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Commit a567fea8 authored by Alejandro Nijamkin's avatar Alejandro Nijamkin
Browse files

Adds ViewTreeObserver window visibility listeners 

Follows the same exact pattern as the window attach and window focus
listeners in the same class.

Bug: 235403546
Test: Verified as part of follow-up systemui CLs
Change-Id: I7c825baf5913e6e0b85f475503639a4d17483d4e
parent 9e76e357

core/java/android/view/ViewRootImpl.java

+1 −0
Original line number Diff line number Diff line
@@ -2801,6 +2801,7 @@ public final class ViewRootImpl implements ViewParent, 
        if (viewVisibilityChanged) {

            mAttachInfo.mWindowVisibility = viewVisibility;

            host.dispatchWindowVisibilityChanged(viewVisibility);

            mAttachInfo.mTreeObserver.dispatchOnWindowVisibilityChange(viewVisibility);

            if (viewUserVisibilityChanged) {

                host.dispatchVisibilityAggregated(viewVisibility == View.VISIBLE);

            }

core/java/android/view/ViewTreeObserver.java

+84 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ public final class ViewTreeObserver { 
    // Recursive listeners use CopyOnWriteArrayList

    private CopyOnWriteArrayList<OnWindowFocusChangeListener> mOnWindowFocusListeners;

    private CopyOnWriteArrayList<OnWindowAttachListener> mOnWindowAttachListeners;

    private CopyOnWriteArrayList<OnWindowVisibilityChangeListener> mOnWindowVisibilityListeners;

    private CopyOnWriteArrayList<OnGlobalFocusChangeListener> mOnGlobalFocusListeners;

    @UnsupportedAppUsage

    private CopyOnWriteArrayList<OnTouchModeChangeListener> mOnTouchModeChangeListeners;
@@ -105,6 +106,21 @@ public final class ViewTreeObserver { 
        public void onWindowFocusChanged(boolean hasFocus);

    }



    /**

     * Interface definition for a callback to be invoked when the view hierarchy's window

     * visibility changes.

     *

     * @hide

     */

    public interface OnWindowVisibilityChangeListener {

        /**

         * Callback method to be invoked when the window visibility changes in the view tree.

         *

         * @param visibility The new visibility of the window.

         */

        void onWindowVisibilityChanged(@View.Visibility int visibility);

    }



    /**

     * Interface definition for a callback to be invoked when the focus state within

     * the view tree changes.
@@ -386,6 +402,14 @@ public final class ViewTreeObserver { 
            }

        }



        if (observer.mOnWindowVisibilityListeners != null) {

            if (mOnWindowVisibilityListeners != null) {

                mOnWindowVisibilityListeners.addAll(observer.mOnWindowVisibilityListeners);

            } else {

                mOnWindowVisibilityListeners = observer.mOnWindowVisibilityListeners;

            }

        }



        if (observer.mOnGlobalFocusListeners != null) {

            if (mOnGlobalFocusListeners != null) {

                mOnGlobalFocusListeners.addAll(observer.mOnGlobalFocusListeners);
@@ -540,6 +564,49 @@ public final class ViewTreeObserver { 
    }



    /**

     * Register a callback to be invoked when the window visibility changes.

     *

     * @param listener The callback to add

     *

     * @throws IllegalStateException If {@link #isAlive()} returns false

     *

     * @hide

     */

    public void addOnWindowVisibilityChangeListener(

            @NonNull OnWindowVisibilityChangeListener listener) {

        checkIsAlive();



        if (mOnWindowVisibilityListeners == null) {

            mOnWindowVisibilityListeners =

                new CopyOnWriteArrayList<OnWindowVisibilityChangeListener>();

        }



        mOnWindowVisibilityListeners.add(listener);

    }



    /**

     * Remove a previously installed window visibility callback.

     *

     * @param victim The callback to remove

     *

     * @throws IllegalStateException If {@link #isAlive()} returns false

     *

     * @see #addOnWindowVisibilityChangeListener(

     * android.view.ViewTreeObserver.OnWindowVisibilityChangeListener)

     *

     * @hide

     */

    public void removeOnWindowVisibilityChangeListener(

            @NonNull OnWindowVisibilityChangeListener victim) {

        checkIsAlive();

        if (mOnWindowVisibilityListeners == null) {

            return;

        }



        mOnWindowVisibilityListeners.remove(victim);

    }



    /*

     * Register a callback to be invoked when the focus state within the view tree changes.

     *

     * @param listener The callback to add
@@ -1025,6 +1092,23 @@ public final class ViewTreeObserver { 
        }

    }



    /**

     * Notifies registered listeners that window visibility has changed.

     */

    void dispatchOnWindowVisibilityChange(int visibility) {

        // NOTE: because of the use of CopyOnWriteArrayList, we *must* use an iterator to

        // perform the dispatching. The iterator is a safe guard against listeners that

        // could mutate the list by calling the various add/remove methods. This prevents

        // the array from being modified while we iterate it.

        final CopyOnWriteArrayList<OnWindowVisibilityChangeListener> listeners =

                mOnWindowVisibilityListeners;

        if (listeners != null && listeners.size() > 0) {

            for (OnWindowVisibilityChangeListener listener : listeners) {

                listener.onWindowVisibilityChanged(visibility);

            }

        }

    }



    /**

     * Notifies registered listeners that focus has changed.

     */