  }
+}

core/src/main/java/org/kiwix/kiwixmobile/core/main/CoreMainActivity.java

@@ -1091,8 +1091,7 @@ public abstract class CoreMainActivity extends BaseActivity implements WebViewCa
     @NonNull String[] permissions, @NonNull int[] grantResults) {
     switch (requestCode) {
       case REQUEST_STORAGE_PERMISSION: {
-        if (grantResults.length > 0
-          && grantResults[0] == PERMISSION_GRANTED) {
+        if (hasPermission(Manifest.permission.READ_EXTERNAL_STORAGE)) {
           finish();
           Intent newZimFile = Intents.internal(CoreMainActivity.class);
           newZimFile.setData(Uri.fromFile(file));
@@ -1222,7 +1221,6 @@ public abstract class CoreMainActivity extends BaseActivity implements WebViewCa
     }, 300);
   }
 
-
   @OnClick(R2.id.bottom_toolbar_bookmark)
   public void toggleBookmark() {
     //Check maybe need refresh
@@ -1605,7 +1603,7 @@ public abstract class CoreMainActivity extends BaseActivity implements WebViewCa
     return true;
   }
 
-  protected boolean urlIsInvalid(){
+  protected boolean urlIsInvalid() {
     return getCurrentWebView().getUrl() == null;
   }
 
@@ -1827,14 +1825,10 @@ public abstract class CoreMainActivity extends BaseActivity implements WebViewCa
   }
 
   private void searchFiles() {
-    if (Build.VERSION.SDK_INT >= VERSION_CODES.M && ContextCompat.checkSelfPermission(this,
-      Manifest.permission.READ_EXTERNAL_STORAGE)
-      != PERMISSION_GRANTED) {
-      ActivityCompat.requestPermissions(this,
-        new String[] { Manifest.permission.READ_EXTERNAL_STORAGE },
-        REQUEST_READ_STORAGE_PERMISSION);
-    } else {
+    if (hasPermission(Manifest.permission.READ_EXTERNAL_STORAGE)) {
       scanStorageForZims();
+    } else {
+      requestExternalStoragePermission();
     }
   }
 

core/src/main/res/values/styles.xml

@@ -53,6 +53,7 @@
     <item name="android:textColorSecondary">@color/textDarkSecondary</item>
     <item name="android:textColorTertiary">@color/textDarkTertiary</item>
     <item name="colorControlNormal">@color/accent</item>
+    <item name="buttonStyle">@style/KiwixButtonStyle</item>
   </style>
 
   <style name="AppTheme.Night" parent="AppTheme.Base">
@@ -162,4 +163,8 @@
     <item name="layout_constraintBottom_toBottomOf">parent</item>
   </style>
 
+  <style name="KiwixButtonStyle" parent="Widget.MaterialComponents.Button">
+    <item name="android:textAppearance">@style/TextAppearance.AppCompat.Medium</item>
+  </style>
+
 </resources>

custom/build.gradle

@@ -109,6 +109,7 @@ android {
           buildConfigField "int", "CONTENT_VERSION_CODE", "$parsedJson.version_code"
         }
         buildConfigField "String", "ENFORCED_LANG", "\"$parsedJson.enforced_lang\""
+        buildConfigField "String", "ZIM_URL", "\"$parsedJson.zim_url\""
         resValue "string", "app_name", "$parsedJson.app_name"
         resValue "string", "app_search_string", "Search " + "$parsedJson.app_name"
       }

custom/src/customexample/AndroidManifest.xml

@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-  xmlns:tools="http://schemas.android.com/tools">
-
-  <uses-permission
-    android:name="android.permission.INTERNET"
-    tools:node="remove" />
-</manifest>

