Fix part of #136: Topic overview low fi part 2 - Topic Download/Delete [ON HOLD]

app/src/main/java/org/oppia/app/topic/overview/TopicDeleteDialogFragment.kt

@@ -0,0 +1,39 @@
+package org.oppia.app.topic.overview
+
+import android.app.Dialog
+import android.content.Context
+import android.os.Bundle
+import androidx.appcompat.app.AlertDialog
+import androidx.fragment.app.DialogFragment
+import org.oppia.app.R
+
+/**
+ * DialogFragment that confirms whether user wants to delete the topic or not.
+ */
+class TopicDeleteDialogFragment : DialogFragment() {
+  companion object {
+    /**
+     * This function is responsible for displaying content in DialogFragment.
+     *
+     * @return [TopicDeleteDialogFragment]: DialogFragment
+     */
+    fun newInstance(): TopicDeleteDialogFragment {
+      return TopicDeleteDialogFragment()
+    }
+  }
+
+  override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
+    val topicDeleteListener: TopicDeleteListener = parentFragment as TopicOverviewFragment
+
+    return AlertDialog.Builder(activity as Context)
+      .setMessage(R.string.topic_delete_alert_dialog_description)
+      .setPositiveButton(R.string.topic_delete_alert_dialog_delete_button) { dialog, whichButton ->
+        topicDeleteListener.deleteTopic()
+        dismiss()
+      }
+      .setNegativeButton(R.string.topic_delete_alert_dialog_cancel_button) { dialog, whichButton ->
+        dismiss()
+      }
+      .create()
+  }
+}

app/src/main/java/org/oppia/app/topic/overview/TopicDeleteListener.kt

@@ -0,0 +1,6 @@
+package org.oppia.app.topic.overview
+
+/** Interface to confirm whether user wants to delete the topic. */
+interface TopicDeleteListener {
+  fun deleteTopic()
+}

app/src/main/java/org/oppia/app/topic/overview/TopicDownloadDialogFragment.kt

@@ -0,0 +1,46 @@
+package org.oppia.app.topic.overview
+
+import android.app.Dialog
+import android.content.Context
+import android.os.Bundle
+import androidx.appcompat.app.AlertDialog
+import androidx.fragment.app.DialogFragment
+import android.widget.CheckBox
+import org.oppia.app.R
+
+/**
+ * DialogFragment that indicates to the user they are on cellular when trying to download topic.
+ */
+class TopicDownloadDialogFragment : DialogFragment() {
+  companion object {
+    /**
+     * This function is responsible for displaying content in DialogFragment.
+     *
+     * @return [TopicDownloadDialogFragment]: DialogFragment
+     */
+    fun newInstance(): TopicDownloadDialogFragment {
+      return TopicDownloadDialogFragment()
+    }
+  }
+
+  override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
+    val view = activity!!.layoutInflater.inflate(R.layout.topic_download_dialog, /* root= */null)
+    val checkBox = view.findViewById<CheckBox>(R.id.topic_download_dialog_checkbox)
+
+    val topicDownloadListener: TopicDownloadListener = parentFragment as TopicOverviewFragment
+
+    return AlertDialog.Builder(activity as Context)
+      .setTitle(R.string.topic_download_alert_dialog_title)
+      .setView(view)
+      .setMessage(R.string.topic_download_alert_dialog_description)
+      .setPositiveButton(R.string.topic_download_alert_dialog_download_button) { dialog, whichButton ->
+        topicDownloadListener.downloadTopicWhileOnCellular(checkBox.isChecked)
+        dismiss()
+      }
+      .setNegativeButton(R.string.topic_download_alert_dialog_cancel_button) { dialog, whichButton ->
+        topicDownloadListener.doNotDownloadTopicWhileOnCellular(checkBox.isChecked)
+        dismiss()
+      }
+      .create()
+  }
+}

app/src/main/java/org/oppia/app/topic/overview/TopicDownloadListener.kt

@@ -0,0 +1,16 @@
+package org.oppia.app.topic.overview
+
+/** Interface to check the preference regarding alert for [TopicDownloadDialogFragment]. */
+interface TopicDownloadListener {
+  /**
+   * If saveUserChoice is true, download topic and save preference do not show dialog again.
+   * If saveUserChoice is false, download topic and do not save preference and show this dialog next time too.
+   */
+  fun downloadTopicWhileOnCellular(saveUserChoice: Boolean)
+
+  /**
+   * If saveUserChoice is true, do not download topic on cellular network and save preference.
+   * If saveUserChoice is false, do not download topic and do not save preference.
+   */
+  fun doNotDownloadTopicWhileOnCellular(saveUserChoice: Boolean)
+}

app/src/main/java/org/oppia/app/topic/overview/TopicOverviewFragment.kt

@@ -9,7 +9,7 @@ import org.oppia.app.fragment.InjectableFragment
 import javax.inject.Inject
 
