1 files changed, 58 insertions, 5 deletions
diff --git a/core/java/android/window/WindowOnBackInvokedDispatcher.java b/core/java/android/window/WindowOnBackInvokedDispatcher.java
index 1d0bc5a6f0ba..d147524d3b3d 100644
--- a/core/java/android/window/WindowOnBackInvokedDispatcher.java
+++ b/core/java/android/window/WindowOnBackInvokedDispatcher.java
@@ -30,6 +30,7 @@ import android.view.IWindowSession;
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Objects;
 import java.util.TreeMap;
 
 /**
@@ -62,6 +63,11 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
     /** Holds all callbacks by priorities. */
     private final TreeMap<Integer, ArrayList<OnBackInvokedCallback>>
             mOnBackInvokedCallbacks = new TreeMap<>();
+    private final Checker mChecker;
+
+    public WindowOnBackInvokedDispatcher(boolean applicationCallBackEnabled) {
+        mChecker = new Checker(applicationCallBackEnabled);
+    }
 
     /**
      * Sends the pending top callback (if one exists) to WM when the view root
@@ -86,14 +92,16 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
     @Override
     public void registerOnBackInvokedCallback(
             @Priority int priority, @NonNull OnBackInvokedCallback callback) {
-        if (priority < 0) {
-            throw new IllegalArgumentException("Application registered OnBackInvokedCallback "
-                    + "cannot have negative priority. Priority: " + priority);
+        if (mChecker.checkApplicationCallbackRegistration(priority, callback)) {
+            registerOnBackInvokedCallbackUnchecked(callback, priority);
         }
-        registerOnBackInvokedCallbackUnchecked(callback, priority);
     }
 
-    private void registerOnBackInvokedCallbackUnchecked(
+    /**
+     * Register a callback bypassing platform checks. This is used to register compatibility
+     * callbacks.
+     */
+    public void registerOnBackInvokedCallbackUnchecked(
             @NonNull OnBackInvokedCallback callback, @Priority int priority) {
         if (mImeDispatcher != null) {
             mImeDispatcher.registerOnBackInvokedCallback(priority, callback);
@@ -203,6 +211,14 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
         return null;
     }
 
+    /**
+     * Returns the checker used to check whether a callback can be registered
+     */
+    @NonNull
+    public Checker getChecker() {
+        return mChecker;
+    }
+
     static class OnBackInvokedCallbackWrapper extends IOnBackInvokedCallback.Stub {
         private final WeakReference<OnBackInvokedCallback> mCallback;
 
@@ -289,4 +305,41 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
             @NonNull ImeOnBackInvokedDispatcher imeDispatcher) {
         mImeDispatcher = imeDispatcher;
     }
+
+
+    /**
+     * Class used to check whether a callback can be registered or not. This is meant to be
+     * shared with {@link ProxyOnBackInvokedDispatcher} which needs to do the same checks.
+     */
+    public static class Checker {
+
+        private final boolean mApplicationCallBackEnabled;
+
+        public Checker(boolean applicationCallBackEnabled) {
+            mApplicationCallBackEnabled = applicationCallBackEnabled;
+        }
+
+        /**
+         * Checks whether the given callback can be registered with the given priority.
+         * @return true if the callback can be added.
+         * @throws IllegalArgumentException if the priority is negative.
+         */
+        public boolean checkApplicationCallbackRegistration(int priority,
+                OnBackInvokedCallback callback) {
+            if (!mApplicationCallBackEnabled
+                    && !(callback instanceof CompatOnBackInvokedCallback)) {
+                Log.w("OnBackInvokedCallback",
+                        "OnBackInvokedCallback is not enabled for the application."
+                                + "\nSet 'android:enableOnBackInvokedCallback=\"true\"' in the"
+                                + " application manifest.");
+                return false;
+            }
+            if (priority < 0) {
+                throw new IllegalArgumentException("Application registered OnBackInvokedCallback "
+                        + "cannot have negative priority. Priority: " + priority);
+            }
+            Objects.requireNonNull(callback);
+            return true;
+        }
+    }
 }