custom/src/customexample/info.json

@@ -3,7 +3,8 @@
   "package": "org.kiwix.kiwixcustomexample",
   "version_name": "2017-07",
   "version_code": "1",
-  "zim_file": "wikipedia_fr_test_2017-07.zim",
+  "zim_file": "kiwix.granbluefantasy_en_all_all.zim",
+  "zim_url": "http://download.kiwix.org/zim/other/granbluefantasy_en_all_nopic_2018-10.zim.meta4",
   "embed_zim": false,
   "ic_launcher": "icon.png",
   "enforced_lang": "en"

custom/src/main/AndroidManifest.xml

@@ -39,5 +39,6 @@
         <category android:name="android.intent.category.DEFAULT" />
       </intent-filter>
     </activity>
+    <activity android:name=".download.CustomDownloadActivity" />
   </application>
 </manifest>

custom/src/main/java/org/kiwix/kiwixmobile/custom/CustomViewModelFactory.java

@@ -0,0 +1,35 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom;
+
+import androidx.lifecycle.ViewModel;
+import java.util.Map;
+import javax.inject.Inject;
+import javax.inject.Provider;
+import org.kiwix.kiwixmobile.core.ViewModelFactory;
+import org.kiwix.kiwixmobile.custom.di.CustomScope;
+
+@CustomScope
+public class CustomViewModelFactory extends ViewModelFactory {
+
+  @Inject
+  public CustomViewModelFactory(Map<Class<? extends ViewModel>, Provider<ViewModel>> creators) {
+    super(creators);
+  }
+}

custom/src/main/java/org/kiwix/kiwixmobile/custom/di/CustomActivityComponent.kt

@@ -22,6 +22,7 @@ import android.app.Activity
 import dagger.BindsInstance
 import dagger.Subcomponent
 import org.kiwix.kiwixmobile.core.di.ActivityScope
+import org.kiwix.kiwixmobile.custom.download.CustomDownloadActivity
 import org.kiwix.kiwixmobile.custom.main.CustomMainActivity
 import org.kiwix.kiwixmobile.custom.settings.CustomSettingsActivity
 
@@ -30,6 +31,7 @@ import org.kiwix.kiwixmobile.custom.settings.CustomSettingsActivity
 interface CustomActivityComponent {
   fun inject(customMainActivity: CustomMainActivity)
   fun inject(customSettingsActivity: CustomSettingsActivity)
+  fun inject(customDownloadActivity: CustomDownloadActivity)
 
   @Subcomponent.Builder
   interface Builder {

custom/src/main/java/org/kiwix/kiwixmobile/custom/di/CustomComponent.kt

@@ -21,7 +21,7 @@ package org.kiwix.kiwixmobile.custom.di
 import dagger.Component
 import org.kiwix.kiwixmobile.core.di.components.CoreComponent
 
-@Component(dependencies = [CoreComponent::class])
+@Component(dependencies = [CoreComponent::class], modules = [CustomViewModelModule::class])
 @CustomScope
 interface CustomComponent {
   fun activityComponentBuilder(): CustomActivityComponent.Builder

custom/src/main/java/org/kiwix/kiwixmobile/custom/di/CustomViewModelModule.kt

@@ -0,0 +1,40 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.di
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import dagger.Binds
+import dagger.Module
+import dagger.multibindings.IntoMap
+import org.kiwix.kiwixmobile.custom.CustomViewModelFactory
+import org.kiwix.kiwixmobile.custom.download.CustomDownloadViewModel
+import org.kiwix.kiwixmobile.di.ViewModelKey
+
+@Module
+abstract class CustomViewModelModule {
+  @Binds
+  @IntoMap
+  @ViewModelKey(CustomDownloadViewModel::class)
+  abstract fun bindCustomDownloadViewModel(zimManageViewModel: CustomDownloadViewModel): ViewModel
+
+  @Binds
+  abstract fun bindViewModelFactory(factory: CustomViewModelFactory):
+    ViewModelProvider.Factory
+}

custom/src/main/java/org/kiwix/kiwixmobile/custom/download/Action.kt

@@ -0,0 +1,27 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.download
+
+import org.kiwix.kiwixmobile.core.downloader.model.DownloadItem
+
+sealed class Action {
+  data class DatabaseEmission(val downloads: List<DownloadItem>) : Action()
+  object ClickedDownload : Action()
+  object ClickedRetry : Action()
+}

custom/src/main/java/org/kiwix/kiwixmobile/custom/download/CustomDownloadActivity.kt

