Fix spoiler animation running after view is returned to cache.

app/src/main/java/org/thoughtcrime/securesms/components/spoiler/SpoilerRendererDelegate.kt

@@ -5,6 +5,8 @@ import android.graphics.Canvas
 import android.text.Annotation
 import android.text.Layout
 import android.text.Spanned
+import android.view.View
+import android.view.View.OnAttachStateChangeListener
 import android.view.animation.LinearInterpolator
 import android.widget.TextView
 import org.thoughtcrime.securesms.components.spoiler.SpoilerAnnotation.SpoilerClickableSpan
@@ -42,6 +44,11 @@ class SpoilerRendererDelegate @JvmOverloads constructor(private val view: TextVi
     spoilerDrawable = SpoilerDrawable(textColor)
     single = SingleLineSpoilerRenderer(spoilerDrawable)
     multi = MultiLineSpoilerRenderer(spoilerDrawable)
+
+    view.addOnAttachStateChangeListener(object : OnAttachStateChangeListener {
+      override fun onViewDetachedFromWindow(v: View) = stopAnimating()
+      override fun onViewAttachedToWindow(v: View) = Unit
+    })
   }
 
   fun updateFromTextColor() {
@@ -90,11 +97,15 @@ class SpoilerRendererDelegate @JvmOverloads constructor(private val view: TextVi
         animatorRunning = true
       }
     } else {
-      animator.pause()
-      animatorRunning = false
+      stopAnimating()
     }
   }
 
+  private fun stopAnimating() {
+    animator.pause()
+    animatorRunning = false
+  }
+
   private inline fun <V> MutableMap<Int, V>.getFromCache(vararg keys: Any, default: () -> V): V {
     if (renderForComposing) {
       return default()