Add API for nested pre-processing of a11y events; fix ResolverDrawerLayout
Add API for handling nested pre-processing of accessibility events
similar to nested pre-scroll or pre-fling. This allows custom views to
delegate a nested scroll to a parent via the accessibility system.
Use this functionality to allow opening the ResolverDrawerLayout via
accessibility commands.
Bug 18827274
Change-Id: Icd5a502605b78a861bb03e7b11923841a72eb9ab
diff --git a/api/current.txt b/api/current.txt
index 24501f3..96c50a2 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -33332,6 +33332,7 @@
method public boolean dispatchKeyShortcutEvent(android.view.KeyEvent);
method public boolean dispatchNestedFling(float, float, boolean);
method public boolean dispatchNestedPreFling(float, float);
+ method public boolean dispatchNestedPrePerformAccessibilityAction(int, android.os.Bundle);
method public boolean dispatchNestedPreScroll(int, int, int[], int[]);
method public boolean dispatchNestedScroll(int, int, int, int, int[]);
method public boolean dispatchPopulateAccessibilityEvent(android.view.accessibility.AccessibilityEvent);
@@ -34144,6 +34145,7 @@
method protected abstract void onLayout(boolean, int, int, int, int);
method public boolean onNestedFling(android.view.View, float, float, boolean);
method public boolean onNestedPreFling(android.view.View, float, float);
+ method public boolean onNestedPrePerformAccessibilityAction(android.view.View, int, android.os.Bundle);
method public void onNestedPreScroll(android.view.View, int, int, int[]);
method public void onNestedScroll(android.view.View, int, int, int, int);
method public void onNestedScrollAccepted(android.view.View, android.view.View, int);
@@ -34292,6 +34294,7 @@
method public abstract void notifySubtreeAccessibilityStateChanged(android.view.View, android.view.View, int);
method public abstract boolean onNestedFling(android.view.View, float, float, boolean);
method public abstract boolean onNestedPreFling(android.view.View, float, float);
+ method public abstract boolean onNestedPrePerformAccessibilityAction(android.view.View, int, android.os.Bundle);
method public abstract void onNestedPreScroll(android.view.View, int, int, int[]);
method public abstract void onNestedScroll(android.view.View, int, int, int, int);
method public abstract void onNestedScrollAccepted(android.view.View, android.view.View, int);
diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index 23792be..6a36c26 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -8159,6 +8159,34 @@
}
/**
+ * Report an accessibility action to this view's parents for delegated processing.
+ *
+ * <p>Implementations of {@link #performAccessibilityAction(int, Bundle)} may internally
+ * call this method to delegate an accessibility action to a supporting parent. If the parent
+ * returns true from its
+ * {@link ViewParent#onNestedPrePerformAccessibilityAction(View, int, android.os.Bundle)}
+ * method this method will return true to signify that the action was consumed.</p>
+ *
+ * <p>This method is useful for implementing nested scrolling child views. If
+ * {@link #isNestedScrollingEnabled()} returns true and the action is a scrolling action
+ * a custom view implementation may invoke this method to allow a parent to consume the
+ * scroll first. If this method returns true the custom view should skip its own scrolling
+ * behavior.</p>
+ *
+ * @param action Accessibility action to delegate
+ * @param arguments Optional action arguments
+ * @return true if the action was consumed by a parent
+ */
+ public boolean dispatchNestedPrePerformAccessibilityAction(int action, Bundle arguments) {
+ for (ViewParent p = getParent(); p != null; p = p.getParent()) {
+ if (p.onNestedPrePerformAccessibilityAction(this, action, arguments)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ /**
* Performs the specified accessibility action on the view. For
* possible accessibility actions look at {@link AccessibilityNodeInfo}.
* <p>
@@ -8168,6 +8196,11 @@
* is responsible for handling this call.
* </p>
*
+ * <p>The default implementation will delegate
+ * {@link AccessibilityNodeInfo#ACTION_SCROLL_BACKWARD} and
+ * {@link AccessibilityNodeInfo#ACTION_SCROLL_FORWARD} to nested scrolling parents if
+ * {@link #isNestedScrollingEnabled() nested scrolling is enabled} on this view.</p>
+ *
* @param action The action to perform.
* @param arguments Optional action arguments.
* @return Whether the action was performed.
@@ -8188,6 +8221,14 @@
* @hide Until we've refactored all accessibility delegation methods.
*/
public boolean performAccessibilityActionInternal(int action, Bundle arguments) {
+ if (isNestedScrollingEnabled()
+ && (action == AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD
+ || action == AccessibilityNodeInfo.ACTION_SCROLL_FORWARD)) {
+ if (dispatchNestedPrePerformAccessibilityAction(action, arguments)) {
+ return true;
+ }
+ }
+
switch (action) {
case AccessibilityNodeInfo.ACTION_CLICK: {
if (isClickable()) {
diff --git a/core/java/android/view/ViewGroup.java b/core/java/android/view/ViewGroup.java
index 22c5185..6678ff2 100644
--- a/core/java/android/view/ViewGroup.java
+++ b/core/java/android/view/ViewGroup.java
@@ -32,6 +32,7 @@
import android.graphics.RectF;
import android.graphics.Region;
import android.os.Build;
+import android.os.Bundle;
import android.os.Parcelable;
import android.os.SystemClock;
import android.util.AttributeSet;
@@ -2923,6 +2924,22 @@
/**
* {@inheritDoc}
+ *
+ * <p>Subclasses should always call <code>super.onNestedPrePerformAccessibilityAction</code></p>
+ *
+ * @param target The target view dispatching this action
+ * @param action Action being performed; see
+ * {@link android.view.accessibility.AccessibilityNodeInfo}
+ * @param args Optional action arguments
+ * @return false by default. Subclasses should return true if they handle the event.
