Accessibility focus traversal in virtual nodes.

1. Finished the implementation of support for maintaining
   accessibility focus in view with virtual descendants.

2. Finished the NumberPicker implementation of virtual
   subtree such that all requred attributes are reported
   and ensuring that it support accessibility focus in
   its virtual descentants.

3. Fixed a bug where if a predecessor of the view that is
   accessiiblity focused is removed the accessibliity focus
   host in ViewRootImpl is not cleared leading to a crash
   when trying to draw the accessibility focus highlight.:

bug:6472646
bug:6433864

Change-Id: I3645642b87b4a26025c0b2ba9dfaad92d11a48f1

1 files changed, 242 insertions, 12 deletions

diff --git a/core/java/android/widget/NumberPicker.java b/core/java/android/widget/NumberPicker.java
index 7c809b3d2b30..78d570e9d3eb 100644
--- a/core/java/android/widget/NumberPicker.java
+++ b/core/java/android/widget/NumberPicker.java
@@ -950,6 +950,8 @@ public class NumberPicker extends LinearLayout {
                     provider.sendAccessibilityEventForVirtualView(hoveredVirtualViewId,
                             AccessibilityEvent.TYPE_VIEW_HOVER_ENTER);
                     mLastHoveredChildVirtualViewId = hoveredVirtualViewId;
+                    provider.performAction(hoveredVirtualViewId,
+                            AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null);
                 } break;
                 case MotionEvent.ACTION_HOVER_MOVE: {
                     if (mLastHoveredChildVirtualViewId != hoveredVirtualViewId
@@ -960,6 +962,8 @@ public class NumberPicker extends LinearLayout {
                         provider.sendAccessibilityEventForVirtualView(hoveredVirtualViewId,
                                 AccessibilityEvent.TYPE_VIEW_HOVER_ENTER);
                         mLastHoveredChildVirtualViewId = hoveredVirtualViewId;
+                        provider.performAction(hoveredVirtualViewId,
+                                AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null);
                     }
                 } break;
                 case MotionEvent.ACTION_HOVER_EXIT: {
@@ -1413,9 +1417,16 @@ public class NumberPicker extends LinearLayout {
     }
 
     @Override
-    public void sendAccessibilityEvent(int eventType) {
-        // Do not send accessibility events - we want the user to
-        // perceive this widget as several controls rather as a whole.
+    public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
+        // We do not want the real descendant to be considered focus search
+        // since it is managed by the accessibility node provider.
+        if ((focusableMode & FOCUSABLES_ACCESSIBILITY) == FOCUSABLES_ACCESSIBILITY) {
+            if (canTakeAccessibilityFocusFromHover() || getAccessibilityNodeProvider() != null) {
+                views.add(this);
+                return;
+            }
+        }
+        super.addFocusables(views, direction, focusableMode);
     }
 
     @Override
@@ -2072,7 +2083,12 @@ public class NumberPicker extends LinearLayout {
         }
     }
 
+    /**
+     * Class for managing virtual view tree rooted at this picker.
+     */
     class AccessibilityNodeProviderImpl extends AccessibilityNodeProvider {
+        private static final int UNDEFINED = Integer.MIN_VALUE;
+
         private static final int VIRTUAL_VIEW_ID_INCREMENT = 1;
 
         private static final int VIRTUAL_VIEW_ID_INPUT = 2;
@@ -2083,6 +2099,8 @@ public class NumberPicker extends LinearLayout {
 
         private final int[] mTempArray = new int[2];
 
