From 245ffe72368be98d73909227732299b869a6a36a Mon Sep 17 00:00:00 2001
From: dniz <dniz@google.com>
Date: Wed, 30 Jun 2021 06:01:23 -0700
Subject: [PATCH] [CollapsingToolbarLayout] Added option to force always
 applying system window inset top regardless of layout_height

PiperOrigin-RevId: 382286923
---
 .../res/layout/cat_toc_fragment.xml           |  4 +--
 .../tableofcontents/res/values/dimens.xml     |  3 +-
 .../appbar/CollapsingToolbarLayout.java       | 32 ++++++++++++++++---
 .../material/appbar/res/values/attrs.xml      |  3 ++
 4 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/catalog/java/io/material/catalog/tableofcontents/res/layout/cat_toc_fragment.xml b/catalog/java/io/material/catalog/tableofcontents/res/layout/cat_toc_fragment.xml
index 36f0677b482..a91932d1317 100644
--- a/catalog/java/io/material/catalog/tableofcontents/res/layout/cat_toc_fragment.xml
+++ b/catalog/java/io/material/catalog/tableofcontents/res/layout/cat_toc_fragment.xml
@@ -27,14 +27,14 @@
   <com.google.android.material.appbar.AppBarLayout
       android:id="@+id/cat_toc_app_bar_layout"
       android:layout_width="match_parent"
-      android:layout_height="@dimen/cat_toc_tall_toolbar_height"
+      android:layout_height="wrap_content"
       android:theme="@style/ThemeOverlay.Catalog.AppBarLayout"
       android:fitsSystemWindows="true">
 
     <com.google.android.material.appbar.CollapsingToolbarLayout
         android:id="@+id/cat_toc_collapsingtoolbarlayout"
         android:layout_width="match_parent"
-        android:layout_height="match_parent"
+        android:layout_height="@dimen/cat_toc_tall_toolbar_height"
         app:layout_scrollFlags="scroll|exitUntilCollapsed|snap"
         app:titleEnabled="false">
 
diff --git a/catalog/java/io/material/catalog/tableofcontents/res/values/dimens.xml b/catalog/java/io/material/catalog/tableofcontents/res/values/dimens.xml
index ffc4f12be0d..33c5c7c075c 100644
--- a/catalog/java/io/material/catalog/tableofcontents/res/values/dimens.xml
+++ b/catalog/java/io/material/catalog/tableofcontents/res/values/dimens.xml
@@ -16,8 +16,7 @@
   -->
 
 <resources>
-  <dimen name="cat_toc_tall_toolbar_height">128dp</dimen>
-  <dimen name="cat_toc_short_toolbar_height">128dp</dimen>
+  <dimen name="cat_toc_tall_toolbar_height">112dp</dimen>
   <dimen name="cat_toc_toolbar_image_offset">16dp</dimen>
   <dimen name="cat_toc_grid_divider_size">1dp</dimen>
   <dimen name="cat_toc_item_size">180dp</dimen>
diff --git a/lib/java/com/google/android/material/appbar/CollapsingToolbarLayout.java b/lib/java/com/google/android/material/appbar/CollapsingToolbarLayout.java
index 58d529e312b..73473b82b11 100644
--- a/lib/java/com/google/android/material/appbar/CollapsingToolbarLayout.java
+++ b/lib/java/com/google/android/material/appbar/CollapsingToolbarLayout.java
@@ -173,6 +173,8 @@ public class CollapsingToolbarLayout extends FrameLayout {
   @TitleCollapseMode private int titleCollapseMode;
 
   @Nullable WindowInsetsCompat lastInsets;
+  private int topInsetApplied = 0;
+  private boolean forceApplySystemWindowInsetTop = false;
 
   public CollapsingToolbarLayout(@NonNull Context context) {
     this(context, null);
@@ -273,6 +275,9 @@ public CollapsingToolbarLayout(@NonNull Context context, @Nullable AttributeSet
 
     toolbarId = a.getResourceId(R.styleable.CollapsingToolbarLayout_toolbarId, -1);
 
+    forceApplySystemWindowInsetTop =
+        a.getBoolean(R.styleable.CollapsingToolbarLayout_forceApplySystemWindowInsetTop, false);
+
     a.recycle();
 
     setWillNotDraw(false);
@@ -516,9 +521,10 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 
     final int mode = MeasureSpec.getMode(heightMeasureSpec);
     final int topInset = lastInsets != null ? lastInsets.getSystemWindowInsetTop() : 0;
-    if (mode == MeasureSpec.UNSPECIFIED && topInset > 0) {
-      // If we have a top inset and we're set to wrap_content height we need to make sure
-      // we add the top inset to our height, therefore we re-measure
+    if ((mode == MeasureSpec.UNSPECIFIED || forceApplySystemWindowInsetTop) && topInset > 0) {
+      // If we have a top inset and we're set to wrap_content height or force apply,
+      // we need to make sure we add the top inset to our height, therefore we re-measure
+      topInsetApplied = topInset;
       heightMeasureSpec =
           MeasureSpec.makeMeasureSpec(getMeasuredHeight() + topInset, MeasureSpec.EXACTLY);
       super.onMeasure(widthMeasureSpec, heightMeasureSpec);
@@ -1310,6 +1316,24 @@ public boolean isRtlTextDirectionHeuristicsEnabled() {
     return collapsingTextHelper.isRtlTextDirectionHeuristicsEnabled();
   }
 
+  /**
+   * Sets whether the top system window inset should be respected regardless of what the
+   * {@code layout_height} of the {@code CollapsingToolbarLayout} is set to. Experimental Feature.
+   */
+  @RestrictTo(LIBRARY_GROUP)
+  public void setForceApplySystemWindowInsetTop(boolean forceApplySystemWindowInsetTop) {
+    this.forceApplySystemWindowInsetTop = forceApplySystemWindowInsetTop;
+  }
+
+  /**
+   * Gets whether the top system window inset should be respected regardless of what the
+   * {@code layout_height} of the {@code CollapsingToolbarLayout} is set to. Experimental Feature.
+   */
+  @RestrictTo(LIBRARY_GROUP)
+  public boolean isForceApplySystemWindowInsetTop() {
+    return forceApplySystemWindowInsetTop;
+  }
+
   /**
    * Set the amount of visible height in pixels used to define when to trigger a scrim visibility
    * change.
@@ -1338,7 +1362,7 @@ public void setScrimVisibleHeightTrigger(@IntRange(from = 0) final int height) {
   public int getScrimVisibleHeightTrigger() {
     if (scrimVisibleHeightTrigger >= 0) {
       // If we have one explicitly set, return it
-      return scrimVisibleHeightTrigger;
+      return scrimVisibleHeightTrigger + topInsetApplied;
     }
 
     // Otherwise we'll use the default computed value
diff --git a/lib/java/com/google/android/material/appbar/res/values/attrs.xml b/lib/java/com/google/android/material/appbar/res/values/attrs.xml
index b55b11d770f..b74698cec83 100644
--- a/lib/java/com/google/android/material/appbar/res/values/attrs.xml
+++ b/lib/java/com/google/android/material/appbar/res/values/attrs.xml
@@ -206,6 +206,9 @@
     </attr>
     <!-- The maximum number of lines to display in the expanded state. Experimental Feature. -->
     <attr name="maxLines" format="integer" />
+    <!-- Whether the system window inset top should be applied regardless of
+         what the layout_height is set to. Experimental Feature. -->
+    <attr name="forceApplySystemWindowInsetTop" format="boolean" />
   </declare-styleable>
 
   <declare-styleable name="CollapsingToolbarLayout_Layout">