Ensure listener is not triggered when reregistered

Ensure a listener is not reregistered a second time.
Ensure the listener does not get a repeat value.
Update the javadocs for addGlobalWindowViewsListener to clear up
confusion. Fix some typos.

Flag: android.view.flags.root_view_changed_listener
Bug: 401234449
Test: atest CtsViewTestCases
Change-Id: Icaaee0db756884f90409e07c0f088b04afba4ce3

3 files changed, 11 insertions, 6 deletions

diff --git a/core/java/android/view/WindowManagerGlobal.java b/core/java/android/view/WindowManagerGlobal.java
index 624216776f42..b97f28da7559 100644
--- a/core/java/android/view/WindowManagerGlobal.java
+++ b/core/java/android/view/WindowManagerGlobal.java
@@ -329,13 +329,17 @@ public final class WindowManagerGlobal {
 
     /**
      * Adds a listener that will be notified whenever {@link #getWindowViews()} changes. The
-     * current value is provided immediately. If it was registered previously then this is ano op.
+     * current value is provided immediately using the provided {@link Executor}. If this
+     * {@link Consumer} was registered previously, then this is a no op.
      */
     public void addWindowViewsListener(@NonNull Executor executor,
             @NonNull Consumer<List<View>> consumer) {
         synchronized (mLock) {
+            if (mWindowViewsListenerGroup.isConsumerPresent(consumer)) {
+                return;
+            }
             mWindowViewsListenerGroup.addListener(executor, consumer);
-            mWindowViewsListenerGroup.accept(getWindowViews());
+            executor.execute(() -> consumer.accept(getWindowViews()));
         }
     }
 
diff --git a/core/java/android/view/inspector/WindowInspector.java b/core/java/android/view/inspector/WindowInspector.java
index 3ebca3c9d9b6..f0cc01133e07 100644
--- a/core/java/android/view/inspector/WindowInspector.java
+++ b/core/java/android/view/inspector/WindowInspector.java
@@ -42,8 +42,9 @@ public final class WindowInspector {
     }
 
     /**
-     * Adds a listener that is notified whenever the list of global window views changes. If a
-     * {@link Consumer} is already registered this method is a no op.
+     * Adds a listener that is notified whenever the value of {@link #getGlobalWindowViews()}
+     * changes. The current value is provided immediately using the provided {@link Executor}.
+     * If this {@link Consumer} is already registered, then this method is a no op.
      * @see #getGlobalWindowViews()
      */
     @FlaggedApi(android.view.flags.Flags.FLAG_ROOT_VIEW_CHANGED_LISTENER)
diff --git a/core/java/android/view/translation/ListenerGroup.java b/core/java/android/view/translation/ListenerGroup.java
index bf506815f841..5c70805042fa 100644
--- a/core/java/android/view/translation/ListenerGroup.java
+++ b/core/java/android/view/translation/ListenerGroup.java
@@ -48,7 +48,7 @@ public class ListenerGroup<T> {
      * is a no op.
      */
     public void addListener(@NonNull Executor executor, @NonNull Consumer<T> consumer) {
-        if (isContained(consumer)) {
+        if (isConsumerPresent(consumer)) {
             return;
         }
         mListeners.add(new ListenerWrapper<>(executor, consumer));
@@ -69,7 +69,7 @@ public class ListenerGroup<T> {
      * Returns {@code true} if the {@link Consumer} is present in the list, {@code false}
      * otherwise.
      */
-    private boolean isContained(Consumer<T> consumer) {
+    public boolean isConsumerPresent(Consumer<T> consumer) {
         return computeIndex(consumer) > -1;
     }