Split animation methods out of OnBackInvokedCallback

This makes OnBackInvokedCallback SAM compatible

Bug: 227789359
Test: atest \
        CtsWindowManagerDeviceTestCases:android.server.wm.BackNavigationLegacyTest \
        CtsWindowManagerDeviceTestCases:android.server.wm.BackNavigationTests \
        WmTests:com.android.server.wm.BackNavigationControllerTests \
        FrameworksCoreTests:android.window.BackNavigationTest \
        FrameworksCoreTests:android.window.WindowOnBackInvokedDispatcherTest \
        CtsViewTestCases:android.view.cts.OnBackInvokedDispatcherTest
Change-Id: Iab86b0488f1b3048eb02042191acaeb6a645a0bc

8 files changed, 93 insertions, 74 deletions

diff --git a/core/java/android/app/Activity.java b/core/java/android/app/Activity.java
index dff3c076727d..5537b075d42f 100644
--- a/core/java/android/app/Activity.java
+++ b/core/java/android/app/Activity.java
@@ -1663,12 +1663,7 @@ public class Activity extends ContextThemeWrapper
                 .isOnBackInvokedCallbackEnabled(this);
         if (aheadOfTimeBack) {
             // Add onBackPressed as default back behavior.
-            mDefaultBackCallback = new OnBackInvokedCallback() {
-                @Override
-                public void onBackInvoked() {
-                    navigateBack();
-                }
-            };
+            mDefaultBackCallback = this::navigateBack;
             getOnBackInvokedDispatcher().registerSystemOnBackInvokedCallback(mDefaultBackCallback);
         }
     }
diff --git a/core/java/android/app/Dialog.java b/core/java/android/app/Dialog.java
index 72c7fe4c5b40..51b71f0c5d52 100644
--- a/core/java/android/app/Dialog.java
+++ b/core/java/android/app/Dialog.java
@@ -459,12 +459,7 @@ public class Dialog implements DialogInterface, Window.Callback,
         if (mContext != null
                 && WindowOnBackInvokedDispatcher.isOnBackInvokedCallbackEnabled(mContext)) {
             // Add onBackPressed as default back behavior.
-            mDefaultBackCallback = new OnBackInvokedCallback() {
-                @Override
-                public void onBackInvoked() {
-                    onBackPressed();
-                }
-            };
+            mDefaultBackCallback = this::onBackPressed;
             getOnBackInvokedDispatcher().registerOnBackInvokedCallback(
                     OnBackInvokedDispatcher.PRIORITY_DEFAULT, mDefaultBackCallback);
             mDefaultBackCallback = null;
diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 931ae2748785..900aa23d0347 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -10765,12 +10765,9 @@ public final class ViewRootImpl implements ViewParent,
     }
 
     private void registerCompatOnBackInvokedCallback() {
-        mCompatOnBackInvokedCallback = new OnBackInvokedCallback() {
-            @Override
-            public void onBackInvoked() {
+        mCompatOnBackInvokedCallback = () -> {
                 sendBackKeyEvent(KeyEvent.ACTION_DOWN);
                 sendBackKeyEvent(KeyEvent.ACTION_UP);
-            }
         };
         mOnBackInvokedDispatcher.registerOnBackInvokedCallback(
                 OnBackInvokedDispatcher.PRIORITY_DEFAULT, mCompatOnBackInvokedCallback);
diff --git a/core/java/android/widget/Editor.java b/core/java/android/widget/Editor.java
index dbfcca9d632a..285a40779b90 100644
--- a/core/java/android/widget/Editor.java
+++ b/core/java/android/widget/Editor.java
@@ -240,12 +240,7 @@ public class Editor {
 
     private final boolean mHapticTextHandleEnabled;
     /** Handles OnBackInvokedCallback back dispatch */
-    private final OnBackInvokedCallback mBackCallback = new OnBackInvokedCallback() {
-        @Override
-        public void onBackInvoked() {
-            stopTextActionMode();
-        }
-    };
+    private final OnBackInvokedCallback mBackCallback = this::stopTextActionMode;
     private boolean mBackCallbackRegistered;
 
     @Nullable
diff --git a/core/java/android/widget/MediaController.java b/core/java/android/widget/MediaController.java
index f1dc5e7050fb..ab2d0056df6b 100644
--- a/core/java/android/widget/MediaController.java
+++ b/core/java/android/widget/MediaController.java
@@ -122,12 +122,7 @@ public class MediaController extends FrameLayout {
     private final AccessibilityManager mAccessibilityManager;
     private boolean mBackCallbackRegistered;
     /** Handles back invocation */
-    private final OnBackInvokedCallback mBackCallback = new OnBackInvokedCallback() {
-        @Override
-        public void onBackInvoked() {
-            hide();
-        }
-    };
+    private final OnBackInvokedCallback mBackCallback = this::hide;
     /** Handles decor view attach state change */
     private final OnAttachStateChangeListener mAttachStateListener =
             new OnAttachStateChangeListener() {
diff --git a/core/java/android/window/OnBackAnimationCallback.java b/core/java/android/window/OnBackAnimationCallback.java
new file mode 100644
index 000000000000..1a37e57df403
--- /dev/null
+++ b/core/java/android/window/OnBackAnimationCallback.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.window;
+
+import android.annotation.NonNull;
+import android.app.Activity;
+import android.app.Dialog;
+import android.view.View;
+
+/**
+ * Interface for applications to register back animation callbacks along their custom back
+ * handling.
+ * <p>
+ * This allows the client to customize various back behaviors by overriding the corresponding
+ * callback methods.
+ * <p>
+ * Callback instances can be added to and removed from {@link OnBackInvokedDispatcher}, held
+ * by classes that implement {@link OnBackInvokedDispatcherOwner} (such as {@link Activity},
+ * {@link Dialog} and {@link View}).
+ * <p>
+ * When back is triggered, callbacks on the in-focus window are invoked in reverse order in which
+ * they are added within the same priority. Between different priorities, callbacks with higher
+ * priority are invoked first.
+ * <p>
+ * @see OnBackInvokedCallback
+ * @hide
+ */
+public interface OnBackAnimationCallback extends OnBackInvokedCallback {
+   /**
+    * Called when a back gesture has been started, or back button has been pressed down.
+    */
+    default void onBackStarted() { }
+
+    /**
+     * Called on back gesture progress.
+     *
+     * @param backEvent An {@link BackEvent} object describing the progress event.
+     *
+     * @see BackEvent
+     */
+    default void onBackProgressed(@NonNull BackEvent backEvent) { }
+
+    /**
+     * Called when a back gesture or back button press has been cancelled.
+     */
+    default void onBackCancelled() { }
+}
diff --git a/core/java/android/window/OnBackInvokedCallback.java b/core/java/android/window/OnBackInvokedCallback.java
index 400a56f2c485..7b8cc0ae6de7 100644
--- a/core/java/android/window/OnBackInvokedCallback.java
+++ b/core/java/android/window/OnBackInvokedCallback.java
@@ -21,49 +21,29 @@ import android.app.Dialog;
 import android.view.View;
 
