Merge "Refactor listener to centralize value logic." into main

2 files changed, 20 insertions, 9 deletions

diff --git a/core/java/android/view/translation/ListenerGroup.java b/core/java/android/view/ListenerGroup.java
index 5c70805042fa..889caec3f5d1 100644
--- a/core/java/android/view/translation/ListenerGroup.java
+++ b/core/java/android/view/ListenerGroup.java
@@ -14,10 +14,9 @@
  * limitations under the License.
  */
 
-package android.view.translation;
+package android.view;
 
 import android.annotation.NonNull;
-import android.view.ListenerWrapper;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -32,26 +31,39 @@ import java.util.function.Consumer;
  */
 public class ListenerGroup<T> {
     private final List<ListenerWrapper<T>> mListeners = new ArrayList<>();
+    @NonNull
+    private T mLastValue;
+
+    /**
+     * Constructs a {@link ListenerGroup} that will replay the last reported value whenever a new
+     * listener is registered.
+     * @param value the initial value
+     */
+    public ListenerGroup(@NonNull T value) {
+        mLastValue = value;
+    }
 
     /**
      * Relays the value to all the registered {@link java.util.function.Consumer}
      */
     public void accept(@NonNull T value) {
-        Objects.requireNonNull(value);
+        mLastValue = Objects.requireNonNull(value);
         for (int i = 0; i < mListeners.size(); i++) {
             mListeners.get(i).accept(value);
         }
     }
 
     /**
-     * Adds a {@link Consumer} to the group. If the {@link Consumer} is already present then this
-     * is a no op.
+     * Adds a {@link Consumer} to the group and replays the last reported value. If the
+     * {@link Consumer} is already present then this is a no op.
      */
     public void addListener(@NonNull Executor executor, @NonNull Consumer<T> consumer) {
         if (isConsumerPresent(consumer)) {
             return;
         }
-        mListeners.add(new ListenerWrapper<>(executor, consumer));
+        final ListenerWrapper<T> listenerWrapper = new ListenerWrapper<>(executor, consumer);
+        mListeners.add(listenerWrapper);
+        listenerWrapper.accept(mLastValue);
     }
 
     /**
diff --git a/core/java/android/view/WindowManagerGlobal.java b/core/java/android/view/WindowManagerGlobal.java
index b97f28da7559..5fdb387c0f73 100644
--- a/core/java/android/view/WindowManagerGlobal.java
+++ b/core/java/android/view/WindowManagerGlobal.java
@@ -44,7 +44,6 @@ import android.util.Log;
 import android.util.Pair;
 import android.util.SparseArray;
 import android.view.inputmethod.InputMethodManager;
-import android.view.translation.ListenerGroup;
 import android.window.ITrustedPresentationListener;
 import android.window.InputTransferToken;
 import android.window.TrustedPresentationThresholds;
@@ -154,7 +153,8 @@ public final class WindowManagerGlobal {
      * @hide
      */
     @GuardedBy("mLock")
-    private final ListenerGroup<List<View>> mWindowViewsListenerGroup = new ListenerGroup<>();
+    private final ListenerGroup<List<View>> mWindowViewsListenerGroup =
+            new ListenerGroup<>(new ArrayList<>());
     @UnsupportedAppUsage
     private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>();
     @UnsupportedAppUsage
@@ -339,7 +339,6 @@ public final class WindowManagerGlobal {
                 return;
             }
             mWindowViewsListenerGroup.addListener(executor, consumer);
-            executor.execute(() -> consumer.accept(getWindowViews()));
         }
     }