Update MediaPreviewV2 to use thumbnail rail & menu items.

app/src/main/java/org/thoughtcrime/securesms/mediapreview/MediaPreviewV2Activity.kt

@@ -1,13 +1,22 @@
 package org.thoughtcrime.securesms.mediapreview
 
+import android.content.Context
 import android.os.Bundle
 import androidx.appcompat.app.AppCompatActivity
+import androidx.appcompat.app.AppCompatDelegate
 import androidx.fragment.app.commit
 import org.thoughtcrime.securesms.R
 
 class MediaPreviewV2Activity : AppCompatActivity(R.layout.activity_mediapreview_v2) {
+
+  override fun attachBaseContext(newBase: Context) {
+    delegate.localNightMode = AppCompatDelegate.MODE_NIGHT_YES
+    super.attachBaseContext(newBase)
+  }
+
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
+    setTheme(R.style.TextSecure_MediaPreview)
     if (savedInstanceState == null) {
       val bundle = Bundle()
       val args = MediaIntentFactory.requireArguments(intent.extras!!)

app/src/main/java/org/thoughtcrime/securesms/mediapreview/MediaPreviewV2Fragment.kt

@@ -1,23 +1,52 @@
 package org.thoughtcrime.securesms.mediapreview
 
+import android.Manifest
+import android.content.ActivityNotFoundException
 import android.content.Context
+import android.content.DialogInterface
+import android.content.Intent
+import android.os.Build
 import android.os.Bundle
+import android.view.Menu
 import android.view.View
+import android.view.ViewGroup
+import android.view.ViewGroup.MarginLayoutParams
+import android.widget.Toast
+import androidx.core.app.ShareCompat
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowInsetsCompat
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
+import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.viewpager2.widget.ViewPager2.OnPageChangeCallback
+import com.google.android.material.appbar.MaterialToolbar
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import com.google.android.material.snackbar.Snackbar
 import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
+import org.signal.core.util.concurrent.SignalExecutors
 import org.signal.core.util.logging.Log
 import org.thoughtcrime.securesms.R
 import org.thoughtcrime.securesms.animation.DepthPageTransformer
+import org.thoughtcrime.securesms.attachments.DatabaseAttachment
 import org.thoughtcrime.securesms.components.ViewBinderDelegate
+import org.thoughtcrime.securesms.conversation.mutiselect.forward.MultiselectForwardFragment
+import org.thoughtcrime.securesms.conversation.mutiselect.forward.MultiselectForwardFragmentArgs
 import org.thoughtcrime.securesms.database.MediaDatabase
 import org.thoughtcrime.securesms.databinding.FragmentMediaPreviewV2Binding
+import org.thoughtcrime.securesms.mediaoverview.MediaOverviewActivity
+import org.thoughtcrime.securesms.mediasend.Media
+import org.thoughtcrime.securesms.mms.GlideApp
+import org.thoughtcrime.securesms.mms.PartAuthority
+import org.thoughtcrime.securesms.permissions.Permissions
 import org.thoughtcrime.securesms.recipients.Recipient
 import org.thoughtcrime.securesms.util.DateUtils
 import org.thoughtcrime.securesms.util.FullscreenHelper
 import org.thoughtcrime.securesms.util.LifecycleDisposable
+import org.thoughtcrime.securesms.util.MediaUtil
+import org.thoughtcrime.securesms.util.SaveAttachmentTask
+import org.thoughtcrime.securesms.util.StorageUtil
 import java.util.Locale
+import java.util.Optional
 
 class MediaPreviewV2Fragment : Fragment(R.layout.fragment_media_preview_v2), MediaPreviewFragment.Events {
   private val TAG = Log.tag(MediaPreviewV2Fragment::class.java)
@@ -35,7 +64,11 @@ class MediaPreviewV2Fragment : Fragment(R.layout.fragment_media_preview_v2), Med
 
