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

1 files changed, 61 insertions, 0 deletions

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() { }
+}