add directional accessibility page actions to StackView

StackView has ITEMS_SLIDE_UP mode and ITEMS_SLIDE_DOWN mode. In
ITEMS_SLIDE_UP mode, scroll forward is slide up and all pages go up
(page down action), scroll backward is slide down and all pages go down
(page up action). In ITEMS_SLIDE_DOWN mode, it is the opposite.
A video in ITEMS_SLIDE_UP MODE is here:
https://drive.google.com/file/d/1m5awAP7ja8tqSaSvNM_oDoVbaUeCa3l6/view?usp=sharing

Test: Tested with twisted talkback that in ITEMS_SLIDE_DOWN mode, page
down action is equivalent to scroll backward, and page up is equivalent
to scroll forward.
Bug: 136277517

Change-Id: I52b2af231781fa04cec5815db2e573a9014e434b

1 files changed, 47 insertions, 11 deletions

diff --git a/core/java/android/widget/StackView.java b/core/java/android/widget/StackView.java
index 5091eea1898d..ad3563316854 100644
--- a/core/java/android/widget/StackView.java
+++ b/core/java/android/widget/StackView.java
@@ -42,6 +42,8 @@ import android.view.accessibility.AccessibilityNodeInfo;
 import android.view.animation.LinearInterpolator;
 import android.widget.RemoteViews.RemoteView;
 
+import com.android.internal.R;
+
 import java.lang.ref.WeakReference;
 
 @RemoteView
@@ -1241,14 +1243,40 @@ public class StackView extends AdapterViewAnimator {
         info.setScrollable(getChildCount() > 1);
         if (isEnabled()) {
             if (getDisplayedChild() < getChildCount() - 1) {
-                info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD);
+                info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_FORWARD);
+                if (mStackMode == ITEMS_SLIDE_UP) {
+                    info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_DOWN);
+                } else {
+                    info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_UP);
+                }
             }
             if (getDisplayedChild() > 0) {
-                info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD);
+                info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_BACKWARD);
+                if (mStackMode == ITEMS_SLIDE_UP) {
+                    info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_UP);
+                } else {
+                    info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_DOWN);
+                }
             }
         }
     }
 
+    private boolean goForward() {
+        if (getDisplayedChild() < getChildCount() - 1) {
+            showNext();
+            return true;
+        }
+        return false;
+    }
+
+    private boolean goBackward() {
+        if (getDisplayedChild() > 0) {
+            showPrevious();
+            return true;
+        }
+        return false;
+    }
+
     /** @hide */
     @Override
     public boolean performAccessibilityActionInternal(int action, Bundle arguments) {
@@ -1260,17 +1288,25 @@ public class StackView extends AdapterViewAnimator {
         }
         switch (action) {
             case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: {
-                if (getDisplayedChild() < getChildCount() - 1) {
-                    showNext();
-                    return true;
-                }
-            } return false;
+                return goForward();
+            }
             case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: {
-                if (getDisplayedChild() > 0) {
-                    showPrevious();
-                    return true;
+                return goBackward();
+            }
+            case R.id.accessibilityActionPageUp: {
+                if (mStackMode == ITEMS_SLIDE_UP) {
+                    return goBackward();
+                } else {
+                    return goForward();
+                }
+            }
+            case R.id.accessibilityActionPageDown: {
+                if (mStackMode == ITEMS_SLIDE_UP) {
+                    return goForward();
+                } else {
+                    return goBackward();
                 }
-            } return false;
+            }
         }
         return false;
     }