   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
     super.onViewCreated(view, savedInstanceState)
-    initializeViewModel()
+
+    val args = MediaIntentFactory.requireArguments(requireArguments())
+
+    initializeViewModel(args)
+    initializeToolbar(binding.toolbar, args)
     binding.mediaPager.offscreenPageLimit = 1
     binding.mediaPager.setPageTransformer(DepthPageTransformer())
     val adapter = MediaPreviewV2Adapter(this)
@@ -47,18 +80,59 @@ class MediaPreviewV2Fragment : Fragment(R.layout.fragment_media_preview_v2), Med
       }
     })
     initializeFullScreenUi()
+    initializeAlbumRail()
+    anchorMarginsToBottomInsets(binding.mediaPreviewDetailsContainer)
     lifecycleDisposable += viewModel.state.distinctUntilChanged().observeOn(AndroidSchedulers.mainThread()).subscribe {
       bindCurrentState(it)
     }
   }
 
-  private fun initializeFullScreenUi() {
+  private fun initializeToolbar(toolbar: MaterialToolbar, args: MediaIntentFactory.MediaPreviewArgs) {
-    fullscreenHelper.configureToolbarLayout(binding.toolbarCutoutSpacer, binding.toolbar)
+    toolbar.setNavigationOnClickListener {
-    fullscreenHelper.hideSystemUI()
+      requireActivity().onBackPressed()
+    }
+
+    binding.toolbar.inflateMenu(R.menu.media_preview)
+
+    // Restricted to API26 because of MemoryFileUtil not supporting lower API levels well
+    binding.toolbar.menu.findItem(R.id.media_preview__share).isVisible = Build.VERSION.SDK_INT >= 26
+
+    if (args.hideAllMedia) {
+      binding.toolbar.menu.findItem(R.id.media_preview__overview).isVisible = false
+    }
   }
 
-  private fun initializeViewModel() {
+  private fun initializeAlbumRail() {
-    val args = MediaIntentFactory.requireArguments(requireArguments())
+    binding.mediaPreviewAlbumRail.itemAnimator = null // Or can crash when set to INVISIBLE while animating by FullscreenHelper https://issuetracker.google.com/issues/148720682
+    binding.mediaPreviewAlbumRail.layoutManager = LinearLayoutManager(requireContext(), LinearLayoutManager.HORIZONTAL, false)
+    binding.mediaPreviewAlbumRail.adapter = MediaRailAdapter(
+      GlideApp.with(this),
+      object : MediaRailAdapter.RailItemListener {
+        override fun onRailItemClicked(distanceFromActive: Int) {
+          binding.mediaPager.currentItem += distanceFromActive
+        }
+
+        override fun onRailItemDeleteClicked(distanceFromActive: Int) {
+          throw UnsupportedOperationException("Callback unsupported.")
+        }
+      },
+      false
+    )
+  }
+
+  private fun initializeFullScreenUi() {
+    fullscreenHelper.configureToolbarLayout(binding.toolbarCutoutSpacer, binding.toolbar)
+    fullscreenHelper.showAndHideWithSystemUI(requireActivity().window, binding.toolbarLayout, binding.mediaPreviewDetailsContainer)
+  }
+
+  private fun initializeViewModel(args: MediaIntentFactory.MediaPreviewArgs) {
+    if (!MediaUtil.isImageType(args.initialMediaType) && !MediaUtil.isVideoType(args.initialMediaType)) {
+      Log.w(TAG, "Unsupported media type sent to MediaPreviewV2Fragment, finishing.")
+      Snackbar.make(binding.root, R.string.MediaPreviewActivity_unssuported_media_type, Snackbar.LENGTH_LONG)
+        .setAction(R.string.MediaPreviewActivity_dismiss_due_to_error) {
+          requireActivity().finish()
+        }.show()
+    }
     viewModel.setShowThread(args.showThread)
     val sorting = MediaDatabase.Sorting.values()[args.sorting]
     viewModel.fetchAttachments(args.initialMediaUri, args.threadId, sorting)
@@ -67,7 +141,11 @@ class MediaPreviewV2Fragment : Fragment(R.layout.fragment_media_preview_v2), Med
   private fun bindCurrentState(currentState: MediaPreviewV2State) {
     when (currentState.loadState) {
       MediaPreviewV2State.LoadState.READY -> bindReadyState(currentState)
-      // INIT, else -> no-op
+      MediaPreviewV2State.LoadState.LOADED -> {
+        bindReadyState(currentState)
+        bindLoadedState(currentState)
+      }
+      else -> null
     }
   }
 
