Conversation tab bar animations.

app/src/main/java/org/thoughtcrime/securesms/stories/tabs/ConversationListTabsFragment.kt

@@ -1,10 +1,20 @@
 package org.thoughtcrime.securesms.stories.tabs
 
+import android.animation.Animator
+import android.animation.AnimatorSet
+import android.animation.ValueAnimator
 import android.os.Bundle
 import android.view.View
+import android.widget.ImageView
 import android.widget.TextView
+import androidx.core.content.ContextCompat
+import androidx.core.view.animation.PathInterpolatorCompat
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
+import com.airbnb.lottie.LottieAnimationView
+import com.airbnb.lottie.LottieProperty
+import com.airbnb.lottie.model.KeyPath
+import org.signal.core.util.DimensionUnit
 import org.thoughtcrime.securesms.R
 import org.thoughtcrime.securesms.util.visible
 import java.text.NumberFormat
@@ -18,14 +28,32 @@ class ConversationListTabsFragment : Fragment(R.layout.conversation_list_tabs) {
 
   private lateinit var chatsUnreadIndicator: TextView
   private lateinit var storiesUnreadIndicator: TextView
-  private lateinit var chatsIcon: View
-  private lateinit var storiesIcon: View
+  private lateinit var chatsIcon: LottieAnimationView
+  private lateinit var storiesIcon: LottieAnimationView
+  private lateinit var chatsPill: ImageView
+  private lateinit var storiesPill: ImageView
+
+  private var pillAnimator: Animator? = null
 
   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
     chatsUnreadIndicator = view.findViewById(R.id.chats_unread_indicator)
     storiesUnreadIndicator = view.findViewById(R.id.stories_unread_indicator)
     chatsIcon = view.findViewById(R.id.chats_tab_icon)
     storiesIcon = view.findViewById(R.id.stories_tab_icon)
+    chatsPill = view.findViewById(R.id.chats_pill)
+    storiesPill = view.findViewById(R.id.stories_pill)
+
+    val iconTint = ContextCompat.getColor(requireContext(), R.color.signal_colorOnSecondaryContainer)
+
+    chatsIcon.addValueCallback(
+      KeyPath("**"),
+      LottieProperty.COLOR
+    ) { iconTint }
+
+    storiesIcon.addValueCallback(
+      KeyPath("**"),
+      LottieProperty.COLOR
+    ) { iconTint }
 
     view.findViewById<View>(R.id.chats_tab_touch_point).setOnClickListener {
       viewModel.onChatsSelected()
@@ -39,9 +67,19 @@ class ConversationListTabsFragment : Fragment(R.layout.conversation_list_tabs) {
   }
 
   private fun update(state: ConversationListTabsState) {
+    val wasChatSelected = chatsIcon.isSelected
+
     chatsIcon.isSelected = state.tab == ConversationListTab.CHATS
     storiesIcon.isSelected = state.tab == ConversationListTab.STORIES
 
+    chatsPill.isSelected = chatsIcon.isSelected
+    storiesPill.isSelected = storiesIcon.isSelected
+
+    if (chatsIcon.isSelected xor wasChatSelected) {
+      runLottieAnimations(chatsIcon, storiesIcon)
+      runPillAnimation(chatsPill, storiesPill)
+    }
+
     chatsUnreadIndicator.visible = state.unreadChatsCount > 0
     chatsUnreadIndicator.text = formatCount(state.unreadChatsCount)
 
@@ -51,6 +89,47 @@ class ConversationListTabsFragment : Fragment(R.layout.conversation_list_tabs) {
     requireView().visible = !state.isSearchOpen
   }
 
+  private fun runLottieAnimations(vararg toAnimate: LottieAnimationView) {
+    toAnimate.forEach {
+      if (it.isSelected) {
+        it.resumeAnimation()
+      } else {
+        if (it.isAnimating) {
+          it.pauseAnimation()
+        }
+
+        it.progress = 0f
+      }
+    }
+  }
+
+  private fun runPillAnimation(vararg toAnimate: ImageView) {
+    val (selected, unselected) = toAnimate.partition { it.isSelected }
+
+    pillAnimator?.cancel()
+    pillAnimator = AnimatorSet().apply {
+      duration = 150
+      interpolator = PathInterpolatorCompat.create(0.17f, 0.17f, 0f, 1f)
+      playTogether(
+        selected.map { view ->
+          view.visibility = View.VISIBLE
+          ValueAnimator.ofInt(view.paddingLeft, 0).apply {
+            addUpdateListener {
+              view.setPadding(it.animatedValue as Int, 0, it.animatedValue as Int, 0)
+            }
+          }
+        }
+      )
+      start()
+    }
+
+    unselected.forEach {
+      val smallPad = DimensionUnit.DP.toPixels(16f).toInt()
+      it.setPadding(smallPad, 0, smallPad, 0)
+      it.visibility = View.INVISIBLE
+    }
+  }
+
   private fun formatCount(count: Long): String {
     if (count > 99L) {
       return getString(R.string.ConversationListTabs__99p)