@@ -0,0 +1,99 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.download
+
+import android.os.Bundle
+import androidx.lifecycle.Observer
+import androidx.lifecycle.ViewModelProvider
+import io.reactivex.disposables.CompositeDisposable
+import kotlinx.android.synthetic.main.activity_custom_download.cd_view_animator
+import kotlinx.android.synthetic.main.layout_custom_download_error.cd_error_text
+import kotlinx.android.synthetic.main.layout_custom_download_error.cd_retry_button
+import kotlinx.android.synthetic.main.layout_custom_download_in_progress.cd_download_state
+import kotlinx.android.synthetic.main.layout_custom_download_in_progress.cd_eta
+import kotlinx.android.synthetic.main.layout_custom_download_in_progress.cd_progress
+import kotlinx.android.synthetic.main.layout_custom_download_required.cd_download_button
+import org.kiwix.kiwixmobile.core.base.BaseActivity
+import org.kiwix.kiwixmobile.core.downloader.model.DownloadItem
+import org.kiwix.kiwixmobile.core.extensions.setDistinctDisplayedChild
+import org.kiwix.kiwixmobile.core.extensions.viewModel
+import org.kiwix.kiwixmobile.custom.R
+import org.kiwix.kiwixmobile.custom.customActivityComponent
+import org.kiwix.kiwixmobile.custom.download.Action.ClickedDownload
+import org.kiwix.kiwixmobile.custom.download.Action.ClickedRetry
+import org.kiwix.kiwixmobile.custom.download.State.DownloadComplete
+import org.kiwix.kiwixmobile.custom.download.State.DownloadFailed
+import org.kiwix.kiwixmobile.custom.download.State.DownloadInProgress
+import org.kiwix.kiwixmobile.custom.download.State.DownloadRequired
+import javax.inject.Inject
+
+class CustomDownloadActivity : BaseActivity() {
+
+  private val downloadViewModel by lazy {
+    viewModel<CustomDownloadViewModel>(viewModelFactory)
+  }
+
+  @Inject lateinit var viewModelFactory: ViewModelProvider.Factory
+
+  private val compositeDisposable = CompositeDisposable()
+
+  override fun injection() {
+    customActivityComponent.inject(this)
+  }
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    setContentView(R.layout.activity_custom_download)
+    downloadViewModel.state.observe(this, Observer(::render))
+    compositeDisposable.add(
+      downloadViewModel.effects.subscribe(
+        { it.invokeWith(this) },
+        Throwable::printStackTrace
+      )
+    )
+    cd_download_button.setOnClickListener { downloadViewModel.actions.offer(ClickedDownload) }
+    cd_retry_button.setOnClickListener { downloadViewModel.actions.offer(ClickedRetry) }
+  }
+
+  override fun onDestroy() {
+    super.onDestroy()
+    compositeDisposable.clear()
+  }
+
+  private fun render(state: State) {
+    return when (state) {
+      DownloadRequired -> cd_view_animator.setDistinctDisplayedChild(0)
+      is DownloadInProgress -> {
+        cd_view_animator.setDistinctDisplayedChild(1)
+        render(state.downloads[0])
+      }
+      is DownloadFailed -> {
+        cd_view_animator.setDistinctDisplayedChild(2)
+        cd_error_text.text = state.downloadState.toReadableState(this)
+      }
+      DownloadComplete -> cd_view_animator.setDistinctDisplayedChild(3)
+    }
+  }
+
+  private fun render(downloadItem: DownloadItem) {
+    cd_progress.progress = downloadItem.progress
+    cd_eta.text = downloadItem.readableEta
+    cd_download_state.text = downloadItem.downloadState.toReadableState(this)
+  }
+}

custom/src/main/java/org/kiwix/kiwixmobile/custom/download/CustomDownloadViewModel.kt

