For mozilla-mobile#9044 - Improved DynamicDownloadDialog behaviour wh…

…en scrolling

app/src/main/java/org/mozilla/fenix/downloads/DynamicDownloadDialogBehavior.kt

@@ -34,6 +34,8 @@ class DynamicDownloadDialogBehavior<V : View>(
     private val bottomToolbarHeight: Float = 0f
 ) : CoordinatorLayout.Behavior<V>(context, attrs) {
 
+    private var expanded: Boolean = true
+
     @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
     internal var shouldSnapAfterScroll: Boolean = false
 
@@ -93,13 +95,14 @@ class DynamicDownloadDialogBehavior<V : View>(
         type: Int
     ) {
         if (shouldSnapAfterScroll || type == ViewCompat.TYPE_NON_TOUCH) {
-            val minHeight: Float =
-                if (bottomToolbarHeight > 0) bottomToolbarHeight else child.height.toFloat()
-
-            if (child.translationY >= minHeight / 2) {
-                animateSnap(child, SnapDirection.DOWN)
+            if (expanded) {
+                if (child.translationY >= bottomToolbarHeight / 2)
+                    animateSnap(child, SnapDirection.DOWN)
+                else animateSnap(child, SnapDirection.UP)
             } else {
-                animateSnap(child, SnapDirection.UP)
+                if (child.translationY < (bottomToolbarHeight + child.height.toFloat() / 2))
+                    animateSnap(child, SnapDirection.UP)
+                else animateSnap(child, SnapDirection.DOWN)
             }
         }
     }
@@ -140,6 +143,7 @@ class DynamicDownloadDialogBehavior<V : View>(
 
     @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
     internal fun animateSnap(child: View, direction: SnapDirection) = with(snapAnimator) {
+        expanded = direction == SnapDirection.UP
         addUpdateListener { child.translationY = it.animatedValue as Float }
         setFloatValues(
             child.translationY,