Move multiselect animation code to decorator.

app/src/main/java/org/thoughtcrime/securesms/conversation/BodyBubbleLayoutTransition.kt

@@ -23,7 +23,7 @@ class BodyBubbleLayoutTransition(bodyBubble: ConversationItemBodyBubble) : Layou
       val parentRecycler: RecyclerView? = bodyBubble.parent.parent as? RecyclerView
 
       try {
-        parentRecycler?.invalidateItemDecorations()
+        parentRecycler?.invalidate()
       } catch (e: IllegalStateException) {
         // In scroll or layout. Skip this frame.
       }

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationFragment.java

@@ -266,18 +266,9 @@ public class ConversationFragment extends LoggingFragment implements Multiselect
       } else {
         return Util.hasItems(adapter.getSelectedItems());
       }
-    }, () -> listSubmissionCount < 2, multiselectPart -> {
-      ConversationAdapter adapter = getListAdapter();
-      if (adapter == null) {
-        return false;
-      } else {
-        return adapter.getSelectedItems().contains(multiselectPart);
-      }
-    }, () -> list.canScrollVertically(1) || list.canScrollVertically(-1));
+    }, () -> listSubmissionCount < 2, () -> list.canScrollVertically(1) || list.canScrollVertically(-1));
     multiselectItemDecoration = new MultiselectItemDecoration(requireContext(),
-                                                              () -> conversationViewModel.getWallpaper().getValue(),
-                                                              multiselectItemAnimator::getSelectedProgressForPart,
-                                                              multiselectItemAnimator::isInitialMultiSelectAnimation);
+                                                              () -> conversationViewModel.getWallpaper().getValue());
 
     list.setHasFixedSize(false);
     list.setLayoutManager(layoutManager);

app/src/main/java/org/thoughtcrime/securesms/conversation/mutiselect/MultiselectItemAnimator.kt

@@ -14,15 +14,9 @@ import androidx.recyclerview.widget.RecyclerView
 class MultiselectItemAnimator(
   private val isInMultiSelectMode: () -> Boolean,
   private val isLoadingInitialContent: () -> Boolean,
-  private val isPartSelected: (MultiselectPart) -> Boolean,
   private val isParentFilled: () -> Boolean
 ) : RecyclerView.ItemAnimator() {
 
-  private data class Selection(
-    val multiselectPart: MultiselectPart,
-    val viewHolder: RecyclerView.ViewHolder
-  )
-
   private data class SlideInfo(
     val viewHolder: RecyclerView.ViewHolder,
     val operation: Operation
@@ -33,25 +27,10 @@ class MultiselectItemAnimator(
     CHANGE
   }
 
-  var isInitialMultiSelectAnimation: Boolean = true
-    private set
-
-  private val selected: MutableSet<MultiselectPart> = mutableSetOf()
-
-  private val pendingSelectedAnimations: MutableSet<Selection> = mutableSetOf()
   private val pendingSlideAnimations: MutableSet<SlideInfo> = mutableSetOf()
 
-  private val selectedAnimations: MutableMap<Selection, ValueAnimator> = mutableMapOf()
   private val slideAnimations: MutableMap<SlideInfo, ValueAnimator> = mutableMapOf()
 
-  fun getSelectedProgressForPart(multiselectPart: MultiselectPart): Float {
-    return if (pendingSelectedAnimations.any { it.multiselectPart == multiselectPart }) {
-      0f
-    } else {
-      selectedAnimations.filter { it.key.multiselectPart == multiselectPart }.values.firstOrNull()?.animatedFraction ?: 1f
-    }
-  }
-
   override fun animateDisappearance(viewHolder: RecyclerView.ViewHolder, preLayoutInfo: ItemHolderInfo, postLayoutInfo: ItemHolderInfo?): Boolean {
     dispatchAnimationFinished(viewHolder)
     return false
@@ -102,52 +81,20 @@ class MultiselectItemAnimator(
     }
 