@@ -0,0 +1,96 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.download
+
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import io.reactivex.disposables.CompositeDisposable
+import io.reactivex.processors.PublishProcessor
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.dao.FetchDownloadDao
+import org.kiwix.kiwixmobile.core.downloader.model.DownloadItem
+import org.kiwix.kiwixmobile.core.downloader.model.DownloadState.Failed
+import org.kiwix.kiwixmobile.custom.download.Action.ClickedDownload
+import org.kiwix.kiwixmobile.custom.download.Action.ClickedRetry
+import org.kiwix.kiwixmobile.custom.download.Action.DatabaseEmission
+import org.kiwix.kiwixmobile.custom.download.State.DownloadComplete
+import org.kiwix.kiwixmobile.custom.download.State.DownloadFailed
+import org.kiwix.kiwixmobile.custom.download.State.DownloadInProgress
+import org.kiwix.kiwixmobile.custom.download.State.DownloadRequired
+import org.kiwix.kiwixmobile.custom.download.effects.DownloadCustom
+import org.kiwix.kiwixmobile.custom.download.effects.FinishAndStartMain
+import org.kiwix.kiwixmobile.custom.download.effects.SetPreferredStorageWithMostSpace
+import javax.inject.Inject
+
+class CustomDownloadViewModel @Inject constructor(
+  downloadDao: FetchDownloadDao,
+  setPreferredStorageWithMostSpace: SetPreferredStorageWithMostSpace,
+  private val downloadCustom: DownloadCustom
+) : ViewModel() {
+
+  val state = MutableLiveData<State>().apply { value = DownloadRequired }
+  val actions = PublishProcessor.create<Action>()
+  private val _effects = PublishProcessor.create<SideEffect<*>>()
+  val effects = _effects.startWith(setPreferredStorageWithMostSpace)
+
+  private val compositeDisposable = CompositeDisposable()
+
+  init {
+    compositeDisposable.addAll(
+      reducer(),
+      downloadsAsActions(downloadDao)
+    )
+  }
+
+  private fun reducer() = actions.map { reduce(it, state.value!!) }
+    .distinctUntilChanged()
+    .subscribe(state::postValue, Throwable::printStackTrace)
+
+  private fun downloadsAsActions(downloadDao: FetchDownloadDao) =
+    downloadDao.downloads()
+      .map { it.map(::DownloadItem) }
+      .subscribe(
+        { actions.offer(DatabaseEmission(it)) },
+        Throwable::printStackTrace
+      )
+
+  private fun reduce(action: Action, state: State): State {
+    return when (action) {
+      is DatabaseEmission -> reduceDatabaseEmission(state, action)
+      ClickedRetry,
+      ClickedDownload -> state.also { _effects.offer(downloadCustom) }
+    }
+  }
+
+  private fun reduceDatabaseEmission(state: State, action: DatabaseEmission) = when (state) {
+    is DownloadFailed,
+    DownloadRequired ->
+      if (action.downloads.isNotEmpty()) DownloadInProgress(action.downloads)
+      else state
+    is DownloadInProgress ->
+      if (action.downloads.isNotEmpty())
+        if (action.downloads[0].downloadState is Failed)
+          DownloadFailed(action.downloads[0].downloadState)
+        else
+          DownloadInProgress(action.downloads)
+      else
+        DownloadComplete.also { _effects.offer(FinishAndStartMain()) }
+    DownloadComplete -> state
+  }
+}

custom/src/main/java/org/kiwix/kiwixmobile/custom/download/State.kt

@@ -0,0 +1,29 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.download
+
+import org.kiwix.kiwixmobile.core.downloader.model.DownloadItem
+import org.kiwix.kiwixmobile.core.downloader.model.DownloadState
+
+sealed class State {
+  object DownloadRequired : State()
+  data class DownloadInProgress(val downloads: List<DownloadItem>) : State()
+  data class DownloadFailed(val downloadState: DownloadState) : State()
+  object DownloadComplete : State()
+}