@@ -76,6 +154,58 @@ class MediaPreviewV2Fragment : Fragment(R.layout.fragment_media_preview_v2), Med
     val currentItem: MediaDatabase.MediaRecord = currentState.mediaRecords[currentState.position]
     binding.toolbar.title = getTitleText(currentItem, currentState.showThread)
     binding.toolbar.subtitle = getSubTitleText(currentItem)
+
+    val menu: Menu = binding.toolbar.menu
+    if (currentItem.threadId == MediaIntentFactory.NOT_IN_A_THREAD.toLong()) {
+      menu.findItem(R.id.media_preview__overview).isVisible = false
+      menu.findItem(R.id.delete).isVisible = false
+    }
+
+    binding.toolbar.setOnMenuItemClickListener {
+      when (it.itemId) {
+        R.id.media_preview__overview -> showOverview(currentItem.threadId)
+        R.id.media_preview__forward -> forward(currentItem)
+        R.id.media_preview__share -> share(currentItem)
+        R.id.save -> saveToDisk(currentItem)
+        R.id.delete -> deleteMedia(currentItem)
+        android.R.id.home -> requireActivity().finish()
+        else -> return@setOnMenuItemClickListener false
+      }
+      return@setOnMenuItemClickListener true
+    }
+  }
+
+  /**
+   * These are binding steps that need a reference to the actual fragment within the pager.
+   * This is not available until after a page has been chosen by the ViewPager, and we receive the
+   * {@link OnPageChangeCallback}.
+   */
+  private fun bindLoadedState(currentState: MediaPreviewV2State) {
+    val currentItem: MediaDatabase.MediaRecord = currentState.mediaRecords[currentState.position]
+    val currentFragment: Fragment? = childFragmentManager.findFragmentByTag("f${currentState.position}")
+    val playbackControls = (currentFragment as? MediaPreviewFragment)?.playbackControls
+    val albumThumbnailMedia = currentState.mediaRecords.map { it.toMedia() }
+    val caption = currentItem.attachment?.caption
+    if (albumThumbnailMedia.isEmpty() && caption == null && playbackControls == null) {
+      binding.mediaPreviewDetailsContainer.visibility = View.GONE
+    } else {
+      binding.mediaPreviewDetailsContainer.visibility = View.VISIBLE
+    }
+    binding.mediaPreviewAlbumRail.visibility = if (albumThumbnailMedia.isEmpty()) View.GONE else View.VISIBLE
+    (binding.mediaPreviewAlbumRail.adapter as MediaRailAdapter).setMedia(albumThumbnailMedia, currentState.position)
+    binding.mediaPreviewAlbumRail.smoothScrollToPosition(currentState.position)
+
+    binding.mediaPreviewCaptionContainer.visibility = if (caption == null) View.GONE else View.VISIBLE
+    binding.mediaPreviewCaption.text = caption
+
+    if (playbackControls != null) {
+      val params = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)
+      playbackControls.layoutParams = params
+      binding.mediaPreviewPlaybackControlsContainer.removeAllViews()
+      binding.mediaPreviewPlaybackControlsContainer.addView(playbackControls)
+    } else {
+      binding.mediaPreviewPlaybackControlsContainer.removeAllViews()
+    }
   }
 
   private fun getTitleText(mediaRecord: MediaDatabase.MediaRecord, showThread: Boolean): String {
@@ -112,20 +242,148 @@ class MediaPreviewV2Fragment : Fragment(R.layout.fragment_media_preview_v2), Med
       getString(R.string.MediaPreviewActivity_draft)
     }
 
