NumberPicker a11y (and a11y-inspired) fixes

- Sending scroll events for accessibility.
- Sending text update events when state changes.
- Blocking text updates during fling to reduce number of events.
- Making widget focusable by default, which keeps focus from
  moving to the rest of the UI when the text box becomes invisible.
- Managing visibility of the text box alongside IME state, so the
  IME won't decide to display the password keyboard during a fling.

Bug: 21494380
Bug: 37016501
Test: Ran NumberPicker CTS
Change-Id: I459d37d4a54c91e1cb5c7ec68fe0f012b25fb740

1 files changed, 38 insertions, 11 deletions

diff --git a/core/java/android/widget/NumberPicker.java b/core/java/android/widget/NumberPicker.java
index 7bdd6dadf415..d456989eb50a 100644
--- a/core/java/android/widget/NumberPicker.java
+++ b/core/java/android/widget/NumberPicker.java
@@ -737,6 +737,7 @@ public class NumberPicker extends LinearLayout {
         mInputText.setFilters(new InputFilter[] {
             new InputTextFilter()
         });
+        mInputText.setAccessibilityLiveRegion(View.ACCESSIBILITY_LIVE_REGION_POLITE);
 
         mInputText.setRawInputType(InputType.TYPE_CLASS_NUMBER);
         mInputText.setImeOptions(EditorInfo.IME_ACTION_DONE);
@@ -770,6 +771,12 @@ public class NumberPicker extends LinearLayout {
         if (getImportantForAccessibility() == IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
             setImportantForAccessibility(IMPORTANT_FOR_ACCESSIBILITY_YES);
         }
+
+        // Should be focusable by default, as the text view whose visibility changes is focusable
+        if (getFocusable() == View.FOCUSABLE_AUTO) {
+            setFocusable(View.FOCUSABLE);
+            setFocusableInTouchMode(true);
+        }
     }
 
     @Override
@@ -856,7 +863,7 @@ public class NumberPicker extends LinearLayout {
         switch (action) {
             case MotionEvent.ACTION_DOWN: {
                 removeAllCallbacks();
-                mInputText.setVisibility(View.INVISIBLE);
+                hideSoftInput();
                 mLastDownOrMoveEventY = mLastDownEventY = event.getY();
                 mLastDownEventTime = event.getEventTime();
                 mIgnoreMoveEvents = false;
@@ -883,11 +890,9 @@ public class NumberPicker extends LinearLayout {
                     mFlingScroller.forceFinished(true);
                     mAdjustScroller.forceFinished(true);
                 } else if (mLastDownEventY < mTopSelectionDividerTop) {
-                    hideSoftInput();
                     postChangeCurrentByOneFromLongPress(
                             false, ViewConfiguration.getLongPressTimeout());
                 } else if (mLastDownEventY > mBottomSelectionDividerBottom) {
-                    hideSoftInput();
                     postChangeCurrentByOneFromLongPress(
                             true, ViewConfiguration.getLongPressTimeout());
                 } else {
@@ -1120,6 +1125,7 @@ public class NumberPicker extends LinearLayout {
     @Override
     public void scrollBy(int x, int y) {
         int[] selectorIndices = mSelectorIndices;
+        int startScrollOffset = mCurrentScrollOffset;
         if (!mWrapSelectorWheel && y > 0
                 && selectorIndices[SELECTOR_MIDDLE_ITEM_INDEX] <= mMinValue) {
             mCurrentScrollOffset = mInitialScrollOffset;
@@ -1147,6 +1153,9 @@ public class NumberPicker extends LinearLayout {
                 mCurrentScrollOffset = mInitialScrollOffset;
             }
         }
+        if (startScrollOffset != mCurrentScrollOffset) {
+            onScrollChanged(0, mCurrentScrollOffset, 0, startScrollOffset);
+        }
     }
 
     @Override
@@ -1735,7 +1744,10 @@ public class NumberPicker extends LinearLayout {
         }
         int previous = mValue;
         mValue = current;
-        updateInputTextView();
+        // If we're flinging, we'll update the text view at the end when it becomes visible
+        if (mScrollState != OnScrollListener.SCROLL_STATE_FLING) {
+            updateInputTextView();
+        }
         if (notifyChange) {
             notifyChange(previous, current);
         }
@@ -1752,7 +1764,7 @@ public class NumberPicker extends LinearLayout {
      */
      private void changeValueByOne(boolean increment) {
         if (mHasSelectorWheel) {
-            mInputText.setVisibility(View.INVISIBLE);
+            hideSoftInput();
             if (!moveToFinalScrollerPosition(mFlingScroller)) {
                 moveToFinalScrollerPosition(mAdjustScroller);
             }
@@ -1799,9 +1811,8 @@ public class NumberPicker extends LinearLayout {
      */
     private void onScrollerFinished(Scroller scroller) {
         if (scroller == mFlingScroller) {
-            if (!ensureScrollWheelAdjusted()) {
-                updateInputTextView();
-            }
+            ensureScrollWheelAdjusted();
+            updateInputTextView();
             onScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);
         } else {
             if (mScrollState != OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
@@ -1937,9 +1948,25 @@ public class NumberPicker extends LinearLayout {
          */
         String text = (mDisplayedValues == null) ? formatNumber(mValue)
                 : mDisplayedValues[mValue - mMinValue];
-        if (!TextUtils.isEmpty(text) && !text.equals(mInputText.getText().toString())) {
-            mInputText.setText(text);
-            return true;
+        if (!TextUtils.isEmpty(text)) {
+            CharSequence beforeText = mInputText.getText();
+            if (!text.equals(beforeText.toString())) {
+                mInputText.setText(text);
+                if (mAccessibilityNodeProvider != null) {
+                    AccessibilityEvent event = AccessibilityEvent.obtain(
+                            AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED);
+                    mInputText.onInitializeAccessibilityEvent(event);
+                    mInputText.onPopulateAccessibilityEvent(event);
+                    event.setFromIndex(0);
+                    event.setRemovedCount(beforeText.length());
+                    event.setAddedCount(text.length());
+                    event.setBeforeText(beforeText);
+                    event.setSource(NumberPicker.this,
+                            AccessibilityNodeProviderImpl.VIRTUAL_VIEW_ID_INPUT);
+                    requestSendAccessibilityEvent(NumberPicker.this, event);
+                }
+                return true;
+            }
         }
 
         return false;