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

@@ -0,0 +1,63 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.download.effects
+
+import android.app.Activity
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.downloader.Downloader
+import org.kiwix.kiwixmobile.core.entity.LibraryNetworkEntity.Book
+import org.kiwix.kiwixmobile.custom.BuildConfig
+import javax.inject.Inject
+
+data class DownloadCustom @Inject constructor(val downloader: Downloader) : SideEffect<Unit> {
+  override fun invokeWith(activity: Activity) {
+    downloader.download(emptyBook(id = "custom", url = BuildConfig.ZIM_URL))
+  }
+
+  private fun emptyBook(
+    id: String = "",
+    title: String = "",
+    description: String = "",
+    language: String = "",
+    creator: String = "",
+    publisher: String = "",
+    date: String = "",
+    url: String = "",
+    articleCount: String = "",
+    mediaCount: String = "",
+    size: String = "",
+    name: String = "",
+    favIcon: String = ""
+  ) =
+    Book().apply {
+      this.id = id
+      this.title = title
+      this.description = description
+      this.language = language
+      this.creator = creator
+      this.publisher = publisher
+      this.date = date
+      this.url = url
+      this.articleCount = articleCount
+      this.mediaCount = mediaCount
+      this.size = size
+      bookName = name
+      favicon = favIcon
+    }
+}

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

@@ -0,0 +1,31 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.download.effects
+
+import android.app.Activity
+import org.kiwix.kiwixmobile.core.base.SideEffect
+import org.kiwix.kiwixmobile.core.extensions.start
+import org.kiwix.kiwixmobile.custom.main.CustomMainActivity
+
+class FinishAndStartMain() : SideEffect<Unit> {
+  override fun invokeWith(activity: Activity) {
+    activity.finish()
+    activity.start<CustomMainActivity>()
+  }
+}

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

@@ -0,0 +1,38 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.download.effects
+
+import android.app.Activity
+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
+import javax.inject.Inject
+
+class SetPreferredStorageWithMostSpace @Inject constructor(
+  private val storageCalculator: StorageCalculator,
+  private val sharedPreferenceUtil: SharedPreferenceUtil
+) : SideEffect<Unit> {
+  override fun invokeWith(activity: Activity) {
+    ContextCompat.getExternalFilesDirs(activity, null)
+      .filterNotNull()
+      .maxBy(storageCalculator::availableBytes)
+      ?.let { sharedPreferenceUtil.putPrefStorage(it.path) }
+  }
+}

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

@@ -0,0 +1,65 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2019 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/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.custom.main
+
+import android.content.Context
+import androidx.core.content.ContextCompat
+import org.kiwix.kiwixmobile.custom.main.ValidationState.HasBothFiles
+import org.kiwix.kiwixmobile.custom.main.ValidationState.HasFile
+import org.kiwix.kiwixmobile.custom.main.ValidationState.HasNothing
+import java.io.File
+import javax.inject.Inject
+
+class CustomFileValidator @Inject constructor(private val context: Context) {
+
+  fun validate(onFilesFound: (ValidationState) -> Unit, onNoFilesFound: () -> Unit) =
+    when (val installationState = detectInstallationState()) {
+      is HasBothFiles,
+      is HasFile -> onFilesFound(installationState)
+      HasNothing -> onNoFilesFound()
+    }
+
+  private fun detectInstallationState(
+    obbFiles: List<File> = obbFiles(),
+    zimFiles: List<File> = zimFiles()
+  ): ValidationState {
+    return when {
+      obbFiles.isNotEmpty() && zimFiles().isNotEmpty() -> HasBothFiles(obbFiles[0], zimFiles[0])
+      obbFiles.isNotEmpty() -> HasFile(obbFiles[0])
+      zimFiles.isNotEmpty() -> HasFile(zimFiles[0])
+      else -> HasNothing
+    }
+  }
+
+  private fun obbFiles() = scanDirs(ContextCompat.getObbDirs(context), "obb")
+
+  private fun zimFiles() =
+    scanDirs(ContextCompat.getExternalFilesDirs(context, null), "zim")
+
+  private fun scanDirs(dirs: Array<out File>, extensionToMatch: String): List<File> =
+    dirs.fold(listOf()) { acc, dir ->
+      acc + dir.walk().filter { it.extension.startsWith(extensionToMatch) }.toList()
+    }
+}
+
+sealed class ValidationState {
+  data class HasBothFiles(val obbFile: File, val zimFile: File) : ValidationState()
+  data class HasFile(val file: File) : ValidationState()
+  object HasNothing : ValidationState()
+}