+  private fun anchorMarginsToBottomInsets(viewToAnchor: View) {
+    ViewCompat.setOnApplyWindowInsetsListener(viewToAnchor) { view: View, windowInsetsCompat: WindowInsetsCompat ->
+      val layoutParams = view.layoutParams as MarginLayoutParams
+      val systemBarInsets = windowInsetsCompat.getInsets(WindowInsetsCompat.Type.systemBars())
+      layoutParams.setMargins(
+        systemBarInsets.left,
+        layoutParams.topMargin,
+        systemBarInsets.right,
+        systemBarInsets.bottom
+      )
+      view.layoutParams = layoutParams
+      windowInsetsCompat
+    }
+  }
+
+  private fun MediaDatabase.MediaRecord.toMedia(): Media? {
+    val attachment = this.attachment
+    val uri = attachment?.uri
+    if (attachment == null || uri == null) {
+      return null
+    }
+
+    return Media(
+      uri,
+      this.contentType,
+      this.date,
+      attachment.width,
+      attachment.height,
+      attachment.size,
+      0,
+      attachment.isBorderless,
+      attachment.isVideoGif,
+      Optional.empty(),
+      Optional.ofNullable(attachment.caption),
+      Optional.empty()
+    )
+  }
+
   override fun singleTapOnMedia(): Boolean {
-    Log.d(TAG, "singleTapOnMedia()")
+    fullscreenHelper.toggleUiVisibility()
     return true
   }
 
   override fun mediaNotAvailable() {
-    Log.d(TAG, "mediaNotAvailable()")
+    Snackbar.make(binding.root, R.string.MediaPreviewActivity_media_no_longer_available, Snackbar.LENGTH_LONG)
+      .setAction(R.string.MediaPreviewActivity_dismiss_due_to_error) {
+        requireActivity().finish()
+      }.show()
   }
 
   override fun onMediaReady() {
     Log.d(TAG, "onMediaReady()")
   }
 
+  private fun showOverview(threadId: Long) {
+    val context = requireContext()
+    context.startActivity(MediaOverviewActivity.forThread(context, threadId))
+  }
+
+  private fun forward(mediaItem: MediaDatabase.MediaRecord) {
+    val attachment = mediaItem.attachment
+    val uri = attachment?.uri
+    if (attachment != null && uri != null) {
+      MultiselectForwardFragmentArgs.create(
+        requireContext(),
+        mediaItem.threadId,
+        uri,
+        attachment.contentType
+      ) { args: MultiselectForwardFragmentArgs ->
+        MultiselectForwardFragment.showBottomSheet(childFragmentManager, args)
+      }
+    }
+  }
+
+  private fun share(mediaItem: MediaDatabase.MediaRecord) {
+    val attachment = mediaItem.attachment
+    val uri = attachment?.uri
+    if (attachment != null && uri != null) {
+      val publicUri = PartAuthority.getAttachmentPublicUri(uri)
+      val mimeType = Intent.normalizeMimeType(attachment.contentType)
+      val shareIntent = ShareCompat.IntentBuilder(requireActivity())
+        .setStream(publicUri)
+        .setType(mimeType)
+        .createChooserIntent()
+        .addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+
+      try {
+        startActivity(shareIntent)
+      } catch (e: ActivityNotFoundException) {
+        Log.w(TAG, "No activity existed to share the media.", e)
+        Toast.makeText(requireContext(), R.string.MediaPreviewActivity_cant_find_an_app_able_to_share_this_media, Toast.LENGTH_LONG).show()
+      }
+    }
+  }
+
+  private fun saveToDisk(mediaItem: MediaDatabase.MediaRecord) {
+    SaveAttachmentTask.showWarningDialog(requireContext()) { _: DialogInterface?, _: Int ->
+      if (StorageUtil.canWriteToMediaStore()) {
+        performSaveToDisk(mediaItem)
+        return@showWarningDialog
+      }
+      Permissions.with(this)
+        .request(Manifest.permission.WRITE_EXTERNAL_STORAGE)
+        .ifNecessary()
+        .withPermanentDenialDialog(getString(R.string.MediaPreviewActivity_signal_needs_the_storage_permission_in_order_to_write_to_external_storage_but_it_has_been_permanently_denied))
+        .onAnyDenied { Toast.makeText(requireContext(), R.string.MediaPreviewActivity_unable_to_write_to_external_storage_without_permission, Toast.LENGTH_LONG).show() }
+        .onAllGranted { performSaveToDisk(mediaItem) }
+        .execute()
+    }
+  }
+
+  fun performSaveToDisk(mediaItem: MediaDatabase.MediaRecord) {
+    val saveTask = SaveAttachmentTask(requireContext())
+    val saveDate = if (mediaItem.date > 0) mediaItem.date else System.currentTimeMillis()
+    val attachment = mediaItem.attachment
+    val uri = attachment?.uri
+    if (attachment != null && uri != null) {
+      saveTask.executeOnExecutor(SignalExecutors.BOUNDED_IO, SaveAttachmentTask.Attachment(uri, attachment.contentType, saveDate, null))
+    }
+  }
+
+  private fun deleteMedia(mediaItem: MediaDatabase.MediaRecord) {
+    val attachment: DatabaseAttachment = mediaItem.attachment ?: return
+
+    MaterialAlertDialogBuilder(requireContext())
+      .setIcon(R.drawable.ic_warning)
+      .setTitle(R.string.MediaPreviewActivity_media_delete_confirmation_title)
+      .setMessage(R.string.MediaPreviewActivity_media_delete_confirmation_message)
+      .setCancelable(true)
+      .setPositiveButton(R.string.delete) { _, _ ->
+        viewModel.deleteItem(requireContext(), attachment, onSuccess = {
+          requireActivity().finish()
+        }, onError = {
+          Log.e(TAG, "Delete failed!", it)
+          requireActivity().finish()
+        })
+      }
+      .setNegativeButton(android.R.string.cancel, null)
+      .show()
+  }
+
   companion object {
-    val ARGS_KEY: String = "args"
+    const val ARGS_KEY: String = "args"
   }
 }

