Disable elevation in recent chapters. Improve downloads discovery

app/src/main/java/eu/kanade/tachiyomi/ui/recent_updates/RecentChaptersFragment.kt

@@ -17,6 +17,7 @@ import eu.kanade.tachiyomi.ui.main.MainActivity
 import eu.kanade.tachiyomi.ui.reader.ReaderActivity
 import eu.kanade.tachiyomi.util.toast
 import eu.kanade.tachiyomi.widget.DeletingChaptersDialog
+import kotlinx.android.synthetic.main.activity_main.*
 import kotlinx.android.synthetic.main.fragment_recent_chapters.*
 import nucleus.factory.RequiresPresenter
 import timber.log.Timber
@@ -101,13 +102,14 @@ class RecentChaptersFragment:
         setToolbarTitle(R.string.label_recent_updates)
 
         // Disable toolbar elevation, it looks better with sticky headers.
-//        ViewCompat.setElevation(activity.appbar, 0f)
+        activity.appbar.disableElevation()
     }
 
-//    override fun onDestroyView() {
-//        ViewCompat.setElevation(activity.appbar, 4.dpToPx.toFloat())
-//        super.onDestroyView()
-//    }
+    override fun onDestroyView() {
+        // Restore toolbar elevation.
+        activity.appbar.enableElevation()
+        super.onDestroyView()
+    }
 
     /**
      * Returns selected chapters

app/src/main/java/eu/kanade/tachiyomi/ui/recent_updates/RecentChaptersPresenter.kt

@@ -82,8 +82,8 @@ class RecentChaptersPresenter : BasePresenter<RecentChaptersFragment>() {
                         // Find an active download for this chapter.
                         val download = downloadManager.queue.find { it.chapter.id == item.chapter.id }
 
-                        // If there's an active download, assign it, otherwise ask the manager if the chapter is
-                        // downloaded and assign it to the status.
+                        // If there's an active download, assign it, otherwise ask the manager if
+                        // the chapter is downloaded and assign it to the status.
                         if (download != null) {
                             item.download = download
                         }
@@ -126,30 +126,36 @@ class RecentChaptersPresenter : BasePresenter<RecentChaptersFragment>() {
      * @param items the list of chapter from the database.
      */
     private fun setDownloadedChapters(items: List<RecentChapterItem>) {
-        // Cached list of downloaded manga directories.
-        val mangaDirectories = mutableMapOf<Long, Array<UniFile>>()
+        // Cached list of downloaded manga directories. Directory name is also cached because
+        // it's slow when using SAF.
+        val mangaDirsForSource = mutableMapOf<Long, Map<String?, UniFile>>()
 
         // Cached list of downloaded chapter directories for a manga.
-        val chapterDirectories = mutableMapOf<Long, Array<UniFile>>()
+        val chapterDirsForManga = mutableMapOf<Long, Map<String?, UniFile>>()
 
         for (item in items) {
             val manga = item.manga
             val chapter = item.chapter
             val source = sourceManager.get(manga.source) ?: continue
 
-            val mangaDirs = mangaDirectories.getOrPut(source.id) {
-                downloadManager.findSourceDir(source)?.listFiles() ?: emptyArray()
+            // Get the directories for the source of the manga.
+            val dirsForSource = mangaDirsForSource.getOrPut(source.id) {
+                val sourceDir = downloadManager.findSourceDir(source)
+                sourceDir?.listFiles()?.associateBy { it.name }.orEmpty()
             }
 
+            // Get the manga directory in the source or continue.
             val mangaDirName = downloadManager.getMangaDirName(manga)
-            val mangaDir = mangaDirs.find { it.name == mangaDirName } ?: continue
+            val mangaDir = dirsForSource[mangaDirName] ?: continue
 
-            val chapterDirs = chapterDirectories.getOrPut(manga.id!!) {
-                mangaDir.listFiles() ?: emptyArray()
+            // Get the directories for the manga.
+            val chapterDirs = chapterDirsForManga.getOrPut(manga.id!!) {
+                mangaDir.listFiles()?.associateBy { it.name }.orEmpty()
             }
 
+            // Assign the download if the directory exists.
             val chapterDirName = downloadManager.getChapterDirName(chapter)
-            if (chapterDirs.any { it.name == chapterDirName }) {
+            if (chapterDirName in chapterDirs) {
                 item.status = Download.DOWNLOADED
             }
         }

app/src/main/java/eu/kanade/tachiyomi/widget/ElevationAppBarLayout.kt

@@ -0,0 +1,48 @@
+package eu.kanade.tachiyomi.widget
+
+import android.animation.ObjectAnimator
+import android.animation.StateListAnimator
+import android.content.Context
+import android.os.Build
+import android.support.design.R
+import android.support.design.widget.AppBarLayout
+import android.util.AttributeSet
+
+class ElevationAppBarLayout @JvmOverloads constructor(
+        context: Context,
+        attrs: AttributeSet? = null
+) : AppBarLayout(context, attrs) {
+
+    private var origStateAnimator: StateListAnimator? = null
+
+    init {
+        if (Build.VERSION.SDK_INT >= 21) {
+            origStateAnimator = stateListAnimator
+        }
+    }
+
+    fun enableElevation() {
+        if (Build.VERSION.SDK_INT >= 21) {
+            stateListAnimator = origStateAnimator
+        }
+    }
+
+    fun disableElevation() {
+        if (Build.VERSION.SDK_INT >= 21) {
+            stateListAnimator = StateListAnimator().apply {
+                val objAnimator = ObjectAnimator.ofFloat(this, "elevation", 0f)
+
+                // Enabled and collapsible, but not collapsed means not elevated
+                addState(intArrayOf(android.R.attr.enabled, R.attr.state_collapsible, -R.attr.state_collapsed),
+                        objAnimator)
+
+                // Default enabled state
+                addState(intArrayOf(android.R.attr.enabled), objAnimator)
+
+                // Disabled state
+                addState(IntArray(0), objAnimator)
+            }
+        }
+    }
+
+}

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

@@ -12,7 +12,7 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
-        <android.support.design.widget.AppBarLayout
+        <eu.kanade.tachiyomi.widget.ElevationAppBarLayout
             android:id="@+id/appbar"
             android:layout_width="match_parent"
             android:layout_height="wrap_content">
@@ -30,7 +30,7 @@
                 app:tabMode="scrollable"
                 app:tabMinWidth="75dp"/>
 
-        </android.support.design.widget.AppBarLayout>
+        </eu.kanade.tachiyomi.widget.ElevationAppBarLayout>
 
 
         <FrameLayout