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

@@ -22,23 +22,24 @@ import android.content.Intent
 import android.os.Bundle
 import android.util.Log
 import android.view.Menu
-import androidx.appcompat.app.AlertDialog
-import androidx.core.net.toUri
 import org.kiwix.kiwixmobile.core.CoreApp
 import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.extensions.start
 import org.kiwix.kiwixmobile.core.main.CoreMainActivity
 import org.kiwix.kiwixmobile.core.main.WebViewCallback
 import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer
-import org.kiwix.kiwixmobile.core.utils.Constants.TAG_KIWIX
 import org.kiwix.kiwixmobile.core.utils.LanguageUtils
-import org.kiwix.kiwixmobile.core.utils.StyleUtils.dialogStyle
-import org.kiwix.kiwixmobile.core.utils.files.FileUtils
 import org.kiwix.kiwixmobile.custom.BuildConfig
 import org.kiwix.kiwixmobile.custom.customActivityComponent
+import org.kiwix.kiwixmobile.custom.download.CustomDownloadActivity
+import org.kiwix.kiwixmobile.custom.main.ValidationState.HasBothFiles
+import org.kiwix.kiwixmobile.custom.main.ValidationState.HasFile
 import java.io.File
 import java.util.Locale
+import javax.inject.Inject
 
 class CustomMainActivity : CoreMainActivity() {
+  @Inject lateinit var customFileValidator: CustomFileValidator
 
   override fun showHomePage() {
     Log.e("CustomMain", "tried to show home page")
@@ -54,17 +55,22 @@ class CustomMainActivity : CoreMainActivity() {
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
-    Log.d(TAG_KIWIX, "This is a custom app:$packageName")
-    if (loadCustomAppContent()) {
-      Log.d(TAG_KIWIX, "Found custom content, continuing...")
-      // Continue
-    } else {
-      Log.e(TAG_KIWIX, "Problem finding the content, no more OnCreate() code")
-      // What should we do here? exit? I'll investigate empirically.
-      // It seems unpredictable behaviour if the code returns at this point as yesterday
-      // it didn't crash yet today the app crashes because it tries to load books
-      // in onResume();
-    }
+    requireEnforcedLanguage()
+    customFileValidator.validate(
+      {
+        when (it) {
+          is HasFile -> openZimFile(it.file)
+          is HasBothFiles -> {
+            it.zimFile.delete()
+            openZimFile(it.obbFile)
+          }
+        }
+      },
+      {
+        finish()
+        start<CustomDownloadActivity>()
+      }
+    )
   }
 
   override fun onCreateOptionsMenu(menu: Menu?): Boolean {
@@ -79,74 +85,15 @@ class CustomMainActivity : CoreMainActivity() {
     zimReaderContainer: ZimReaderContainer
   ) = CustomWebViewClient(webViewCallback, zimReaderContainer)
 
