Don't reserve space for typing view until somebody is typing

Once we show it, keep it, to not make the timeline jump around too much.

Change-Id: I8f863d8d21f3b06ff86f62615d8e6aefe81bde2e

vector/src/main/java/im/vector/app/features/home/room/detail/TimelineFragment.kt

@@ -50,6 +50,7 @@ import androidx.core.text.toSpannable
 import androidx.core.util.Pair
 import androidx.core.view.ViewCompat
 import androidx.core.view.forEach
+import androidx.core.view.isGone
 import androidx.core.view.isInvisible
 import androidx.core.view.isVisible
 import androidx.fragment.app.setFragmentResultListener
@@ -1692,14 +1693,24 @@ class TimelineFragment @Inject constructor(
         voiceMessageRecorderView.isVisible = false
     }
 
+    // Fully hide the typing message view with isGone, until the first user actually types
+    inline var View.isInvisibleOrGone: Boolean
+        get() = visibility != View.VISIBLE
+        set(value) {
+            // Set to invisible, unless it is already gone.
+            if (!value || !isGone) {
+                visibility = if (value) View.INVISIBLE else View.VISIBLE
+            }
+        }
+
     private fun renderTypingMessageNotification(roomSummary: RoomSummary?, state: RoomDetailViewState) {
         if (!isThreadTimeLine() && roomSummary != null) {
-            views.typingMessageView.isInvisible = state.typingUsers.isNullOrEmpty()
+            views.typingMessageView.isInvisibleOrGone = state.typingUsers.isNullOrEmpty()
             state.typingUsers
                     ?.take(MAX_TYPING_MESSAGE_USERS_COUNT)
                     ?.let { senders -> views.typingMessageView.render(senders, avatarRenderer) }
         } else {
-            views.typingMessageView.isInvisible = true
+            views.typingMessageView.isInvisibleOrGone = true
         }
     }
 

vector/src/main/res/layout/fragment_timeline.xml

@@ -97,6 +97,7 @@
         android:layout_width="0dp"
         android:paddingStart="20dp"
         android:paddingEnd="20dp"
+        android:visibility="gone"
         tools:visibility="visible"
         android:layout_height="20dp"/>