     val isInMultiSelectMode = isInMultiSelectMode()
-    if (!isInMultiSelectMode) {
-      selected.clear()
-      isInitialMultiSelectAnimation = true
-      return if (preLayoutInfo.top == postLayoutInfo.top) {
+    return if (!isInMultiSelectMode) {
+      if (preLayoutInfo.top == postLayoutInfo.top) {
         dispatchAnimationFinished(newHolder)
         false
       } else {
         animateSlide(newHolder, preLayoutInfo, postLayoutInfo, Operation.CHANGE)
       }
-    }
-
-    var isAnimationStarted = false
-    val parts: MultiselectCollection? = (newHolder.itemView as? Multiselectable)?.conversationMessage?.multiselectCollection
-
-    if (parts == null || parts.isExpired()) {
-      dispatchAnimationFinished(newHolder)
-      return false
-    }
-
-    parts.toSet().forEach { part ->
-      val partIsSelected = isPartSelected(part)
-      if (selected.contains(part) && !partIsSelected) {
-        pendingSelectedAnimations.add(Selection(part, newHolder))
-        selected.remove(part)
-        isAnimationStarted = true
-      } else if (!selected.contains(part) && partIsSelected) {
-        pendingSelectedAnimations.add(Selection(part, newHolder))
-        selected.add(part)
-        isAnimationStarted = true
-      } else if (isInitialMultiSelectAnimation) {
-        pendingSelectedAnimations.add(Selection(part, newHolder))
-        isAnimationStarted = true
-      }
-    }
-
-    if (isAnimationStarted) {
-      dispatchAnimationStarted(newHolder)
     } else {
       dispatchAnimationFinished(newHolder)
+      false
     }
-
-    return isAnimationStarted
   }
 
   override fun runPendingAnimations() {
-    runPendingSelectedAnimations()
     runPendingSlideAnimations()
   }
 
@@ -157,7 +104,7 @@ class MultiselectItemAnimator(
       slideAnimations[slideInfo] = animator
       animator.duration = 150L
       animator.addUpdateListener {
-        (slideInfo.viewHolder.itemView.parent as RecyclerView?)?.invalidateItemDecorations()
+        (slideInfo.viewHolder.itemView.parent as RecyclerView?)?.invalidate()
       }
       animator.doOnEnd {
         dispatchAnimationFinished(slideInfo.viewHolder)
@@ -169,51 +116,22 @@ class MultiselectItemAnimator(
     pendingSlideAnimations.clear()
   }
 
-  private fun runPendingSelectedAnimations() {
-    for (selection in pendingSelectedAnimations) {
-      val animator = ValueAnimator.ofFloat(0f, 1f)
-      selectedAnimations[selection] = animator
-      animator.duration = 150L
-      animator.addUpdateListener {
-        (selection.viewHolder.itemView.parent as RecyclerView?)?.invalidateItemDecorations()
-      }
-      animator.doOnEnd {
-        dispatchAnimationFinished(selection.viewHolder)
-        selectedAnimations.remove(selection)
-        isInitialMultiSelectAnimation = false
-      }
-      animator.start()
-    }
-
-    pendingSelectedAnimations.clear()
-  }
-
   override fun endAnimation(item: RecyclerView.ViewHolder) {
-    endSelectedAnimation(item)
     endSlideAnimation(item)
   }
 
   override fun endAnimations() {
-    endSelectedAnimations()
     endSlideAnimations()
     dispatchAnimationsFinished()
   }
 
   override fun isRunning(): Boolean {
-    return (selectedAnimations.values + slideAnimations.values).any { it.isRunning }
+    return slideAnimations.values.any { it.isRunning }
   }
 
   override fun onAnimationFinished(viewHolder: RecyclerView.ViewHolder) {
     val parent = (viewHolder.itemView.parent as? RecyclerView)
-    parent?.post { parent.invalidateItemDecorations() }
-  }
-
-  private fun endSelectedAnimation(item: RecyclerView.ViewHolder) {
-    val selections = selectedAnimations.filter { (k, _) -> k.viewHolder == item }
-    selections.forEach { (k, v) ->
-      v.end()
-      selectedAnimations.remove(k)
-    }
+    parent?.post { parent.invalidate() }
   }
 
   private fun endSlideAnimation(item: RecyclerView.ViewHolder) {
@@ -224,11 +142,6 @@ class MultiselectItemAnimator(
     }
   }
 