+ */
+ @Override
+ public boolean onNestedPrePerformAccessibilityAction(View target, int action, Bundle args) {
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
*/
@Override
void dispatchDetachedFromWindow() {
diff --git a/core/java/android/view/ViewParent.java b/core/java/android/view/ViewParent.java
index 87a37f4..035871d 100644
--- a/core/java/android/view/ViewParent.java
+++ b/core/java/android/view/ViewParent.java
@@ -17,6 +17,7 @@
package android.view;
import android.graphics.Rect;
+import android.os.Bundle;
import android.view.accessibility.AccessibilityEvent;
/**
@@ -551,4 +552,23 @@
* @return true if this parent consumed the fling ahead of the target view
*/
public boolean onNestedPreFling(View target, float velocityX, float velocityY);
+
+ /**
+ * React to an accessibility action delegated by a target descendant view before the target
+ * processes it.
+ *
+ * <p>This method may be called by a target descendant view if the target wishes to give
+ * a view in its parent chain a chance to react to the event before normal processing occurs.
+ * Most commonly this will be a scroll event such as
+ * {@link android.view.accessibility.AccessibilityNodeInfo#ACTION_SCROLL_FORWARD}.
+ * A ViewParent that supports acting as a nested scrolling parent should override this
+ * method and act accordingly to implement scrolling via accesibility systems.</p>
+ *
+ * @param target The target view dispatching this action
+ * @param action Action being performed; see
+ * {@link android.view.accessibility.AccessibilityNodeInfo}
+ * @param arguments Optional action arguments
+ * @return true if the action was consumed by this ViewParent
+ */
+ public boolean onNestedPrePerformAccessibilityAction(View target, int action, Bundle arguments);
}
diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 34c27d7..25dd9c7 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -6413,6 +6413,11 @@
return false;
}
+ @Override
+ public boolean onNestedPrePerformAccessibilityAction(View target, int action, Bundle args) {
+ return false;
+ }
+
void changeCanvasOpacity(boolean opaque) {
Log.d(TAG, "changeCanvasOpacity: opaque=" + opaque);
if (mAttachInfo.mHardwareRenderer != null) {
diff --git a/core/java/com/android/internal/widget/ResolverDrawerLayout.java b/core/java/com/android/internal/widget/ResolverDrawerLayout.java
index ed7af2f..4e48454 100644
--- a/core/java/com/android/internal/widget/ResolverDrawerLayout.java
+++ b/core/java/com/android/internal/widget/ResolverDrawerLayout.java
@@ -20,6 +20,7 @@
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Rect;
+import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
@@ -31,6 +32,8 @@
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.ViewTreeObserver;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityNodeInfo;
import android.view.animation.AnimationUtils;
import android.widget.AbsListView;
import android.widget.OverScroller;
@@ -367,8 +370,14 @@
child.offsetTopAndBottom((int) dy);
}
}
+ final boolean isCollapsedOld = mCollapseOffset != 0;
mCollapseOffset = newPos;
mTopOffset += dy;
+ final boolean isCollapsedNew = newPos != 0;
+ if (isCollapsedOld != isCollapsedNew) {
+ notifyViewAccessibilityStateChangedIfNeeded(
+ AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED);
+ }
postInvalidateOnAnimation();
return dy;
}
@@ -571,6 +580,50 @@
}
@Override
+ public boolean onNestedPrePerformAccessibilityAction(View target, int action, Bundle args) {
+ if (super.onNestedPrePerformAccessibilityAction(target, action, args)) {
+ return true;
+ }
+
+ if (action == AccessibilityNodeInfo.ACTION_SCROLL_FORWARD && mCollapseOffset != 0) {
+ smoothScrollTo(0, 0);
+ return true;
+ }
+ return false;
+ }
+
+ @Override
+ public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
+ super.onInitializeAccessibilityEvent(event);
+ event.setClassName(ResolverDrawerLayout.class.getName());
+ }
+
+ @Override
+ public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+ super.onInitializeAccessibilityNodeInfo(info);
+ info.setClassName(ResolverDrawerLayout.class.getName());
+ if (isEnabled()) {
+ if (mCollapseOffset != 0) {
+ info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD);
+ info.setScrollable(true);
+ }
+ }
+ }
+
+ @Override
+ public boolean performAccessibilityAction(int action, Bundle arguments) {
+ if (super.performAccessibilityAction(action, arguments)) {
+ return true;
+ }
+
+ if (action == AccessibilityNodeInfo.ACTION_SCROLL_FORWARD && mCollapseOffset != 0) {
+ smoothScrollTo(0, 0);
+ return true;
+ }
+ return false;
+ }
+
+ @Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
final int sourceWidth = MeasureSpec.getSize(widthMeasureSpec);
int widthSize = sourceWidth;
@@ -615,7 +668,13 @@
mUncollapsibleHeight = heightUsed - mCollapsibleHeight;
if (isLaidOut()) {
+ final boolean isCollapsedOld = mCollapseOffset != 0;
mCollapseOffset = Math.min(mCollapseOffset, mCollapsibleHeight);
+ final boolean isCollapsedNew = mCollapseOffset != 0;
+ if (isCollapsedOld != isCollapsedNew) {
+ notifyViewAccessibilityStateChangedIfNeeded(
+ AccessibilityEvent.CONTENT_CHANGE_TYPE_UNDEFINED);
+ }
} else {
// Start out collapsed at first unless we restored state for otherwise
mCollapseOffset = mOpenOnLayout ? 0 : mCollapsibleHeight;