 /** Fragment that contains overview of Topic. */
-class TopicOverviewFragment : InjectableFragment() {
+class TopicOverviewFragment : InjectableFragment(), TopicDownloadListener, TopicDeleteListener {
   @Inject
   lateinit var topicOverviewFragmentPresenter: TopicOverviewFragmentPresenter
 
@@ -21,4 +21,16 @@ class TopicOverviewFragment : InjectableFragment() {
   override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
     return topicOverviewFragmentPresenter.handleCreateView(inflater, container)
   }
+
+  override fun downloadTopicWhileOnCellular(saveUserChoice: Boolean) {
+    topicOverviewFragmentPresenter.handleDownloadTopic(saveUserChoice)
+  }
+
+  override fun doNotDownloadTopicWhileOnCellular(saveUserChoice: Boolean) {
+    topicOverviewFragmentPresenter.handleDoNotDownloadTopic(saveUserChoice)
+  }
+
+  override fun deleteTopic() {
+    topicOverviewFragmentPresenter.handleDeleteTopic()
+  }
 }

app/src/main/java/org/oppia/app/topic/overview/TopicOverviewFragmentPresenter.kt

@@ -19,6 +19,9 @@ import org.oppia.util.data.AsyncResult
 import org.oppia.util.logging.Logger
 import javax.inject.Inject
 
+private const val TAG_TOPIC_DELETE_DIALOG = "TOPIC_DELETE_DIALOG"
+private const val TAG_TOPIC_DOWNLOAD_DIALOG = "TOPIC_DOWNLOAD_DIALOG"
+
 /** The presenter for [TopicOverviewFragment]. */
 @FragmentScope
 class TopicOverviewFragmentPresenter @Inject constructor(
@@ -30,7 +33,7 @@ class TopicOverviewFragmentPresenter @Inject constructor(
 ) {
   private val routeToTopicPlayListener = activity as RouteToTopicPlayListener
 
-  private val topicOverviewViewModel  = getTopicOverviewViewModel()
+  private val topicOverviewViewModel = getTopicOverviewViewModel()
 
   fun handleCreateView(inflater: LayoutInflater, container: ViewGroup?): View? {
     val binding = TopicOverviewFragmentBinding.inflate(inflater, container, /* attachToRoot= */ false)
@@ -43,12 +46,48 @@ class TopicOverviewFragmentPresenter @Inject constructor(
     return binding.root
   }
 
+  private fun showTopicDownloadDialogFragment() {
+    val previousFragment = fragment.childFragmentManager.findFragmentByTag(TAG_TOPIC_DOWNLOAD_DIALOG)
+    if (previousFragment != null) {
+      fragment.childFragmentManager.beginTransaction().remove(previousFragment).commitNow()
+    }
+    val dialogFragment = TopicDownloadDialogFragment.newInstance()
+    dialogFragment.showNow(fragment.childFragmentManager, TAG_TOPIC_DOWNLOAD_DIALOG)
+  }
+
+  private fun showTopicDeleteDialogFragment() {
+    val previousFragment = fragment.childFragmentManager.findFragmentByTag(TAG_TOPIC_DELETE_DIALOG)
+    if (previousFragment != null) {
+      fragment.childFragmentManager.beginTransaction().remove(previousFragment).commitNow()
+    }
+    val dialogFragment = TopicDeleteDialogFragment.newInstance()
+    dialogFragment.showNow(fragment.childFragmentManager, TAG_TOPIC_DELETE_DIALOG)
+  }
+
   fun seeMoreClicked(v: View) {
     routeToTopicPlayListener.routeToTopicPlayFragment()
   }
 
