Provide a public API for View#computeFitSystemWindows

The current hidden API is necessary to perform correct inset behavior
for support libraries like appcompat. Provide a public method
consistent with the new WindowInsets APIs.

Bug 17411097

Change-Id: I71a63eea0238b94cae6b5c6f1721d5567560ba81

3 files changed, 39 insertions, 0 deletions

diff --git a/api/current.txt b/api/current.txt
index e9da3987f4f9..db80bc44411e 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -33653,6 +33653,7 @@ package android.view {
     method protected int computeHorizontalScrollOffset();
     method protected int computeHorizontalScrollRange();
     method public void computeScroll();
+    method public android.view.WindowInsets computeSystemWindowInsets(android.view.WindowInsets, android.graphics.Rect);
     method protected int computeVerticalScrollExtent();
     method protected int computeVerticalScrollOffset();
     method protected int computeVerticalScrollRange();
@@ -34978,6 +34979,7 @@ package android.view {
     method public boolean isConsumed();
     method public boolean isRound();
     method public android.view.WindowInsets replaceSystemWindowInsets(int, int, int, int);
+    method public android.view.WindowInsets replaceSystemWindowInsets(android.graphics.Rect);
   }
 
   public abstract interface WindowManager implements android.view.ViewManager {
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index eb8f3bf1c064..ac006672b74a 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -6525,6 +6525,28 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
     }
 
     /**
+     * Compute insets that should be consumed by this view and the ones that should propagate
+     * to those under it.
+     *
+     * @param in Insets currently being processed by this View, likely received as a parameter
+     *           to {@link #onApplyWindowInsets(WindowInsets)}.
+     * @param outLocalInsets A Rect that will receive the insets that should be consumed
+     *                       by this view
+     * @return Insets that should be passed along to views under this one
+     */
+    public WindowInsets computeSystemWindowInsets(WindowInsets in, Rect outLocalInsets) {
+        if ((mViewFlags & OPTIONAL_FITS_SYSTEM_WINDOWS) == 0
+                || mAttachInfo == null
+                || (mAttachInfo.mSystemUiVisibility & SYSTEM_UI_LAYOUT_FLAGS) == 0) {
+            outLocalInsets.set(in.getSystemWindowInsets());
+            return in.consumeSystemWindowInsets();
+        } else {
+            outLocalInsets.set(0, 0, 0, 0);
+            return in;
+        }
+    }
+
+    /**
      * Sets whether or not this view should account for system screen decorations
      * such as the status bar and inset its content; that is, controlling whether
      * the default implementation of {@link #fitSystemWindows(Rect)} will be
diff --git a/core/java/android/view/WindowInsets.java b/core/java/android/view/WindowInsets.java
index 24c3c1a72ab0..2bfe3b42477d 100644
--- a/core/java/android/view/WindowInsets.java
+++ b/core/java/android/view/WindowInsets.java
@@ -341,6 +341,21 @@ public final class WindowInsets {
     }
 
     /**
+     * Returns a copy of this WindowInsets with selected system window insets replaced
+     * with new values.
+     *
+     * @param systemWindowInsets New system window insets. Each field is the inset in pixels
+     *                           for that edge
+     * @return A modified copy of this WindowInsets
+     */
+    public WindowInsets replaceSystemWindowInsets(Rect systemWindowInsets) {
+        final WindowInsets result = new WindowInsets(this);
+        result.mSystemWindowInsets = new Rect(systemWindowInsets);
+        result.mSystemWindowInsetsConsumed = !hasSystemWindowInsets();
+        return result;
+    }
+
+    /**
      * @hide
      */
     public WindowInsets consumeWindowDecorInsets() {