+        private int mAccessibilityFocusedView = UNDEFINED;
+
         @Override
         public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId) {
             switch (virtualViewId) {
@@ -2137,6 +2155,25 @@ public class NumberPicker extends LinearLayout {
         @Override
         public boolean performAction(int virtualViewId, int action, Bundle arguments) {
             switch (virtualViewId) {
+                case View.NO_ID: {
+                    switch (action) {
+                        case AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView != virtualViewId) {
+                                mAccessibilityFocusedView = virtualViewId;
+                                requestAccessibilityFocus();
+                                return true;
+                            }
+                        } return false;
+                        case AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView == virtualViewId) {
+                                mAccessibilityFocusedView = UNDEFINED;
+                                clearAccessibilityFocus();
+                                return true;
+                            }
+                            return false;
+                        }
+                    }
+                } break;
                 case VIRTUAL_VIEW_ID_INPUT: {
                     switch (action) {
                         case AccessibilityNodeInfo.ACTION_FOCUS: {
@@ -2149,25 +2186,182 @@ public class NumberPicker extends LinearLayout {
                                 mInputText.clearFocus();
                                 return true;
                             }
-                        } break;
+                            return false;
+                        }
+                        case AccessibilityNodeInfo.ACTION_CLICK: {
+                            showSoftInput();
+                            return true;
+                        }
+                        case AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView != virtualViewId) {
+                                mAccessibilityFocusedView = virtualViewId;
+                                sendAccessibilityEventForVirtualView(virtualViewId,
+                                        AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+                                mInputText.invalidate();
+                                return true;
+                            }
+                        } return false;
+                        case  AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView == virtualViewId) {
+                                mAccessibilityFocusedView = UNDEFINED;
+                                sendAccessibilityEventForVirtualView(virtualViewId,
+                                        AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
+                                mInputText.invalidate();
+                                return true;
+                            }
+                        } return false;
+                        default: {
+                            return mInputText.performAccessibilityAction(action, arguments);
+                        }
                     }
-                } break;
+                } return false;
+                case VIRTUAL_VIEW_ID_INCREMENT: {
+                    switch (action) {
+                        case AccessibilityNodeInfo.ACTION_CLICK: {
+                            NumberPicker.this.changeValueByOne(true);
+                            sendAccessibilityEventForVirtualView(virtualViewId,
+                                    AccessibilityEvent.TYPE_VIEW_CLICKED);
+                        } return true;
+                        case AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView != virtualViewId) {
+                                mAccessibilityFocusedView = virtualViewId;
+                                sendAccessibilityEventForVirtualView(virtualViewId,
+                                        AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+                                invalidate(0, mBottomSelectionDividerBottom, mRight, mBottom);
+                                return true;
+                            }
+                        } return false;
+                        case  AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView == virtualViewId) {
+                                mAccessibilityFocusedView = UNDEFINED;
+                                sendAccessibilityEventForVirtualView(virtualViewId,
+                                        AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
+                                invalidate(0, mBottomSelectionDividerBottom, mRight, mBottom);
+                                return true;
+                            }
+                        } return false;
+                    }
+                } return false;
+                case VIRTUAL_VIEW_ID_DECREMENT: {
+                    switch (action) {
+                        case AccessibilityNodeInfo.ACTION_CLICK: {
+                            final boolean increment = (virtualViewId == VIRTUAL_VIEW_ID_INCREMENT);
+                            NumberPicker.this.changeValueByOne(increment);
+                            sendAccessibilityEventForVirtualView(virtualViewId,
+                                    AccessibilityEvent.TYPE_VIEW_CLICKED);
+                        } return true;
+                        case AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView != virtualViewId) {
+                                mAccessibilityFocusedView = virtualViewId;
+                                sendAccessibilityEventForVirtualView(virtualViewId,
+                                        AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED);
+                                invalidate(0, 0, mRight, mTopSelectionDividerTop);
+                                return true;
+                            }
+                        } return false;
+                        case  AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS: {
+                            if (mAccessibilityFocusedView == virtualViewId) {
+                                mAccessibilityFocusedView = UNDEFINED;
+                                sendAccessibilityEventForVirtualView(virtualViewId,
+                                        AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED);
+                                invalidate(0, 0, mRight, mTopSelectionDividerTop);
+                                return true;
+                            }
+                        } return false;
+                    }
+                } return false;
             }
             return super.performAction(virtualViewId, action, arguments);
         }
 
+        @Override
+        public AccessibilityNodeInfo findAccessibilityFocus(int virtualViewId) {
+            return createAccessibilityNodeInfo(mAccessibilityFocusedView);
+        }
+
+        @Override
+        public AccessibilityNodeInfo accessibilityFocusSearch(int direction, int virtualViewId) {
+            switch (direction) {
+                case View.ACCESSIBILITY_FOCUS_DOWN:
+                case View.ACCESSIBILITY_FOCUS_FORWARD: {
+                    switch (mAccessibilityFocusedView) {
+                        case UNDEFINED: {
+                            return createAccessibilityNodeInfo(View.NO_ID);
+                        }
+                        case View.NO_ID: {
+                            if (hasVirtualDecrementButton()) {
+                                return createAccessibilityNodeInfo(VIRTUAL_VIEW_ID_DECREMENT);
+                            }
+                        }
+                        //$FALL-THROUGH$
+                        case VIRTUAL_VIEW_ID_DECREMENT: {
+                            return createAccessibilityNodeInfo(VIRTUAL_VIEW_ID_INPUT);
+                        }
+                        case VIRTUAL_VIEW_ID_INPUT: {
+                            if (hasVirtualIncrementButton()) {
+                                return createAccessibilityNodeInfo(VIRTUAL_VIEW_ID_INCREMENT);
+                            }
+                        }
+                        //$FALL-THROUGH$
+                        case VIRTUAL_VIEW_ID_INCREMENT: {
+                            View nextFocus = NumberPicker.this.focusSearch(direction);
+                            if (nextFocus != null) {
+                                return nextFocus.createAccessibilityNodeInfo();
+                            }
+                            return null;
+                        }
+                    }
+                } break;
+                case View.ACCESSIBILITY_FOCUS_UP:
+                case View.ACCESSIBILITY_FOCUS_BACKWARD: {
+                    switch (mAccessibilityFocusedView) {
+                        case UNDEFINED: {
+                            return createAccessibilityNodeInfo(View.NO_ID);
+                        }
+                        case View.NO_ID: {
+                            if (hasVirtualIncrementButton()) {
+                                return createAccessibilityNodeInfo(VIRTUAL_VIEW_ID_INCREMENT);
+                            }
+                        }
+                        //$FALL-THROUGH$
+                        case VIRTUAL_VIEW_ID_INCREMENT: {
+                            return createAccessibilityNodeInfo(VIRTUAL_VIEW_ID_INPUT);
+                        }
+                        case VIRTUAL_VIEW_ID_INPUT: {
+                            if (hasVirtualDecrementButton()) {
+                                return createAccessibilityNodeInfo(VIRTUAL_VIEW_ID_DECREMENT);
+                            }
+                        }
+                        //$FALL-THROUGH$
+                        case VIRTUAL_VIEW_ID_DECREMENT: {
+                            View nextFocus = NumberPicker.this.focusSearch(direction);
+                            if (nextFocus != null) {
+                                return nextFocus.createAccessibilityNodeInfo();
+                            }
+                            return null;
+                        }
+                    }
+                } break;
+            }
+            return null;
+        }
+
         public void sendAccessibilityEventForVirtualView(int virtualViewId, int eventType) {
             switch (virtualViewId) {
                 case VIRTUAL_VIEW_ID_DECREMENT: {
-                    sendAccessibilityEventForVirtualButton(virtualViewId, eventType,
-                            getVirtualDecrementButtonText());
+                    if (hasVirtualDecrementButton()) {
+                        sendAccessibilityEventForVirtualButton(virtualViewId, eventType,
+                                getVirtualDecrementButtonText());
+                    }
                 } break;
                 case VIRTUAL_VIEW_ID_INPUT: {
                     sendAccessibilityEventForVirtualText(eventType);
                 } break;
                 case VIRTUAL_VIEW_ID_INCREMENT: {
-                    sendAccessibilityEventForVirtualButton(virtualViewId, eventType,
-                            getVirtualIncrementButtonText());
+                    if (hasVirtualIncrementButton()) {
+                        sendAccessibilityEventForVirtualButton(virtualViewId, eventType,
+                                getVirtualIncrementButtonText());
+                    }
                 } break;
             }
         }
@@ -2227,8 +2421,13 @@ public class NumberPicker extends LinearLayout {
 