app/src/main/java/org/thoughtcrime/securesms/mediapreview/MediaPreviewV2State.kt

@@ -8,5 +8,5 @@ data class MediaPreviewV2State(
   val position: Int = 0,
   val showThread: Boolean = false
 ) {
-  enum class LoadState { INIT, READY, }
+  enum class LoadState { INIT, READY, LOADED }
 }

app/src/main/java/org/thoughtcrime/securesms/mediapreview/MediaPreviewV2ViewModel.kt

@@ -1,13 +1,19 @@
 package org.thoughtcrime.securesms.mediapreview
 
+import android.content.Context
 import android.net.Uri
 import androidx.lifecycle.ViewModel
 import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
 import io.reactivex.rxjava3.core.Flowable
+import io.reactivex.rxjava3.core.Single
 import io.reactivex.rxjava3.disposables.CompositeDisposable
+import io.reactivex.rxjava3.functions.Consumer
 import io.reactivex.rxjava3.kotlin.plusAssign
+import io.reactivex.rxjava3.schedulers.Schedulers
 import org.signal.core.util.logging.Log
+import org.thoughtcrime.securesms.attachments.DatabaseAttachment
 import org.thoughtcrime.securesms.database.MediaDatabase
+import org.thoughtcrime.securesms.util.AttachmentUtil
 import org.thoughtcrime.securesms.util.rx.RxStore
 
 class MediaPreviewV2ViewModel : ViewModel() {
@@ -19,7 +25,8 @@ class MediaPreviewV2ViewModel : ViewModel() {
   val state: Flowable<MediaPreviewV2State> = store.stateFlowable.observeOn(AndroidSchedulers.mainThread())
 
   fun fetchAttachments(startingUri: Uri, threadId: Long, sorting: MediaDatabase.Sorting) {
-    disposables += store.update(repository.getAttachments(startingUri, threadId, sorting)) { mediaRecords: List<MediaDatabase.MediaRecord>, oldState: MediaPreviewV2State ->
+    disposables += store.update(repository.getAttachments(startingUri, threadId, sorting)) {
+      mediaRecords: List<MediaDatabase.MediaRecord>, oldState: MediaPreviewV2State ->
       oldState.copy(
         mediaRecords = mediaRecords,
         loadState = MediaPreviewV2State.LoadState.READY
@@ -35,10 +42,17 @@ class MediaPreviewV2ViewModel : ViewModel() {
 
   fun setCurrentPage(position: Int) {
     store.update { oldState ->
-      oldState.copy(position = position)
+      oldState.copy(position = position, loadState = MediaPreviewV2State.LoadState.LOADED)
     }
   }
 
