[Bottom Sheet] Updated peek height gesture inset behavior to only add extra inset if necessary

Previously on Q the peek height would have the bottom gesture inset size added to it regardless of whether edge to edge mode or gesture navigation were enabled. Now the extra inset will only be added if it is needed due to a system gesture conflict, in order to give the user some space to drag the sheet.

Resolves #1472

PiperOrigin-RevId: 320606747
(cherry picked from commit 7b62003)

Author: dsn5ft

lib/java/com/google/android/material/bottomsheet/BottomSheetBehavior.java

@@ -16,8 +16,6 @@
 
 package com.google.android.material.bottomsheet;
 
-import com.google.android.material.R;
-
 import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
 
 import android.animation.ValueAnimator;
@@ -30,31 +28,34 @@
 import android.os.Build.VERSION_CODES;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.util.TypedValue;
+import android.view.MotionEvent;
+import android.view.VelocityTracker;
+import android.view.View;
+import android.view.ViewConfiguration;
+import android.view.ViewGroup;
+import android.view.ViewParent;
 import androidx.annotation.FloatRange;
 import androidx.annotation.IntDef;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RestrictTo;
 import androidx.annotation.VisibleForTesting;
+import androidx.coordinatorlayout.widget.CoordinatorLayout;
+import androidx.coordinatorlayout.widget.CoordinatorLayout.LayoutParams;
 import androidx.core.math.MathUtils;
-import androidx.customview.view.AbsSavedState;
 import androidx.core.view.ViewCompat;
+import androidx.core.view.WindowInsetsCompat;
 import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;
 import androidx.core.view.accessibility.AccessibilityNodeInfoCompat.AccessibilityActionCompat;
 import androidx.core.view.accessibility.AccessibilityViewCommand;
+import androidx.customview.view.AbsSavedState;
 import androidx.customview.widget.ViewDragHelper;
-import android.util.AttributeSet;
-import android.util.Log;
-import android.util.TypedValue;
-import android.view.MotionEvent;
-import android.view.VelocityTracker;
-import android.view.View;
-import android.view.ViewConfiguration;
-import android.view.ViewGroup;
-import android.view.ViewParent;
-import android.view.WindowInsets;
-import androidx.coordinatorlayout.widget.CoordinatorLayout;
-import androidx.coordinatorlayout.widget.CoordinatorLayout.LayoutParams;
+import com.google.android.material.R;
+import com.google.android.material.internal.ViewUtils;
+import com.google.android.material.internal.ViewUtils.RelativePadding;
 import com.google.android.material.resources.MaterialResources;
 import com.google.android.material.shape.MaterialShapeDrawable;
 import com.google.android.material.shape.ShapeAppearanceModel;
@@ -370,7 +371,7 @@ public boolean onLayoutChild(
       // First layout with this behavior.
       peekHeightMin =
           parent.getResources().getDimensionPixelSize(R.dimen.design_bottom_sheet_peek_height_min);
-      setSystemGestureInsets(parent);
+      setSystemGestureInsets(child);
       viewRef = new WeakReference<>(child);
       // Only set MaterialShapeDrawable as background if shapeTheming is enabled, otherwise will
       // default to android:background declared in styles or layout.
@@ -1237,13 +1238,22 @@ public void onAnimationUpdate(@NonNull ValueAnimator animation) {
         });
   }
 
-  private void setSystemGestureInsets(@NonNull CoordinatorLayout parent) {
-    if (VERSION.SDK_INT >= VERSION_CODES.Q && !isGestureInsetBottomIgnored()) {
-      WindowInsets windowInsets = parent.getRootWindowInsets();
-      if (windowInsets != null) {
-        int systemMandatoryInsetsBottom = windowInsets.getSystemGestureInsets().bottom;
-        peekHeight += systemMandatoryInsetsBottom;
-      }
+  /**
+   * Ensure the peek height is at least as large as the bottom gesture inset size so that the sheet
+   * can always be dragged, but only when the inset is required by the system.
+   */
+  private void setSystemGestureInsets(@NonNull View child) {
+    if (VERSION.SDK_INT >= VERSION_CODES.Q && !isGestureInsetBottomIgnored() && !peekHeightAuto) {
+      ViewUtils.doOnApplyWindowInsets(
+          child,
+          new ViewUtils.OnApplyWindowInsetsListener() {
+            @Override
+            public WindowInsetsCompat onApplyWindowInsets(
+                View view, WindowInsetsCompat insets, RelativePadding initialPadding) {
+              setPeekHeight(peekHeight + insets.getMandatorySystemGestureInsets().bottom);
+              return insets;
+            }
+          });
     }
   }