-  fun endSelectedAnimations() {
-    selectedAnimations.values.forEach { it.end() }
-    selectedAnimations.clear()
-  }
-
   fun endSlideAnimations() {
     slideAnimations.values.forEach { it.end() }
     slideAnimations.clear()

app/src/main/java/org/thoughtcrime/securesms/conversation/mutiselect/MultiselectItemDecoration.kt

@@ -1,5 +1,6 @@
 package org.thoughtcrime.securesms.conversation.mutiselect
 
+import android.animation.ValueAnimator
 import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.Canvas
@@ -32,9 +33,7 @@ import java.lang.Integer.max
  */
 class MultiselectItemDecoration(
   context: Context,
-  private val chatWallpaperProvider: () -> ChatWallpaper?,
-  private val selectedAnimationProgressProvider: (MultiselectPart) -> Float,
-  private val isInitialAnimation: () -> Boolean
+  private val chatWallpaperProvider: () -> ChatWallpaper?
 ) : RecyclerView.ItemDecoration(), DefaultLifecycleObserver {
 
   private val path = Path()
@@ -54,6 +53,10 @@ class MultiselectItemDecoration(
   private val ultramarine30 = ContextCompat.getColor(context, R.color.core_ultramarine_33)
   private val ultramarine = ContextCompat.getColor(context, R.color.signal_accent_primary)
 
+  private val selectedParts: MutableSet<MultiselectPart> = mutableSetOf()
+  private var enterExitAnimation: ValueAnimator? = null
+  private val multiselectPartAnimatorMap: MutableMap<MultiselectPart, ValueAnimator> = mutableMapOf()
+
   private var checkedBitmap: Bitmap? = null
 
   private var focusedItem: MultiselectPart? = null
@@ -99,7 +102,34 @@ class MultiselectItemDecoration(
     style = Paint.Style.FILL
   }
 
+  private fun getCurrentSelection(parent: RecyclerView): Set<MultiselectPart> {
+    return (parent.adapter as ConversationAdapter).selectedItems
+  }
+
   override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
+    val currentSelection = getCurrentSelection(parent)
+    if (selectedParts.isEmpty() && currentSelection.isNotEmpty()) {
+      enterExitAnimation?.end()
+      enterExitAnimation = ValueAnimator.ofFloat(enterExitAnimation?.animatedFraction ?: 0f, 1f).apply {
+        duration = 150L
+        start()
+      }
+    } else if (selectedParts.isNotEmpty() && currentSelection.isEmpty()) {
+      enterExitAnimation?.end()
+      enterExitAnimation = ValueAnimator.ofFloat(enterExitAnimation?.animatedFraction ?: 1f, 0f).apply {
+        duration = 150L
+        start()
+      }
+    }
+
+    if (view is Multiselectable) {
+      val parts = view.conversationMessage.multiselectCollection.toSet()
+      parts.forEach { updateMultiselectPartAnimator(currentSelection, it) }
+    }
+
+    selectedParts.clear()
+    selectedParts.addAll(currentSelection)
+
     outRect.setEmpty()
     updateChildOffsets(parent, view)
   }
@@ -151,6 +181,8 @@ class MultiselectItemDecoration(
 
       canvas.restore()
     }
+
+    drawChecks(parent, canvas, adapter)
   }
 
   /**
@@ -160,9 +192,12 @@ class MultiselectItemDecoration(
     val adapter = parent.adapter as ConversationAdapter
     if (adapter.selectedItems.isEmpty()) {
       drawFocusShadeOverIfNecessary(canvas, parent)
-      return
     }
 