+  fun deleteItem(context: Context, attachment: DatabaseAttachment, onSuccess: Consumer<in Unit>, onError: Consumer<in Throwable>) {
+    disposables += Single.fromCallable { AttachmentUtil.deleteAttachment(context.applicationContext, attachment) }
+      .subscribeOn(Schedulers.io())
+      .observeOn(AndroidSchedulers.mainThread())
+      .subscribe(onSuccess, onError)
+  }
+
   override fun onCleared() {
     disposables.dispose()
     store.dispose()

app/src/main/res/layout/activity_mediapreview_v2.xml

@@ -3,4 +3,5 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/fragment_container_view"
     android:layout_width="match_parent"
-    android:layout_height="match_parent" />
+    android:layout_height="match_parent"
+    android:background="@color/signal_dark_colorNeutral"/>

app/src/main/res/layout/fragment_media_preview_v2.xml

@@ -1,11 +1,67 @@
 <?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<androidx.coordinatorlayout.widget.CoordinatorLayout 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:background="@color/core_grey_95"
+    xmlns:tools="http://schemas.android.com/tools"
-    android:theme="@style/TextSecure.MediaPreview">
+    android:background="@color/signal_dark_colorNeutral">
+    <androidx.viewpager2.widget.ViewPager2
+        android:id="@+id/media_pager"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:clickable="true"
+        android:focusable="true" />
 
+    <LinearLayout
+        android:id="@+id/media_preview_details_container"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="bottom"
+        android:animateLayoutChanges="true"
+        android:background="@drawable/image_preview_shade"
+        android:gravity="bottom"
+        android:orientation="vertical"
+        android:visibility="gone"
+        tools:visibility="visible">
+
+        <org.thoughtcrime.securesms.components.MaxHeightScrollView
+            android:id="@+id/media_preview_caption_container"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:paddingTop="32dp"
+            android:animateLayoutChanges="true"
+            app:scrollView_maxHeight="120dp">
+
+            <org.thoughtcrime.securesms.components.emoji.EmojiTextView
+                android:id="@+id/media_preview_caption"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:paddingStart="16dp"
+                android:paddingEnd="16dp"
+                android:paddingBottom="8dp"
+                style="@style/Signal.Text.Body"
+                android:textColor="@color/core_white"
+                android:gravity="bottom"
+                tools:text="With great power comes great responsibility." />
+
+        </org.thoughtcrime.securesms.components.MaxHeightScrollView>
+
+        <androidx.recyclerview.widget.RecyclerView
+            android:id="@+id/media_preview_album_rail"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="8dp"
+            android:layout_marginStart="12dp"
+            android:layout_marginEnd="12dp"
+            tools:layout_height="64dp"/>
+
+        <FrameLayout
+            android:id="@+id/media_preview_playback_controls_container"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:animateLayoutChanges="true"/>
+
+    </LinearLayout>
     <com.google.android.material.appbar.AppBarLayout
         android:id="@+id/toolbar_layout"
         android:layout_width="match_parent"
@@ -19,18 +75,14 @@
             android:layout_height="0dp"
             android:visibility="gone" />
 
-        <androidx.appcompat.widget.Toolbar
+        <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/toolbar"
             android:theme="?actionBarStyle"
             android:layout_width="match_parent"
             android:layout_height="?attr/actionBarSize"
-            android:background="@android:color/transparent" />
+            android:background="@android:color/transparent"
+            app:navigationIcon="@drawable/ic_arrow_left_white_24" />
 
     </com.google.android.material.appbar.AppBarLayout>
-    <androidx.viewpager2.widget.ViewPager2
+
-        android:id="@+id/media_pager"
+</androidx.coordinatorlayout.widget.CoordinatorLayout>
-        android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        android:clickable="true"
-        android:focusable="true" />
-</FrameLayout>

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

@@ -1965,6 +1965,7 @@
     <string name="MediaPreviewActivity_s_to_you">%1$s to you</string>
     <string name="MediaPreviewActivity_media_no_longer_available">Media no longer available.</string>
     <string name="MediaPreviewActivity_cant_find_an_app_able_to_share_this_media">Can\'t find an app able to share this media.</string>
+    <string name="MediaPreviewActivity_dismiss_due_to_error">Close</string>
 
     <!-- MessageNotifier -->
     <string name="MessageNotifier_d_new_messages_in_d_conversations">%1$d new messages in %2$d conversations</string>