         private AccessibilityNodeInfo createAccessibiltyNodeInfoForInputText() {
             AccessibilityNodeInfo info = mInputText.createAccessibilityNodeInfo();
-            info.setLongClickable(true);
             info.setSource(NumberPicker.this, VIRTUAL_VIEW_ID_INPUT);
+            if (mAccessibilityFocusedView != VIRTUAL_VIEW_ID_INPUT) {
+                info.addAction(AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS);
+            }
+            if (mAccessibilityFocusedView == VIRTUAL_VIEW_ID_INPUT) {
+                info.addAction(AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS);
+            }
             return info;
         }
 
@@ -2252,6 +2451,15 @@ public class NumberPicker extends LinearLayout {
             getLocationOnScreen(locationOnScreen);
             boundsInScreen.offset(locationOnScreen[0], locationOnScreen[1]);
             info.setBoundsInScreen(boundsInScreen);
+
+            if (mAccessibilityFocusedView != virtualViewId) {
+                info.addAction(AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS);
+            }
+            if (mAccessibilityFocusedView == virtualViewId) {
+                info.addAction(AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS);
+            }
+            info.addAction(AccessibilityNodeInfo.ACTION_CLICK);
+
             return info;
         }
 
@@ -2261,9 +2469,15 @@ public class NumberPicker extends LinearLayout {
             info.setClassName(NumberPicker.class.getName());
             info.setPackageName(mContext.getPackageName());
             info.setSource(NumberPicker.this);
-            info.addChild(NumberPicker.this, VIRTUAL_VIEW_ID_DECREMENT);
+
+            if (hasVirtualDecrementButton()) {
+                info.addChild(NumberPicker.this, VIRTUAL_VIEW_ID_DECREMENT);
+            }
             info.addChild(NumberPicker.this, VIRTUAL_VIEW_ID_INPUT);
-            info.addChild(NumberPicker.this, VIRTUAL_VIEW_ID_INCREMENT);
+            if (hasVirtualIncrementButton()) {
+                info.addChild(NumberPicker.this, VIRTUAL_VIEW_ID_INCREMENT);
+            }
+
             info.setParent((View) getParent());
             info.setEnabled(NumberPicker.this.isEnabled());
             info.setScrollable(true);
@@ -2276,9 +2490,25 @@ public class NumberPicker extends LinearLayout {
             getLocationOnScreen(locationOnScreen);
             boundsInScreen.offset(locationOnScreen[0], locationOnScreen[1]);
             info.setBoundsInScreen(boundsInScreen);
+
+            if (mAccessibilityFocusedView != View.NO_ID) {
+                info.addAction(AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS);
+            }
+            if (mAccessibilityFocusedView == View.NO_ID) {
+                info.addAction(AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS);
+            }
+
             return info;
         }
 
+        private boolean hasVirtualDecrementButton() {
+            return getWrapSelectorWheel() || getValue() > getMinValue();
+        }
+
+        private boolean hasVirtualIncrementButton() {
+            return getWrapSelectorWheel() || getValue() < getMaxValue();
+        }
+
         private String getVirtualDecrementButtonText() {
             int value = mValue - 1;
             if (mWrapSelectorWheel) {