Set status bar foreground when app bar is hidden

app/src/main/java/com/google/android/material/appbar/KotatsuAppBarLayout.kt

@@ -0,0 +1,151 @@
+package com.google.android.material.appbar
+
+import android.animation.AnimatorSet
+import android.animation.ValueAnimator
+import android.annotation.SuppressLint
+import android.content.Context
+import android.util.AttributeSet
+import android.widget.TextView
+import androidx.annotation.FloatRange
+import com.google.android.material.animation.AnimationUtils
+import com.google.android.material.appbar.AppBarLayout.OnOffsetChangedListener
+import com.google.android.material.shape.MaterialShapeDrawable
+import org.koitharu.kotatsu.R
+import com.google.android.material.R as materialR
+
+/**
+ * [AppBarLayout] with our own lift state handler and custom title alpha.
+ *
+ * Inside this package to access some package-private methods.
+ */
+class KotatsuAppBarLayout @JvmOverloads constructor(
+	context: Context,
+	attrs: AttributeSet? = null
+) : AppBarLayout(context, attrs) {
+
+	private var lifted = true
+
+	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 animatorSet: AnimatorSet? = null
+
+	private var statusBarForegroundAnimator: ValueAnimator? = null
+	private val offsetListener = OnOffsetChangedListener { appBarLayout, verticalOffset ->
+		// Show status bar foreground when offset
+		val foreground = (appBarLayout?.statusBarForeground as? MaterialShapeDrawable) ?: return@OnOffsetChangedListener
+		val start = foreground.alpha
+		val end = if (verticalOffset != 0) 255 else 0
+
+		statusBarForegroundAnimator?.cancel()
+		if (animatorSet?.isRunning == true) {
+			foreground.alpha = end
+			return@OnOffsetChangedListener
+		}
+		if (start != end) {
+			statusBarForegroundAnimator = ValueAnimator.ofInt(start, end).apply {
+				duration = resources.getInteger(materialR.integer.app_bar_elevation_anim_duration).toLong()
+				interpolator = AnimationUtils.LINEAR_INTERPOLATOR
+				addUpdateListener {
+					foreground.alpha = it.animatedValue as Int
+				}
+				start()
+			}
+		}
+	}
+
+	var isTransparentWhenNotLifted = false
+		set(value) {
+			if (field != value) {
+				field = value
+				updateStates()
+			}
+		}
+
+	override fun isLiftOnScroll(): Boolean = false
+
+	override fun isLifted(): Boolean = lifted
+
+	override fun setLifted(lifted: Boolean): Boolean {
+		return if (this.lifted != lifted) {
+			this.lifted = lifted
+			updateStates()
+			true
+		} else {
+			false
+		}
+	}
+
+	override fun setLiftedState(lifted: Boolean, force: Boolean): Boolean = false
+
+	override fun onAttachedToWindow() {
+		super.onAttachedToWindow()
+		addOnOffsetChangedListener(offsetListener)
+		toolbar.background.alpha = 0 // Use app bar background
+	}
+
+	override fun onDetachedFromWindow() {
+		super.onDetachedFromWindow()
+		removeOnOffsetChangedListener(offsetListener)
+	}
+
+	@SuppressLint("Recycle")
+	private fun updateStates() {
+		val animators = mutableListOf<ValueAnimator>()
+
+		val fromElevation = elevation
+		val toElevation = if (lifted) {
+			resources.getDimension(materialR.dimen.design_appbar_elevation)
+		} else {
+			0F
+		}
+		if (fromElevation != toElevation) {
+			ValueAnimator.ofFloat(fromElevation, toElevation).apply {
+				addUpdateListener {
+					elevation = it.animatedValue as Float
+					(statusBarForeground as? MaterialShapeDrawable)?.elevation = it.animatedValue as Float
+				}
+				animators.add(this)
+			}
+		}
+
+		val transparent = if (lifted) false else isTransparentWhenNotLifted
+		val fromAlpha = (background as? MaterialShapeDrawable)?.alpha ?: background.alpha
+		val toAlpha = if (transparent) 0 else 255
+		if (fromAlpha != toAlpha) {
+			ValueAnimator.ofInt(fromAlpha, toAlpha).apply {
+				addUpdateListener {
+					val value = it.animatedValue as Int
+					background.alpha = value
+				}
+				animators.add(this)
+			}
+		}
+
+		if (animators.isNotEmpty()) {
+			animatorSet?.cancel()
+			animatorSet = AnimatorSet().apply {
+				duration = resources.getInteger(materialR.integer.app_bar_elevation_anim_duration).toLong()
+				interpolator = AnimationUtils.LINEAR_INTERPOLATOR
+				playTogether(*animators.toTypedArray())
+				start()
+			}
+		}
+	}
+
+	init {
+		statusBarForeground = MaterialShapeDrawable.createWithElevationOverlay(context)
+	}
+}

app/src/main/java/org/koitharu/kotatsu/base/ui/widgets/HideBottomNavigationOnScrollBehavior.kt