 /**
- * Interface for applications to register back invocation callbacks. This allows the client
- * to customize various back behaviors by overriding the corresponding callback methods.
- *
+ * Callback allowing applications to handle back events in place of the system.
+ * <p>
  * Callback instances can be added to and removed from {@link OnBackInvokedDispatcher}, held
  * by classes that implement {@link OnBackInvokedDispatcherOwner} (such as {@link Activity},
  * {@link Dialog} and {@link View}).
- *
+ * <p>
  * Under the hood callbacks are registered at window level. When back is triggered,
  * callbacks on the in-focus window are invoked in reverse order in which they are added
  * within the same priority. Between different pirorities, callbacks with higher priority
  * are invoked first.
+ * <p>
+ * This replaces {@link Activity#onBackPressed()}, {@link Dialog#onBackPressed()} and
+ * {@link android.view.KeyEvent#KEYCODE_BACK}
  *
- * See {@link OnBackInvokedDispatcher#registerOnBackInvokedCallback(int, OnBackInvokedCallback)}
- * for specifying callback priority.
+ * @see OnBackInvokedDispatcher#registerOnBackInvokedCallback(int, OnBackInvokedCallback)
+ * registerOnBackInvokedCallback(priority, OnBackInvokedCallback)
+ * to specify callback priority.
  */
+@SuppressWarnings("deprecation")
 public interface OnBackInvokedCallback {
-   /**
-    * Called when a back gesture has been started, or back button has been pressed down.
-    *
-    * @hide
-    */
-    default void onBackStarted() { };
-
-    /**
-     * Called on back gesture progress.
-     *
-     * @param backEvent An {@link android.window.BackEvent} object describing the progress event.
-     *
-     * @see android.window.BackEvent
-     * @hide
-     */
-    default void onBackProgressed(BackEvent backEvent) { };
-
-    /**
-     * Called when a back gesture or back button press has been cancelled.
-     *
-     * @hide
-     */
-    default void onBackCancelled() { };
-
     /**
      * Called when a back gesture has been completed and committed, or back button pressed
      * has been released and committed.
      */
-    default void onBackInvoked() { };
+    void onBackInvoked();
 }
diff --git a/core/java/android/window/WindowOnBackInvokedDispatcher.java b/core/java/android/window/WindowOnBackInvokedDispatcher.java
index 8811116b25ad..77031d93f943 100644
--- a/core/java/android/window/WindowOnBackInvokedDispatcher.java
+++ b/core/java/android/window/WindowOnBackInvokedDispatcher.java
@@ -199,36 +199,30 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
         @Override
         public void onBackStarted() {
             Handler.getMain().post(() -> {
-                final OnBackInvokedCallback callback = mCallback.get();
-                if (callback == null) {
-                    return;
+                final OnBackAnimationCallback callback = getBackAnimationCallback();
+                if (callback != null) {
+                    callback.onBackStarted();
                 }
-
-                callback.onBackStarted();
             });
         }
 
         @Override
         public void onBackProgressed(BackEvent backEvent) {
             Handler.getMain().post(() -> {
-                final OnBackInvokedCallback callback = mCallback.get();
-                if (callback == null) {
-                    return;
+                final OnBackAnimationCallback callback = getBackAnimationCallback();
+                if (callback != null) {
+                    callback.onBackProgressed(backEvent);
                 }
-
-                callback.onBackProgressed(backEvent);
             });
         }
 
         @Override
         public void onBackCancelled() {
             Handler.getMain().post(() -> {
-                final OnBackInvokedCallback callback = mCallback.get();
-                if (callback == null) {
-                    return;
+                final OnBackAnimationCallback callback = getBackAnimationCallback();
+                if (callback != null) {
+                    callback.onBackCancelled();
                 }
-
-                callback.onBackCancelled();
             });
         }
 
@@ -243,6 +237,13 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
                 callback.onBackInvoked();
             });
         }
+
+        @Nullable
+        private OnBackAnimationCallback getBackAnimationCallback() {
+            OnBackInvokedCallback callback = mCallback.get();
+            return callback instanceof OnBackAnimationCallback ? (OnBackAnimationCallback) callback
+                    : null;
+        }
     }
 
     /**