MangaController: Title fixes (#5879)

* MangaController: Move toolbar's TextView reference to ElevationAppBarLayout

* MangaController: Update title alpha earlier when exiting

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaController.kt

@@ -14,13 +14,11 @@ import android.view.MenuInflater
 import android.view.MenuItem
 import android.view.View
 import android.view.ViewGroup
-import android.widget.TextView
 import androidx.annotation.FloatRange
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.view.ActionMode
 import androidx.core.os.bundleOf
 import androidx.core.view.WindowInsetsCompat
-import androidx.core.view.children
 import androidx.core.view.doOnLayout
 import androidx.core.view.isVisible
 import androidx.core.view.updateLayoutParams
@@ -94,6 +92,7 @@ import eu.kanade.tachiyomi.util.view.getCoordinates
 import eu.kanade.tachiyomi.util.view.shrinkOnScroll
 import eu.kanade.tachiyomi.util.view.snack
 import eu.kanade.tachiyomi.widget.materialdialogs.QuadStateTextView
+import kotlinx.coroutines.cancel
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import reactivecircus.flowbinding.recyclerview.scrollEvents
@@ -148,8 +147,6 @@ class MangaController :
     private val preferences: PreferencesHelper by injectLazy()
     private val coverCache: CoverCache by injectLazy()
 
-    private var toolbarTextView: TextView? = null
-
     private var mangaInfoAdapter: MangaInfoHeaderAdapter? = null
     private var chaptersHeaderAdapter: MangaChaptersHeaderAdapter? = null
     private var chaptersAdapter: ChaptersAdapter? = null
@@ -198,6 +195,10 @@ class MangaController :
         // Hide toolbar title on enter
         if (type.isEnter) {
             updateToolbarTitleAlpha()
+        } else {
+            // Cancel listeners early
+            viewScope.cancel()
+            updateToolbarTitleAlpha(1F)
         }
     }
 
@@ -344,11 +345,7 @@ class MangaController :
 
     private fun updateToolbarTitleAlpha(@FloatRange(from = 0.0, to = 1.0) alpha: Float? = null) {
         val scrolledList = binding.fullRecycler ?: binding.infoRecycler!!
-        if (toolbarTextView == null) {
-            toolbarTextView = (activity as? MainActivity)?.binding?.toolbar?.children
-                ?.find { it is TextView } as? TextView
-        }
-        toolbarTextView?.alpha = when {
+        (activity as? MainActivity)?.binding?.appbar?.titleTextAlpha = when {
             // Specific alpha provided
             alpha != null -> alpha
 
@@ -412,8 +409,6 @@ class MangaController :
         chaptersAdapter = null
         settingsSheet = null
         addSnackbar?.dismiss()
-        updateToolbarTitleAlpha(1F)
-        toolbarTextView = null
         super.onDestroyView(view)
     }
 

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

@@ -3,10 +3,19 @@ package eu.kanade.tachiyomi.widget
 import android.animation.ValueAnimator
 import android.content.Context
 import android.util.AttributeSet
+import android.widget.TextView
+import androidx.annotation.FloatRange
+import androidx.lifecycle.coroutineScope
+import androidx.lifecycle.findViewTreeLifecycleOwner
 import com.google.android.material.animation.AnimationUtils
 import com.google.android.material.appbar.AppBarLayout
 import com.google.android.material.appbar.MaterialToolbar
 import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.util.view.findChild
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import reactivecircus.flowbinding.android.view.HierarchyChangeEvent
+import reactivecircus.flowbinding.android.view.hierarchyChangeEvents
 
 class ElevationAppBarLayout @JvmOverloads constructor(
     context: Context,
@@ -18,6 +27,19 @@ class ElevationAppBarLayout @JvmOverloads constructor(
 
     private val toolbar by lazy { findViewById<MaterialToolbar>(R.id.toolbar) }
 
+    @FloatRange(from = 0.0, to = 1.0)
+    var titleTextAlpha = 1F
+        set(value) {
+            field = value
+            titleTextView?.alpha = field
+        }
+
+    private var titleTextView: TextView? = null
+        set(value) {
+            field = value
+            field?.alpha = titleTextAlpha
+        }
+
     private var elevationAnimator: ValueAnimator? = null
     private var backgroundAlphaAnimator: ValueAnimator? = null
 
@@ -63,6 +85,29 @@ class ElevationAppBarLayout @JvmOverloads constructor(
         }
     }
 
+    override fun onAttachedToWindow() {
+        super.onAttachedToWindow()
+        titleTextView = toolbar.findChild<TextView>()
+        findViewTreeLifecycleOwner()?.lifecycle?.coroutineScope?.let { scope ->
+            toolbar.hierarchyChangeEvents()
+                .onEach {
+                    when (it) {
+                        is HierarchyChangeEvent.ChildAdded -> {
+                            if (it.child is TextView) {
+                                titleTextView = it.child as TextView
+                            }
+                        }
+                        is HierarchyChangeEvent.ChildRemoved -> {
+                            if (it.child == titleTextView) {
+                                titleTextView = null
+                            }
+                        }
+                    }
+                }
+                .launchIn(scope)
+        }
+    }
+
     private fun updateBackgroundAlpha() {
         val newTransparent = if (lifted) false else isTransparentWhenNotLifted
         if (transparent != newTransparent) {