@@ -0,0 +1,103 @@
+package org.koitharu.kotatsu.base.ui.widgets
+
+import android.animation.ValueAnimator
+import android.content.Context
+import android.util.AttributeSet
+import android.view.View
+import android.view.ViewGroup
+import android.view.animation.DecelerateInterpolator
+import androidx.appcompat.widget.Toolbar
+import androidx.coordinatorlayout.widget.CoordinatorLayout
+import androidx.core.view.ViewCompat
+import com.google.android.material.appbar.AppBarLayout
+import com.google.android.material.bottomnavigation.BottomNavigationView
+import org.koitharu.kotatsu.utils.ext.animatorDurationScale
+import org.koitharu.kotatsu.utils.ext.findChild
+import kotlin.math.roundToLong
+
+class HideBottomNavigationOnScrollBehavior @JvmOverloads constructor(
+	context: Context? = null,
+	attrs: AttributeSet? = null,
+) : CoordinatorLayout.Behavior<BottomNavigationView>(context, attrs) {
+
+	@ViewCompat.NestedScrollType
+	private var lastStartedType: Int = 0
+
+	private var offsetAnimator: ValueAnimator? = null
+
+	private var dyRatio = 1F
+
+	override fun layoutDependsOn(parent: CoordinatorLayout, child: BottomNavigationView, dependency: View): Boolean {
+		return dependency is AppBarLayout
+	}
+
+	override fun onDependentViewChanged(
+		parent: CoordinatorLayout,
+		child: BottomNavigationView,
+		dependency: View,
+	): Boolean {
+		val toolbarSize = (dependency as ViewGroup).findChild<Toolbar>()?.height ?: 0
+		dyRatio = if (toolbarSize > 0) {
+			child.height.toFloat() / toolbarSize
+		} else {
+			1F
+		}
+		return false
+	}
+
+	override fun onStartNestedScroll(
+		coordinatorLayout: CoordinatorLayout,
+		child: BottomNavigationView,
+		directTargetChild: View,
+		target: View,
+		axes: Int,
+		type: Int,
+	): Boolean {
+		if (axes != ViewCompat.SCROLL_AXIS_VERTICAL) {
+			return false
+		}
+		lastStartedType = type
+		offsetAnimator?.cancel()
+		return true
+	}
+
+	override fun onNestedPreScroll(
+		coordinatorLayout: CoordinatorLayout,
+		child: BottomNavigationView,
+		target: View,
+		dx: Int,
+		dy: Int,
+		consumed: IntArray,
+		type: Int,
+	) {
+		super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type)
+		child.translationY = (child.translationY + (dy * dyRatio)).coerceIn(0F, child.height.toFloat())
+	}
+
+	override fun onStopNestedScroll(
+		coordinatorLayout: CoordinatorLayout,
+		child: BottomNavigationView,
+		target: View,
+		type: Int,
+	) {
+		if (lastStartedType == ViewCompat.TYPE_TOUCH || type == ViewCompat.TYPE_NON_TOUCH) {
+			animateBottomNavigationVisibility(child, child.translationY < child.height / 2)
+		}
+	}
+
+	private fun animateBottomNavigationVisibility(child: BottomNavigationView, isVisible: Boolean) {
+		offsetAnimator?.cancel()
+		offsetAnimator = ValueAnimator().apply {
+			interpolator = DecelerateInterpolator()
+			duration = (150 * child.context.animatorDurationScale).roundToLong()
+			addUpdateListener {
+				child.translationY = it.animatedValue as Float
+			}
+		}
+		offsetAnimator?.setFloatValues(
+			child.translationY,
+			if (isVisible) 0F else child.height.toFloat(),
+		)
+		offsetAnimator?.start()
+	}
+}

app/src/main/java/org/koitharu/kotatsu/base/ui/widgets/KotatsuBottomNavigationView.kt