-  /**
-   * loadCustomAppContent  Return true if all's well, else false.
-   */
-  private fun loadCustomAppContent(): Boolean {
-    Log.d(
-      TAG_KIWIX,
-      "Kiwix Custom App starting for the first time. Checking Companion ZIM: " +
-        BuildConfig.ZIM_FILE_NAME
-    )
-
+  private fun requireEnforcedLanguage(): Boolean {
     val currentLocaleCode = Locale.getDefault().toString()
-    // Custom App recommends to start off a specific language
-    if (BuildConfig.ENFORCED_LANG.length > 0 && BuildConfig.ENFORCED_LANG != currentLocaleCode) {
-
-      // change the locale machinery
+    if (BuildConfig.ENFORCED_LANG.isNotEmpty() && BuildConfig.ENFORCED_LANG != currentLocaleCode) {
       LanguageUtils.handleLocaleChange(this, BuildConfig.ENFORCED_LANG)
-
-      // save new locale into preferences for next startup
       sharedPreferenceUtil.putPrefLanguage(BuildConfig.ENFORCED_LANG)
-
-      // restart activity for new locale to take effect
-      this.setResult(1236)
-      this.finish()
-      this.startActivity(Intent(this, this.javaClass))
-      return false
-    }
-
-    var filePath = ""
-    if (BuildConfig.HAS_EMBEDDED_ZIM) {
-      val appPath = packageResourcePath
-      val libDir = File(appPath.substring(0, appPath.lastIndexOf("/")) + "/lib/")
-      if (libDir.exists() && libDir.listFiles().size > 0) {
-        filePath = libDir.listFiles()[0].path + "/" + BuildConfig.ZIM_FILE_NAME
-      }
-      if (filePath.isEmpty() || !File(filePath).exists()) {
-        filePath = String.format(
-          "/data/data/%s/lib/%s", packageName,
-          BuildConfig.ZIM_FILE_NAME
-        )
-      }
-    } else {
-      filePath = generateExpansionFilePath()
-    }
-
-    Log.d(TAG_KIWIX, "BuildConfig.ZIM_FILE_SIZE = " + BuildConfig.ZIM_FILE_SIZE)
-    if (!FileUtils.doesFileExist(filePath, BuildConfig.ZIM_FILE_SIZE, false)) {
-
-      val zimFileMissingBuilder = AlertDialog.Builder(this, dialogStyle())
-      zimFileMissingBuilder.setTitle(R.string.app_name)
-      zimFileMissingBuilder.setMessage(R.string.custom_app_missing_content)
-      zimFileMissingBuilder.setIcon(R.mipmap.kiwix_icon)
-      val activity = this
-      zimFileMissingBuilder.setPositiveButton(
-        getString(R.string.go_to_play_store)
-      ) { dialog, which ->
-        startActivity(Intent(Intent.ACTION_VIEW).apply {
-          data = "market://details?id=$packageName".toUri()
-        })
-        activity.finish()
-      }
-      zimFileMissingBuilder.setCancelable(false)
-      val zimFileMissingDialog = zimFileMissingBuilder.create()
-      zimFileMissingDialog.show()
-      return false
-    } else {
-      openZimFile(File(filePath))
+      startActivity(Intent(this, this.javaClass))
       return true
     }
+    return false
   }
 
   override fun manageZimFiles(tab: Int) {

custom/src/main/res/layout/activity_custom_download.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
+  android:layout_width="match_parent"
+  android:layout_height="match_parent"
+  android:animateLayoutChanges="true">
+
+  <ImageView
+    android:id="@+id/cd_icon"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:layout_marginTop="@dimen/activity_vertical_margin"
+    android:src="@drawable/kiwix_icon_with_title"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toTopOf="parent" />
+
+  <ViewAnimator
+    android:id="@+id/cd_view_animator"
+    android:layout_width="0dp"
+    android:layout_height="0dp"
+    android:inAnimation="@anim/fade_in"
+    android:outAnimation="@anim/fade_out"
+    app:layout_constraintBottom_toBottomOf="parent"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toBottomOf="@+id/cd_icon">
+
+    <include layout="@layout/layout_custom_download_required" />
+
+    <include layout="@layout/layout_custom_download_in_progress" />
+
+    <include layout="@layout/layout_custom_download_error" />
+
+    <include layout="@layout/layout_custom_download_complete" />
+  </ViewAnimator>
+</androidx.constraintlayout.widget.ConstraintLayout>

