[Catalog][Predictive Back][Side Sheet] Update side sheet state handling to be more accurate in demos

Fixes inaccurate state label text and back callback enabled flag after rotation

Resolves #3575

PiperOrigin-RevId: 566433974

Author: dsn5ft

catalog/java/io/material/catalog/sidesheet/SideSheetMainDemoFragment.java

@@ -186,31 +186,38 @@ private void setUpSheetGravityButtonToggleGroup(@NonNull View view) {
         });
   }
 
-  private void setupBackHandling(SideSheetBehavior<View> sideSheetBehavior) {
+  private void setupBackHandling(View sideSheet, SideSheetBehavior<View> sideSheetBehavior) {
     OnBackPressedCallback nonModalOnBackPressedCallback =
         createNonModalOnBackPressedCallback(sideSheetBehavior);
     requireActivity().getOnBackPressedDispatcher().addCallback(this, nonModalOnBackPressedCallback);
     sideSheetBehavior.addCallback(
         new SideSheetCallback() {
           @Override
           public void onStateChanged(@NonNull View sheet, int newState) {
-            switch (newState) {
-              case SideSheetBehavior.STATE_EXPANDED:
-              case SideSheetBehavior.STATE_SETTLING:
-                nonModalOnBackPressedCallback.setEnabled(true);
-                break;
-              case SideSheetBehavior.STATE_HIDDEN:
-                nonModalOnBackPressedCallback.setEnabled(false);
-                break;
-              case SideSheetBehavior.STATE_DRAGGING:
-              default:
-                break;
-            }
+            updateBackHandlingEnabled(nonModalOnBackPressedCallback, newState);
           }
 
           @Override
           public void onSlide(@NonNull View sheet, float slideOffset) {}
         });
+    sideSheet.post(
+        () ->
+            updateBackHandlingEnabled(nonModalOnBackPressedCallback, sideSheetBehavior.getState()));
+  }
+
+  private void updateBackHandlingEnabled(OnBackPressedCallback onBackPressedCallback, int state) {
+    switch (state) {
+      case SideSheetBehavior.STATE_EXPANDED:
+      case SideSheetBehavior.STATE_SETTLING:
+        onBackPressedCallback.setEnabled(true);
+        break;
+      case SideSheetBehavior.STATE_HIDDEN:
+        onBackPressedCallback.setEnabled(false);
+        break;
+      case SideSheetBehavior.STATE_DRAGGING:
+      default:
+        break;
+    }
   }
 
   private View setUpSideSheet(
@@ -227,7 +234,7 @@ private View setUpSideSheet(
     View standardSideSheetCloseIconButton = sideSheet.findViewById(closeIconButtonId);
     standardSideSheetCloseIconButton.setOnClickListener(v -> hideSideSheet(sideSheetBehavior));
 
-    setupBackHandling(sideSheetBehavior);
+    setupBackHandling(sideSheet, sideSheetBehavior);
 
     sideSheetViews.add(sideSheet);
 
@@ -237,9 +244,10 @@ private View setUpSideSheet(
   private void setSideSheetCallback(
       View sideSheet, @IdRes int stateTextViewId, @IdRes int slideOffsetTextId) {
     SideSheetBehavior<View> sideSheetBehavior = SideSheetBehavior.from(sideSheet);
+    TextView stateTextView = sideSheet.findViewById(stateTextViewId);
     sideSheetBehavior.addCallback(
-        createSideSheetCallback(
-            sideSheet.findViewById(stateTextViewId), sideSheet.findViewById(slideOffsetTextId)));
+        createSideSheetCallback(stateTextView, sideSheet.findViewById(slideOffsetTextId)));
+    sideSheet.post(() -> updateStateTextView(stateTextView, sideSheetBehavior.getState()));
   }
 
   private void setUpDetachedModalSheet() {
@@ -373,22 +381,7 @@ private SideSheetCallback createSideSheetCallback(
     return new SideSheetCallback() {
       @Override
       public void onStateChanged(@NonNull View sheet, int newState) {
-        stateTextView.setVisibility(View.VISIBLE);
-
-        switch (newState) {
-          case SideSheetBehavior.STATE_DRAGGING:
-            stateTextView.setText(R.string.cat_sidesheet_state_dragging);
-            break;
-          case SideSheetBehavior.STATE_EXPANDED:
-            stateTextView.setText(R.string.cat_sidesheet_state_expanded);
-            break;
-          case SideSheetBehavior.STATE_SETTLING:
-            stateTextView.setText(R.string.cat_sidesheet_state_settling);
-            break;
-          case SideSheetBehavior.STATE_HIDDEN:
-          default:
-            break;
-        }
+        updateStateTextView(stateTextView, newState);
       }
 
       @Override
@@ -400,6 +393,25 @@ public void onSlide(@NonNull View sheet, float slideOffset) {
     };
   }
 
+  private void updateStateTextView(@NonNull TextView stateTextView, int state) {
+    stateTextView.setVisibility(View.VISIBLE);
+
+    switch (state) {
+      case SideSheetBehavior.STATE_DRAGGING:
+        stateTextView.setText(R.string.cat_sidesheet_state_dragging);
+        break;
+      case SideSheetBehavior.STATE_EXPANDED:
+        stateTextView.setText(R.string.cat_sidesheet_state_expanded);
+        break;
+      case SideSheetBehavior.STATE_SETTLING:
+        stateTextView.setText(R.string.cat_sidesheet_state_settling);
+        break;
+      case SideSheetBehavior.STATE_HIDDEN:
+      default:
+        break;
+    }
+  }
+
   private OnBackPressedCallback createNonModalOnBackPressedCallback(
       SideSheetBehavior<View> behavior) {
     return new OnBackPressedCallback(/* enabled= */ false) {