@@ -0,0 +1,156 @@
+package org.koitharu.kotatsu.base.ui.widgets
+
+import android.animation.Animator
+import android.animation.AnimatorListenerAdapter
+import android.animation.TimeInterpolator
+import android.content.Context
+import android.os.Parcel
+import android.os.Parcelable
+import android.util.AttributeSet
+import android.view.ViewPropertyAnimator
+import androidx.coordinatorlayout.widget.CoordinatorLayout
+import androidx.core.view.doOnLayout
+import androidx.core.view.updateLayoutParams
+import androidx.customview.view.AbsSavedState
+import androidx.interpolator.view.animation.FastOutLinearInInterpolator
+import androidx.interpolator.view.animation.LinearOutSlowInInterpolator
+import androidx.lifecycle.findViewTreeLifecycleOwner
+import androidx.lifecycle.lifecycleScope
+import com.google.android.material.bottomnavigation.BottomNavigationView
+import org.koitharu.kotatsu.utils.ext.applySystemAnimatorScale
+import com.google.android.material.R as materialR
+
+class KotatsuBottomNavigationView @JvmOverloads constructor(
+	context: Context,
+	attrs: AttributeSet? = null,
+	defStyleAttr: Int = materialR.attr.bottomNavigationStyle,
+	defStyleRes: Int = materialR.style.Widget_Design_BottomNavigationView,
+) : BottomNavigationView(context, attrs, defStyleAttr, defStyleRes) {
+
+	private var currentAnimator: ViewPropertyAnimator? = null
+
+	private var currentState = STATE_UP
+
+	init {
+		// Hide on scroll
+		doOnLayout {
+			findViewTreeLifecycleOwner()?.lifecycleScope?.let {
+				updateLayoutParams<CoordinatorLayout.LayoutParams> {
+					behavior = HideBottomNavigationOnScrollBehavior()
+				}
+			}
+		}
+	}
+
+	override fun onSaveInstanceState(): Parcelable {
+		val superState = super.onSaveInstanceState()
+		return SavedState(superState).also {
+			it.currentState = currentState
+			it.translationY = translationY
+		}
+	}
+
+	override fun onRestoreInstanceState(state: Parcelable?) {
+		if (state is SavedState) {
+			super.onRestoreInstanceState(state.superState)
+			super.setTranslationY(state.translationY)
+			currentState = state.currentState
+		} else {
+			super.onRestoreInstanceState(state)
+		}
+	}
+
+	override fun setTranslationY(translationY: Float) {
+		// Disallow translation change when state down
+		if (currentState == STATE_DOWN) return
+		super.setTranslationY(translationY)
+	}
+
+	/**
+	 * Shows this view up.
+	 */
+	fun slideUp() = post {
+		currentAnimator?.cancel()
+		clearAnimation()
+
+		currentState = STATE_UP
+		animateTranslation(
+			0F,
+			SLIDE_UP_ANIMATION_DURATION,
+			LinearOutSlowInInterpolator(),
+		)
+	}
+
+	/**
+	 * Hides this view down. [setTranslationY] won't work until [slideUp] is called.
+	 */
+	fun slideDown() = post {
+		currentAnimator?.cancel()
+		clearAnimation()
+
+		currentState = STATE_DOWN
+		animateTranslation(
+			height.toFloat(),
+			SLIDE_DOWN_ANIMATION_DURATION,
+			FastOutLinearInInterpolator(),
+		)
+	}
+
+	private fun animateTranslation(targetY: Float, duration: Long, interpolator: TimeInterpolator) {
+		currentAnimator = animate()
+			.translationY(targetY)
+			.setInterpolator(interpolator)
+			.setDuration(duration)
+			.applySystemAnimatorScale(context)
+			.setListener(object : AnimatorListenerAdapter() {
+				override fun onAnimationEnd(animation: Animator?) {
+					currentAnimator = null
+					postInvalidate()
+				}
+			},
+			)
+	}
+
+	internal class SavedState : AbsSavedState {
+		var currentState = STATE_UP
+		var translationY = 0F
+
+		constructor(superState: Parcelable) : super(superState)
+
+		constructor(source: Parcel, loader: ClassLoader?) : super(source, loader) {
+			currentState = source.readInt()
+			translationY = source.readFloat()
+		}
+
+		override fun writeToParcel(out: Parcel, flags: Int) {
+			super.writeToParcel(out, flags)
+			out.writeInt(currentState)
+			out.writeFloat(translationY)
+		}
+
+		companion object {
+			@JvmField
+			val CREATOR: Parcelable.ClassLoaderCreator<SavedState> = object : Parcelable.ClassLoaderCreator<SavedState> {
+				override fun createFromParcel(source: Parcel, loader: ClassLoader): SavedState {
+					return SavedState(source, loader)
+				}
+
+				override fun createFromParcel(source: Parcel): SavedState {
+					return SavedState(source, null)
+				}
+
+				override fun newArray(size: Int): Array<SavedState> {
+					return newArray(size)
+				}
+			}
+		}
+	}
+
+	companion object {
+		private const val STATE_DOWN = 1
+		private const val STATE_UP = 2
+
+		private const val SLIDE_UP_ANIMATION_DURATION = 225L
+		private const val SLIDE_DOWN_ANIMATION_DURATION = 175L
+	}
+}