custom/src/main/res/layout/layout_custom_download_complete.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
+  android:layout_height="match_parent"
+  tools:showIn="@layout/activity_custom_download">
+
+  <TextView
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:gravity="center"
+    android:text="@string/complete"
+    app:layout_constraintBottom_toBottomOf="parent"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toTopOf="parent"
+    app:layout_constraintVertical_bias=".3" />
+</androidx.constraintlayout.widget.ConstraintLayout>

custom/src/main/res/layout/layout_custom_download_error.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
+  android:layout_height="match_parent"
+  tools:showIn="@layout/activity_custom_download">
+
+  <TextView
+    android:id="@+id/cd_error_text"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:gravity="center"
+    app:layout_constraintBottom_toBottomOf="parent"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toTopOf="parent"
+    app:layout_constraintVertical_bias=".3" />
+
+  <Button
+    android:id="@+id/cd_retry_button"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:layout_marginTop="20dp"
+    android:text="@string/retry"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toBottomOf="@+id/cd_error_text" />
+</androidx.constraintlayout.widget.ConstraintLayout>

custom/src/main/res/layout/layout_custom_download_in_progress.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
+  android:layout_width="match_parent"
+  android:layout_height="match_parent">
+
+  <TextView
+    android:id="@+id/cd_download_state"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    app:layout_constraintBottom_toTopOf="@id/cd_progress"
+    app:layout_constraintLeft_toLeftOf="@+id/cd_progress"
+    app:layout_constraintRight_toRightOf="@+id/cd_progress" />
+
+  <ProgressBar
+    android:id="@+id/cd_progress"
+    style="?android:progressBarStyleHorizontal"
+    android:layout_width="200dp"
+    android:layout_height="wrap_content"
+    android:max="100"
+    app:layout_constraintBottom_toBottomOf="parent"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toTopOf="parent"
+    app:layout_constraintVertical_bias=".3" />
+
+  <TextView
+    android:id="@+id/cd_eta"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:layout_marginStart="5dp"
+    android:layout_marginLeft="5dp"
+    app:layout_constraintBottom_toBottomOf="@id/cd_progress"
+    app:layout_constraintStart_toEndOf="@id/cd_progress"
+    app:layout_constraintTop_toTopOf="@id/cd_progress" />
+</androidx.constraintlayout.widget.ConstraintLayout>

custom/src/main/res/layout/layout_custom_download_required.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:app="http://schemas.android.com/apk/res-auto"
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:tools="http://schemas.android.com/tools"
+  android:layout_width="match_parent"
+  android:layout_height="match_parent"
+  tools:showIn="@layout/activity_custom_download">
+
+  <TextView
+    android:id="@+id/cd_text"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:gravity="center"
+    android:text="@string/invalid_installation"
+    app:layout_constraintBottom_toBottomOf="parent"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toTopOf="parent"
+    app:layout_constraintVertical_bias=".3" />
+
+  <Button
+    android:id="@+id/cd_download_button"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:layout_marginTop="20dp"
+    android:text="@string/download"
+    app:layout_constraintLeft_toLeftOf="parent"
+    app:layout_constraintRight_toRightOf="parent"
+    app:layout_constraintTop_toBottomOf="@+id/cd_text" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

custom/src/main/res/values/strings.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<resources>
+  <string name="retry">Retry</string>
+  <string name="download">Download</string>
+  <string name="invalid_installation">Invalid Install. Please Download Zim.\n Ensure WiFi is on and you have enough storage</string>
+  <string name="complete">Complete</string>
+</resources>