[TopAppBar] Fixed compress effect when toolbar is set as a support action bar and hiddin/shown.

getSupportActionBar.show/hide uses visibility to show/hide the toolbar which conflicted with the compress effect's use of Visibility to remove the toolbar when completely masked. This updates the compress effect to use alpha instead of visibility.

PiperOrigin-RevId: 619253990

Author: hunterstich

catalog/java/io/material/catalog/topappbar/TopAppBarCompressEffectFragment.java

@@ -68,6 +68,15 @@ public View onCreateDemoView(
     showHideTabsButton.setOnCheckedChangeListener(
         (buttonView, isChecked) -> updateTabVisibility(tabs, isChecked));
 
+    ToggleButton showHideToolbarButton = view.findViewById(R.id.show_hide_toolbar_button);
+    showHideToolbarButton.setOnCheckedChangeListener((buttonView, isChecked) -> {
+      if (isChecked) {
+        activity.getSupportActionBar().show();
+      } else {
+        activity.getSupportActionBar().hide();
+      }
+    });
+
     return view;
   }
 

catalog/java/io/material/catalog/topappbar/res/layout/cat_topappbar_compress_effect_fragment.xml

@@ -108,6 +108,16 @@
           android:textOn="@string/cat_topappbar_compress_hide_tabs_toggle_label"
           android:textOff="@string/cat_topappbar_compress_show_tabs_toggle_label" />
 
+      <ToggleButton
+        android:id="@+id/show_hide_toolbar_button"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center_horizontal"
+        android:layout_margin="8dp"
+        android:checked="true"
+        android:textOn="@string/cat_topappbar_compress_hide_toolbar_toggle_label"
+        android:textOff="@string/cat_topappbar_compress_show_toolbar_toggle_label" />
+
       <TextView
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"

catalog/java/io/material/catalog/topappbar/res/values/strings.xml

@@ -106,6 +106,8 @@
   <string name="cat_topappbar_compress_toolbar_title">Compress Title</string>
   <string name="cat_topappbar_compress_show_tabs_toggle_label">Show tabs</string>
   <string name="cat_topappbar_compress_hide_tabs_toggle_label">Hide tabs</string>
+  <string name="cat_topappbar_compress_show_toolbar_toggle_label">Show toolbar</string>
+  <string name="cat_topappbar_compress_hide_toolbar_toggle_label">Hide toolbar</string>
 
   <string name="cat_topappbar_tabs_label_all">All</string>
   <string name="cat_topappbar_tabs_label_shopping">Shopping</string>

lib/java/com/google/android/material/appbar/AppBarLayout.java

@@ -2579,16 +2579,16 @@ public void onOffsetChanged(
         // invisible. Otherwise, on API <= 24 a ghost rect that is outside of the drawing rect will
         // be ignored and the child would be drawn with no clipping.
         if (offsetY >= ghostRect.height()) {
-          child.setVisibility(INVISIBLE);
+          child.setAlpha(0f);
         } else {
-          child.setVisibility(VISIBLE);
+          child.setAlpha(1f);
         }
         ViewCompat.setClipBounds(child, ghostRect);
       } else {
         // Reset both the clip bounds and translationY of this view
         ViewCompat.setClipBounds(child, null);
         child.setTranslationY(0);
-        child.setVisibility(VISIBLE);
+        child.setAlpha(1f);
       }
     }
   }