Add RecyclerView dividers

Add divider decorations to the RecyclerView

app/src/main/java/org/oxycblt/auxio/MainActivity.kt

@@ -3,7 +3,6 @@ package org.oxycblt.auxio
 import android.os.Bundle
 import android.util.Log
 import androidx.appcompat.app.AppCompatActivity
-import androidx.appcompat.app.AppCompatDelegate
 
 class MainActivity : AppCompatActivity() {
 
@@ -11,7 +10,7 @@ class MainActivity : AppCompatActivity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 
-        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
+        // AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
 
         Log.d(this::class.simpleName, "Activity Created.")
     }

app/src/main/java/org/oxycblt/auxio/library/LibraryFragment.kt

@@ -12,6 +12,7 @@ import androidx.lifecycle.ViewModelProvider
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentLibraryBinding
 import org.oxycblt.auxio.library.recycler.AlbumDataAdapter
+import org.oxycblt.auxio.recycler.applyDivider
 
 class LibraryFragment : Fragment() {
 
@@ -30,6 +31,7 @@ class LibraryFragment : Fragment() {
 
         val adapter = AlbumDataAdapter()
         binding.libraryRecycler.adapter = adapter
+        binding.libraryRecycler.applyDivider()
 
         libraryModel.albums.observe(
             viewLifecycleOwner,

app/src/main/java/org/oxycblt/auxio/recycler/AlbumViewHolder.kt

@@ -15,7 +15,7 @@ class AlbumViewHolder(
 
         if (album.cover == null) {
             // If there is no cover, clear the ImageView so that the previous
-            // View's cover doesnt stick around.
+            // View's cover doesn't stick around.
             binding.cover.setImageResource(android.R.color.transparent)
         } else {
             binding.cover.setImageBitmap(album.cover)

app/src/main/java/org/oxycblt/auxio/recycler/RecyclerUtils.kt

@@ -1,7 +1,13 @@
 package org.oxycblt.auxio.recycler
 
+import android.graphics.drawable.ColorDrawable
 import android.widget.TextView
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.core.content.ContextCompat
+import androidx.core.graphics.ColorUtils
 import androidx.databinding.BindingAdapter
+import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.models.Album
 
@@ -13,3 +19,31 @@ fun TextView.numSongsToText(album: Album) {
         context.getString(R.string.format_multi_song_count, album.numSongs.toString())
     }
 }
+
+// Apply a custom vertical divider
+fun RecyclerView.applyDivider() {
+    val div = DividerItemDecoration(
+        context,
+        DividerItemDecoration.VERTICAL
+    )
+
+    div.setDrawable(
+        ColorDrawable(
+            getDividerColor(this)
+        )
+    )
+
+    addItemDecoration(div)
+}
+
+private fun getDividerColor(recycler: RecyclerView): Int {
+    val isDark = AppCompatDelegate.getDefaultNightMode() == AppCompatDelegate.MODE_NIGHT_YES
+
+    // Depending on the theme use a different opacity for the divider
+    val alpha = if (isDark) 45 else 85
+
+    return ColorUtils.setAlphaComponent(
+        ContextCompat.getColor(recycler.context, R.color.blue),
+        alpha
+    )
+}

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

@@ -13,12 +13,12 @@
     <androidx.constraintlayout.widget.ConstraintLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:padding="@dimen/padding_small">
+        android:padding="@dimen/padding_medium">
 
         <ImageView
             android:id="@+id/cover"
-            android:layout_width="@dimen/cover_size"
+            android:layout_width="@dimen/cover_size_compact"
-            android:layout_height="@dimen/cover_size"
+            android:layout_height="@dimen/cover_size_compact"
             android:contentDescription="@{@string/description_cover_art + album.title}"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
@@ -32,7 +32,7 @@
             android:id="@+id/album_name"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:layout_marginStart="@dimen/margin_small"
+            android:layout_marginStart="@dimen/margin_medium"
             android:text="@{album.title}"
             android:textAppearance="?android:attr/textAppearanceListItem"
             android:textColor="?android:attr/textColorPrimary"
@@ -46,7 +46,7 @@
             android:id="@+id/song_count"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:layout_marginStart="@dimen/margin_small"
+            android:layout_marginStart="@dimen/margin_medium"
             android:textAppearance="?android:attr/textAppearanceListItemSecondary"
             android:textColor="?android:attr/textColorSecondary"
             app:layout_constraintBottom_toBottomOf="parent"

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

@@ -2,8 +2,10 @@
 <resources>
     <dimen name="padding_tiny">4dp</dimen>
     <dimen name="padding_small">8dp</dimen>
+    <dimen name="padding_medium">16dp</dimen>
 
     <dimen name="margin_small">8dp</dimen>
+    <dimen name="margin_medium">16dp</dimen>
 
     <dimen name="cover_size">64dp</dimen>
     <dimen name="cover_size_compact">42dp</dimen>