+    invalidateIfAnimatorsAreRunning(parent)
+  }
+
+  private fun drawChecks(parent: RecyclerView, canvas: Canvas, adapter: ConversationAdapter) {
     val drawCircleBehindSelector = chatWallpaperProvider()?.isPhoto == true
     val multiselectChildren: Sequence<Multiselectable> = parent.children.filterIsInstance(Multiselectable::class.java)
 
@@ -190,7 +225,7 @@ class MultiselectItemDecoration(
           drawPhotoCircle(canvas, parent, topBoundary, bottomBoundary)
         }
 
-        val alphaProgress = selectedAnimationProgressProvider(it)
+        val alphaProgress = selectedAnimationProgress(it)
         if (adapter.selectedItems.contains(it)) {
           drawUnselectedCircle(canvas, parent, topBoundary, bottomBoundary, 1f - alphaProgress)
           drawSelectedCircle(canvas, parent, topBoundary, bottomBoundary, alphaProgress)
@@ -271,7 +306,6 @@ class MultiselectItemDecoration(
     val isLtr = ViewUtil.isLtr(child)
 
     if (adapter.selectedItems.isNotEmpty() && child is Multiselectable) {
-      val firstPart = child.conversationMessage.multiselectCollection.toSet().first()
       val target = child.getHorizontalTranslationTarget()
 
       if (target != null) {
@@ -282,7 +316,7 @@ class MultiselectItemDecoration(
         }
 
         val translation: Float = if (isInitialAnimation()) {
-          max(0, gutter - start) * selectedAnimationProgressProvider(firstPart)
+          max(0, gutter - start) * (enterExitAnimation?.animatedFraction ?: 1f)
         } else {
           max(0, gutter - start).toFloat()
         }
@@ -341,4 +375,62 @@ class MultiselectItemDecoration(
       canvas.restore()
     }
   }
+
+  private fun isInitialAnimation(): Boolean {
+    return (enterExitAnimation?.animatedFraction ?: 0f) < 1f
+  }
+
+  // This is reentrant
+  private fun updateMultiselectPartAnimator(currentSelection: Set<MultiselectPart>, multiselectPart: MultiselectPart) {
+    val difference: Difference = getDifferenceForPart(currentSelection, multiselectPart)
+    val animator: ValueAnimator? = multiselectPartAnimatorMap[multiselectPart]
+
+    when (difference) {
+      Difference.SAME -> Unit
+      Difference.ADDED -> {
+        val newAnimator = ValueAnimator.ofFloat(animator?.animatedFraction ?: 0f, 1f).apply {
+          duration = 150L
+          start()
+        }
+        animator?.end()
+        multiselectPartAnimatorMap[multiselectPart] = newAnimator
+      }
+      Difference.REMOVED -> {
+        val newAnimator = ValueAnimator.ofFloat(animator?.animatedFraction ?: 1f, 0f).apply {
+          duration = 150L
+          start()
+        }
+        animator?.end()
+        multiselectPartAnimatorMap[multiselectPart] = newAnimator
+      }
+    }
+  }
+
+  private fun selectedAnimationProgress(multiselectPart: MultiselectPart): Float {
+    val animator = multiselectPartAnimatorMap[multiselectPart]
+    return animator?.animatedFraction ?: 1f
+  }
+
+  private fun getDifferenceForPart(currentSelection: Set<MultiselectPart>, multiselectPart: MultiselectPart): Difference {
+    val isSelected = currentSelection.contains(multiselectPart)
+    val wasSelected = selectedParts.contains(multiselectPart)
+
+    return when {
+      isSelected && !wasSelected -> Difference.ADDED
+      !isSelected && wasSelected -> Difference.REMOVED
+      else -> Difference.SAME
+    }
+  }
+
+  private fun invalidateIfAnimatorsAreRunning(parent: RecyclerView) {
+    if (enterExitAnimation?.isRunning == true || multiselectPartAnimatorMap.values.any { it.isRunning }) {
+      parent.invalidate()
+    }
+  }
+
+  private enum class Difference {
+    REMOVED,
+    ADDED,
+    SAME
+  }
 }