Animating swipe for category hopper

So its more clear that it's swipeable

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryController.kt

@@ -16,6 +16,7 @@ import android.view.LayoutInflater
 import android.view.Menu
 import android.view.MenuInflater
 import android.view.MenuItem
+import android.view.MotionEvent
 import android.view.View
 import android.view.ViewGroup
 import android.view.ViewPropertyAnimator
@@ -194,6 +195,7 @@ class LibraryController(
 
     private var filterTooltip: ViewTooltip? = null
     private var isAnimatingHopper: Boolean? = null
+    private var animatorSet: AnimatorSet? = null
     var hasMovedHopper = preferences.shownHopperSwipeTutorial().get()
     private var shouldScrollToTop = false
     private val showCategoryInTitle
@@ -542,7 +544,7 @@ class LibraryController(
         }
     }
 
-    @SuppressLint("RtlHardcoded")
+    @SuppressLint("RtlHardcoded", "ClickableViewAccessibility")
     private fun setUpHopper() {
         category_hopper_frame.gone()
         down_category.setOnClickListener {
@@ -598,7 +600,18 @@ class LibraryController(
         val gestureDetector = GestureDetectorCompat(activity, LibraryGestureDetector(this))
         listOf(category_hopper_layout, up_category, down_category, category_button).forEach {
             it.setOnTouchListener { _, event ->
-                gestureDetector.onTouchEvent(event)
+                if (event?.action == MotionEvent.ACTION_DOWN) {
+                    animatorSet?.end()
+                }
+                if (event?.action == MotionEvent.ACTION_UP) {
+                    val result = gestureDetector.onTouchEvent(event)
+                    if (!result) {
+                        category_hopper_frame.animate().setDuration(150L).translationX(0f).start()
+                    }
+                    result
+                } else {
+                    gestureDetector.onTouchEvent(event)
+                }
             }
         }
     }
@@ -884,6 +897,7 @@ class LibraryController(
         isAnimatingHopper = true
         val slide = 25f.dpToPx
         val animatorSet = AnimatorSet()
+        this.animatorSet = animatorSet
         val animations = listOf(
             slideAnimation(0f, slide, 200),
             slideAnimation(slide, -slide),
@@ -895,7 +909,9 @@ class LibraryController(
         animatorSet.startDelay = 1250
         animatorSet.addListener(
             EndAnimatorListener {
+                category_hopper_frame.translationX = 0f
                 isAnimatingHopper = false
+                this.animatorSet = null
             }
         )
         animatorSet.start()

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryGestureDetector.kt

@@ -4,12 +4,13 @@ import android.view.GestureDetector
 import android.view.Gravity
 import android.view.MotionEvent
 import androidx.coordinatorlayout.widget.CoordinatorLayout
-import eu.kanade.tachiyomi.ui.main.MainActivity
 import eu.kanade.tachiyomi.util.view.hide
 import eu.kanade.tachiyomi.util.view.updateLayoutParams
 import kotlinx.android.synthetic.main.filter_bottom_sheet.*
 import kotlinx.android.synthetic.main.library_list_controller.*
 import kotlin.math.abs
+import kotlin.math.pow
+import kotlin.math.sign
 
 class LibraryGestureDetector(private val controller: LibraryController) : GestureDetector
 .SimpleOnGestureListener() {
@@ -17,6 +18,22 @@ class LibraryGestureDetector(private val controller: LibraryController) : Gestur
         return false
     }
 