-  private fun getTopicOverviewViewModel(): TopicOverviewViewModel {
-    return viewModelProvider.getForFragment(fragment, TopicOverviewViewModel::class.java)
+  fun downloadStatusImageClicked(v: View) {
+    when (topicOverviewViewModel.downloadStatus.get()) {
+      STATUS_NOT_DOWNLOADED -> showTopicDownloadDialogFragment()
+      STATUS_DOWNLOADED -> showTopicDeleteDialogFragment()
+      /** STATUS_DOWNLOADING -> TODO(Rajat): Discuss with Ben regarding this case. */
+    }
+  }
+
+  fun handleDownloadTopic(saveUserChoice: Boolean) {
+    // TODO(Rajat): Save this preference and change icon only when download is finished.
+    topicOverviewViewModel.downloadStatus.set(STATUS_DOWNLOADED)
+  }
+
+  fun handleDoNotDownloadTopic(saveUserChoice: Boolean) {
+    // TODO(Rajat): Save this preference and do not download topic.
+  }
+
+  fun handleDeleteTopic() {
+    // TODO(Rajat): Delete topic from device.
+    topicOverviewViewModel.downloadStatus.set(STATUS_NOT_DOWNLOADED)
   }
 
   private val topicLiveData: LiveData<Topic> by lazy { getTopicList() }
@@ -74,4 +113,8 @@ class TopicOverviewFragmentPresenter @Inject constructor(
     }
     return topic.getOrDefault(Topic.getDefaultInstance())
   }
+
+  private fun getTopicOverviewViewModel(): TopicOverviewViewModel {
+    return viewModelProvider.getForFragment(fragment, TopicOverviewViewModel::class.java)
+  }
 }

app/src/main/java/org/oppia/app/topic/overview/TopicOverviewViewModel.kt

@@ -10,18 +10,25 @@ import org.oppia.app.model.Topic
 import org.oppia.app.viewmodel.ObservableViewModel
 import javax.inject.Inject
 
+const val STATUS_NOT_DOWNLOADED = "STATUS_NOT_DOWNLOADED"
+const val STATUS_DOWNLOADED = "STATUS_DOWNLOADED"
+const val STATUS_DOWNLOADING = "STATUS_DOWNLOADING"
+
 /** [ViewModel] for showing topic overview details. */
 @FragmentScope
 class TopicOverviewViewModel @Inject constructor() : ObservableViewModel() {
   companion object {
     @JvmStatic
     @BindingAdapter("downloadDrawable")
-    fun setBackgroundResource(downloadStatus: ImageView, resource: Int) {
-      downloadStatus.setImageResource(resource)
+    fun setBackgroundResource(downloadImageView: ImageView, downloadStatus: String) {
+      when (downloadStatus) {
+        STATUS_NOT_DOWNLOADED -> downloadImageView.setImageResource(R.drawable.ic_file_download_primary_24dp)
+        STATUS_DOWNLOADED -> downloadImageView.setImageResource(R.drawable.ic_check_circle_primary_24dp)
+        STATUS_DOWNLOADING -> downloadImageView.setImageResource(R.drawable.ic_pause_circle_filled_black_24dp)
+      }
     }
   }
 
   val topic = ObservableField<Topic>(Topic.getDefaultInstance())
-
-  var downloadStatus = ObservableField<Int>(R.drawable.ic_file_download_primary_24dp)
+  var downloadStatus = ObservableField<String>(STATUS_NOT_DOWNLOADED)
 }

app/src/main/res/layout/topic_download_dialog.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  android:layout_width="match_parent"
+  android:layout_height="wrap_content"
+  android:padding="@dimen/cellular_data_dialog_padding">
+  <CheckBox
+    android:id="@+id/topic_download_dialog_checkbox"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical"
+    android:text="@string/cellular_data_alert_dialog_checkbox">
+  </CheckBox>
+</RelativeLayout>

app/src/main/res/layout/topic_overview_fragment.xml

@@ -91,6 +91,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="24dp"
+        android:onClick="@{presenter::downloadStatusImageClicked}"
         android:layout_marginTop="24dp"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/see_more_text_view"/>

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

@@ -23,4 +23,12 @@
   <string name="state_end_exploration_button">RETURN TO TOPIC</string>
   <string name="state_learn_again_button">LEARN AGAIN</string>
   <string name="topic_overview_see_more">See More</string>
+  <string name="topic_download_alert_dialog_download_button">DOWNLOAD NOW</string>
+  <string name="topic_download_alert_dialog_cancel_button">CANCEL</string>
+  <string name="topic_download_alert_dialog_title">Currently on Cellular Data</string>
+  <string name="topic_download_alert_dialog_description">You can fo to Settings to Download only when connected to Wi-Fi.</string>
+  <string name="topic_download_alert_dialog_checkbox">Don\'t show this message again</string>
+  <string name="topic_delete_alert_dialog_delete_button">DELETE</string>
+  <string name="topic_delete_alert_dialog_cancel_button">CANCEL</string>
+  <string name="topic_delete_alert_dialog_description">Delete this topic from the device?</string>
 </resources>