issue 2890: Add an "ALT" sticker to the media preview container (#2942)

* issue 2890: Add an "ALT" sticker to the media preview container if there are descriptions

* issue 2890: Use end and start for positioning

* issue 2890: Adapt to new media view group

* issue 2890: Use an indicator overlay for every (single) preview image

* issue 2890: Reduce radius to match that of the preview layout

* issue 2890: Remove (again) unused code

* issue 2890: Set visibility in any case

* issue 2890: Use a translatable text for ALT

* issue 2890: Show ALT flag only when showing media

* issue 2890: Call doOnLayout on the layout wrapper

app/src/main/java/com/keylesspalace/tusky/adapter/StatusBaseViewHolder.java

@@ -411,14 +411,15 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
         return ImageLoadingHelper.decodeBlurHash(this.avatar.getContext(), blurhash);
     }
 
-    private void loadImage(MediaPreviewImageView imageView,
+    private void loadImage(View wrapper,
+                           MediaPreviewImageView imageView,
                            @Nullable String previewUrl,
                            @Nullable MetaData meta,
                            @Nullable String blurhash) {
 
         Drawable placeholder = blurhash != null ? decodeBlurHash(blurhash) : mediaPreviewUnloaded;
 
-        ViewKt.doOnLayout(imageView, view -> {
+        ViewKt.doOnLayout(wrapper, view -> {
             if (TextUtils.isEmpty(previewUrl)) {
                 imageView.removeFocalPoint();
 
@@ -433,7 +434,7 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
                 if (focus != null) { // If there is a focal point for this attachment:
                     imageView.setFocalPoint(focus);
 
-                    Glide.with(imageView)
+                    Glide.with(imageView.getContext())
                             .load(previewUrl)
                             .placeholder(placeholder)
                             .centerInside()
@@ -460,19 +461,21 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
         mediaPreview.setVisibility(View.VISIBLE);
         mediaPreview.setAspectRatios(AttachmentHelper.aspectRatios(attachments));
 
-        mediaPreview.forEachIndexed((i, imageView) -> {
+        mediaPreview.forEachIndexed((i, wrapper, imageView, descriptionIndicator) -> {
             Attachment attachment = attachments.get(i);
             String previewUrl = attachment.getPreviewUrl();
             String description = attachment.getDescription();
+            boolean hasDescription = !TextUtils.isEmpty(description);
 
-            if (TextUtils.isEmpty(description)) {
+            if (hasDescription) {
-                imageView.setContentDescription(imageView.getContext()
-                        .getString(R.string.action_view_media));
-            } else {
                 imageView.setContentDescription(description);
+            } else {
+                imageView.setContentDescription(imageView.getContext().getString(R.string.action_view_media));
             }
+            descriptionIndicator.setVisibility(hasDescription ? View.VISIBLE : View.GONE);
 
             loadImage(
+                    wrapper,
                     imageView,
                     showingContent ? previewUrl : null,
                     attachment.getMeta(),
@@ -502,6 +505,7 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
                 }
                 v.setVisibility(View.GONE);
                 sensitiveMediaWarning.setVisibility(View.VISIBLE);
+                descriptionIndicator.setVisibility(View.GONE);
             });
             sensitiveMediaWarning.setOnClickListener(v -> {
                 if (getBindingAdapterPosition() != RecyclerView.NO_POSITION) {
@@ -509,6 +513,7 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
                 }
                 v.setVisibility(View.GONE);
                 sensitiveMediaShow.setVisibility(View.VISIBLE);
+                descriptionIndicator.setVisibility(hasDescription ? View.VISIBLE : View.GONE);
             });
 
             return null;

app/src/main/java/com/keylesspalace/tusky/view/MediaPreviewLayout.kt

@@ -2,9 +2,11 @@ package com.keylesspalace.tusky.view
 
 import android.content.Context
 import android.util.AttributeSet
+import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.LinearLayout
+import android.widget.TextView
 import com.keylesspalace.tusky.R
 import kotlin.math.roundToInt
 