app/src/main/java/org/koitharu/kotatsu/favourites/ui/FavouritesContainerFragment.kt

@@ -81,22 +81,11 @@ class FavouritesContainerFragment :
 	}
 
 	override fun onWindowInsetsChanged(insets: Insets) {
-		val headerHeight = (activity as? AppBarOwner)?.appBar?.measureHeight() ?: insets.top
-		binding.root.updatePadding(
-			top = headerHeight - insets.top
-		)
-		binding.pager.updatePadding(
-			// 8 dp is needed so that the top of the list is not attached to tabs (visible when ActionMode is active)
-			top = -headerHeight + resources.resolveDp(8)
-		)
 		binding.tabs.apply {
 			updatePadding(
 				left = insets.left,
 				right = insets.right
 			)
-			updateLayoutParams<ViewGroup.MarginLayoutParams> {
-				topMargin = insets.top
-			}
 		}
 	}
 

app/src/main/java/org/koitharu/kotatsu/list/ui/MangaListFragment.kt

@@ -185,10 +185,6 @@ abstract class MangaListFragment :
 			right = insets.right,
 		)
 		if (activity is MainActivity) {
-			binding.recyclerView.updatePadding(
-				top = headerHeight,
-				bottom = insets.bottom,
-			)
 			binding.swipeRefreshLayout.setProgressViewOffset(
 				true,
 				headerHeight + resources.resolveDp(-72),

app/src/main/java/org/koitharu/kotatsu/tracker/ui/FeedFragment.kt

@@ -76,12 +76,9 @@ class FeedFragment :
 	}
 
 	override fun onWindowInsetsChanged(insets: Insets) {
-		val headerHeight = (activity as? AppBarOwner)?.appBar?.measureHeight() ?: insets.top
 		binding.recyclerView.updatePadding(
-			top = headerHeight + paddingVertical,
 			left = insets.left + paddingHorizontal,
 			right = insets.right + paddingHorizontal,
-			bottom = insets.bottom + paddingVertical,
 		)
 	}
 

app/src/main/java/org/koitharu/kotatsu/utils/ext/AndroidExt.kt

@@ -9,14 +9,19 @@ import android.net.Network
 import android.net.NetworkRequest
 import android.net.Uri
 import android.os.Build
+import android.provider.Settings
+import android.view.ViewGroup
+import android.view.ViewPropertyAnimator
 import android.view.Window
+import android.view.animation.Animation
 import androidx.activity.result.ActivityResultLauncher
+import androidx.constraintlayout.motion.widget.MotionScene
 import androidx.core.app.ActivityOptionsCompat
+import androidx.core.view.children
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.coroutineScope
 import androidx.work.CoroutineWorker
 import com.google.android.material.elevation.ElevationOverlayProvider
-import kotlin.coroutines.resume
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.channels.trySendBlocking
 import kotlinx.coroutines.delay
@@ -111,4 +116,15 @@ fun Window.setNavigationBarTransparentCompat(context: Context, elevation: Float
 			elevation,
 		)
 	}
+}
+
+val Context.animatorDurationScale: Float
+	get() = Settings.Global.getFloat(this.contentResolver, Settings.Global.ANIMATOR_DURATION_SCALE, 1f)
+
+fun ViewPropertyAnimator.applySystemAnimatorScale(context: Context): ViewPropertyAnimator = apply {
+	this.duration = (this.duration * context.animatorDurationScale).toLong()
+}
+
+inline fun <reified T> ViewGroup.findChild(): T? {
+	return children.find { it is T } as? T
 }

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

@@ -15,7 +15,8 @@
 	<androidx.viewpager2.widget.ViewPager2
 		android:id="@+id/pager"
 		android:layout_width="match_parent"
-		android:layout_height="match_parent" />
+		android:layout_height="match_parent"
+		android:paddingVertical="8dp"/>
 
 	<ViewStub
 		android:id="@+id/stub_empty_state"