+    override fun onScroll(
+        e1: MotionEvent?,
+        e2: MotionEvent?,
+        distanceX: Float,
+        distanceY: Float
+    ): Boolean {
+        val distance = ((e1?.rawX ?: 0f) - (e2?.rawX ?: 0f)) / 50
+        val poa = 1.7f
+        controller.category_hopper_frame.translationX = abs(distance).pow(poa) * -sign(distance)
+        return super.onScroll(e1, e2, distanceX, distanceY)
+    }
+
+    override fun onSingleTapUp(e: MotionEvent?): Boolean {
+        return super.onSingleTapUp(e)
+    }
+
     override fun onFling(
         e1: MotionEvent,
         e2: MotionEvent,
@@ -26,53 +43,80 @@ class LibraryGestureDetector(private val controller: LibraryController) : Gestur
         var result = false
         val diffY = e2.y - e1.y
         val diffX = e2.x - e1.x
+        val animator = controller.category_hopper_frame.animate().setDuration(150L)
+        animator.translationX(0f)
+        animator.withEndAction {
+            controller.category_hopper_frame.translationX = 0f
+        }
         if (abs(diffX) <= abs(diffY) &&
-            abs(diffY) > MainActivity.SWIPE_THRESHOLD &&
-            abs(velocityY) > MainActivity.SWIPE_VELOCITY_THRESHOLD
+            abs(diffY) > SWIPE_THRESHOLD &&
+            abs(velocityY) > SWIPE_VELOCITY_THRESHOLD
         ) {
             if (diffY <= 0) {
                 controller.showSheet()
             } else {
                 controller.filter_bottom_sheet.sheetBehavior?.hide()
             }
-            result = true
         } else if (abs(diffX) >= abs(diffY) &&
-            abs(diffX) > MainActivity.SWIPE_THRESHOLD * 3 &&
-            abs(velocityX) > MainActivity.SWIPE_VELOCITY_THRESHOLD
+            abs(diffX) > SWIPE_THRESHOLD * 5 &&
+            abs(velocityX) > SWIPE_VELOCITY_THRESHOLD
         ) {
+            val hopperGravity = (controller.category_hopper_frame.layoutParams as CoordinatorLayout.LayoutParams).gravity
             if (diffX <= 0) {
-                controller.category_hopper_frame.updateLayoutParams<CoordinatorLayout.LayoutParams> {
-                    gravity =
-                        Gravity.TOP or (
-                        if (gravity == Gravity.TOP or Gravity.RIGHT) {
-                            controller.preferences.hopperGravity().set(1)
-                            Gravity.CENTER
-                        } else {
-                            controller.preferences.hopperGravity().set(0)
-                            Gravity.LEFT
-                        }
-                        )
+                animator.translationX(
+                    if (hopperGravity == Gravity.TOP or Gravity.LEFT) 0f
+                    else (-(controller.view!!.width - controller.category_hopper_frame.width) / 2).toFloat()
+                ).withEndAction {
+                    controller.category_hopper_frame.updateLayoutParams<CoordinatorLayout.LayoutParams> {
+                        gravity =
+                            Gravity.TOP or (
+                            if (gravity == Gravity.TOP or Gravity.RIGHT) {
+                                controller.preferences.hopperGravity().set(1)
+                                Gravity.CENTER
+                            } else {
+                                controller.preferences.hopperGravity().set(0)
+                                Gravity.LEFT
+                            }
+                            )
+                    }
+                    savePrefs()
                 }
             } else {
-                controller.category_hopper_frame.updateLayoutParams<CoordinatorLayout.LayoutParams> {
-                    gravity =
-                        Gravity.TOP or (
-                        if (gravity == Gravity.TOP or Gravity.LEFT) {
-                            controller.preferences.hopperGravity().set(1)
-                            Gravity.CENTER
-                        } else {
-                            controller.preferences.hopperGravity().set(2)
-                            Gravity.RIGHT
-                        }
-                        )
+                animator.translationX(
+                    if (hopperGravity == Gravity.TOP or Gravity.RIGHT) 0f
+                    else ((controller.view!!.width - controller.category_hopper_frame.width) / 2).toFloat()
+                ).withEndAction {
+                    controller.category_hopper_frame.updateLayoutParams<CoordinatorLayout.LayoutParams> {
+                        gravity =
+                            Gravity.TOP or (
+                            if (gravity == Gravity.TOP or Gravity.LEFT) {
+                                controller.preferences.hopperGravity().set(1)
+                                Gravity.CENTER
+                            } else {
+                                controller.preferences.hopperGravity().set(2)
+                                Gravity.RIGHT
+                            }
+                            )
+                    }
+                    savePrefs()
                 }
             }
-            if (!controller.hasMovedHopper) {
-                controller.preferences.shownHopperSwipeTutorial().set(true)
-            }
-            controller.hopperGravity = controller.preferences.hopperGravity().get()
             result = true
         }
+        animator.start()
         return result
     }
+
+    fun savePrefs() {
+        if (!controller.hasMovedHopper) {
+            controller.preferences.shownHopperSwipeTutorial().set(true)
+        }
+        controller.hopperGravity = controller.preferences.hopperGravity().get()
+        controller.category_hopper_frame.translationX = 0f
+    }
+
+    private companion object {
+        const val SWIPE_THRESHOLD = 50
+        const val SWIPE_VELOCITY_THRESHOLD = 100
+    }
 }

app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt

@@ -682,8 +682,8 @@ open class MainActivity : BaseActivity(), DownloadServiceListener {
 
     companion object {
 
-        const val SWIPE_THRESHOLD = 100
-        const val SWIPE_VELOCITY_THRESHOLD = 100
+        private const val SWIPE_THRESHOLD = 100
+        private const val SWIPE_VELOCITY_THRESHOLD = 100
 
         // Shortcut actions
         const val SHORTCUT_LIBRARY = "eu.kanade.tachiyomi.SHOW_LIBRARY"