@@ -26,7 +28,9 @@ class MediaPreviewLayout(context: Context, attrs: AttributeSet? = null) :
             attachImageViews()
         }
 
-    private val imageViewCache = Array(4) { MediaPreviewImageView(context) }
+    private val imageViewCache = Array(4) {
+        LayoutInflater.from(context).inflate(R.layout.item_image_preview_overlay, this, false)
+    }
 
     private var measuredOrientation = LinearLayout.VERTICAL
 
@@ -180,9 +184,15 @@ class MediaPreviewLayout(context: Context, attrs: AttributeSet? = null) :
         }
     }
 
-    inline fun forEachIndexed(action: (Int, MediaPreviewImageView) -> Unit) {
+    inline fun forEachIndexed(action: (Int, View, MediaPreviewImageView, TextView) -> Unit) {
         for (index in 0 until childCount) {
-            action(index, getChildAt(index) as MediaPreviewImageView)
+            val wrapper = getChildAt(index)
+            action(
+                index,
+                wrapper,
+                wrapper.findViewById(R.id.preview_image_view) as MediaPreviewImageView,
+                wrapper.findViewById(R.id.preview_media_description_indicator) as TextView
+            )
         }
     }
 }

app/src/main/res/drawable/media_warning_bg.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <shape xmlns:android="http://schemas.android.com/apk/res/android">
-    <corners android:radius="8dp" />
+    <corners android:radius="7dp" />
     <solid  android:color="@color/color_background_transparent_60" />
 </shape>

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

@@ -0,0 +1,36 @@
+<?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="wrap_content">
+
+    <com.keylesspalace.tusky.view.MediaPreviewImageView
+        android:id="@+id/preview_image_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:importantForAccessibility="no"
+        tools:ignore="RtlSymmetry"
+        tools:visibility="visible" />
+
+    <TextView
+        android:id="@+id/preview_media_description_indicator"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:textColor="?android:attr/textColorSecondary"
+        android:textSize="?attr/status_text_small"
+        android:background="@drawable/media_warning_bg"
+        android:contentDescription="@null"
+        android:paddingLeft="5dp"
+        android:paddingTop="3dp"
+        android:paddingRight="5dp"
+        android:paddingBottom="3dp"
+        android:layout_margin="3dp"
+        android:visibility="gone"
+        android:text="@string/post_media_alt"
+        app:layout_constraintEnd_toEndOf="@+id/preview_image_view"
+        app:layout_constraintBottom_toBottomOf="@+id/preview_image_view"
+        app:tint="@color/white" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

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

@@ -20,7 +20,7 @@
         android:contentDescription="@null"
         android:padding="@dimen/status_sensitive_media_button_padding"
         android:visibility="gone"
-        app:layout_constraintLeft_toLeftOf="@+id/status_media_preview_container"
+        app:layout_constraintStart_toStartOf="@+id/status_media_preview_container"
         app:layout_constraintTop_toTopOf="@+id/status_media_preview_container"
         app:srcCompat="@drawable/ic_eye_24dp"
         app:tint="@color/white" />

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

@@ -40,6 +40,7 @@
     <string name="post_boosted_format">%s teilte</string>
     <string name="post_sensitive_media_title">Heikle Inhalte</string>
     <string name="post_media_hidden_title">Medien versteckt</string>
+    <string name="post_media_alt">ALT</string>
     <string name="post_sensitive_media_directions">Zum Anzeigen tippen</string>
     <string name="post_content_warning_show_more">Zeige mehr</string>
     <string name="post_content_warning_show_less">Zeige weniger</string>

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

@@ -60,6 +60,7 @@
     <string name="post_boosted_format">%s boosted</string>
     <string name="post_sensitive_media_title">Sensitive content</string>
     <string name="post_media_hidden_title">Media hidden</string>
+    <string name="post_media_alt">ALT</string>
     <string name="post_sensitive_media_directions">Click to view</string>
     <string name="post_content_warning_show_more">Show More</string>
     <string name="post_content_warning_show_less">Show Less</string>