diff --git a/ci/licenses_golden/licenses_flutter b/ci/licenses_golden/licenses_flutter index 63b2ac899e260..7cf25b3228d94 100644 --- a/ci/licenses_golden/licenses_flutter +++ b/ci/licenses_golden/licenses_flutter @@ -445,6 +445,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/platform/SingleV FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/platform/VirtualDisplayController.java FILE: ../../../flutter/shell/platform/android/io/flutter/util/PathUtils.java FILE: ../../../flutter/shell/platform/android/io/flutter/util/Preconditions.java +FILE: ../../../flutter/shell/platform/android/io/flutter/util/Predicate.java FILE: ../../../flutter/shell/platform/android/io/flutter/view/AccessibilityBridge.java FILE: ../../../flutter/shell/platform/android/io/flutter/view/FlutterCallbackInformation.java FILE: ../../../flutter/shell/platform/android/io/flutter/view/FlutterMain.java diff --git a/shell/platform/android/BUILD.gn b/shell/platform/android/BUILD.gn index aad27b2f9dd37..b9df763dbb7aa 100644 --- a/shell/platform/android/BUILD.gn +++ b/shell/platform/android/BUILD.gn @@ -131,6 +131,7 @@ java_library("flutter_shell_java") { "io/flutter/plugin/platform/VirtualDisplayController.java", "io/flutter/util/PathUtils.java", "io/flutter/util/Preconditions.java", + "io/flutter/util/Predicate.java", "io/flutter/view/AccessibilityBridge.java", "io/flutter/view/FlutterCallbackInformation.java", "io/flutter/view/FlutterMain.java", diff --git a/shell/platform/android/io/flutter/util/Predicate.java b/shell/platform/android/io/flutter/util/Predicate.java new file mode 100644 index 0000000000000..96c6c1d1cd478 --- /dev/null +++ b/shell/platform/android/io/flutter/util/Predicate.java @@ -0,0 +1,11 @@ +// Copyright 2013 The Flutter Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +package io.flutter.util; + +// TODO(dnfield): remove this if/when we can use appcompat to support it. +// java.util.function.Predicate isn't available until API24 +public interface Predicate { + public abstract boolean test(T t); +} \ No newline at end of file diff --git a/shell/platform/android/io/flutter/view/AccessibilityBridge.java b/shell/platform/android/io/flutter/view/AccessibilityBridge.java index 4fc808e9eea5f..ab65e17acae37 100644 --- a/shell/platform/android/io/flutter/view/AccessibilityBridge.java +++ b/shell/platform/android/io/flutter/view/AccessibilityBridge.java @@ -16,6 +16,7 @@ import android.view.accessibility.AccessibilityNodeProvider; import io.flutter.plugin.common.BasicMessageChannel; import io.flutter.plugin.common.StandardMessageCodec; +import io.flutter.util.Predicate; import java.nio.ByteBuffer; import java.util.*; @@ -125,6 +126,36 @@ void setAccessibilityEnabled(boolean accessibilityEnabled) { } } + private boolean shouldSetCollectionInfo(SemanticsObject object) { + // TODO(dnfield): make these lambdas when Java 1.8 support lands. + Predicate parentMatcher = new Predicate() { + @Override + public boolean test(SemanticsObject o) { + return o == mA11yFocusedObject; + } + }; + + Predicate flagMatcher = new Predicate() { + @Override + public boolean test(SemanticsObject o) { + return o.hasFlag(Flag.HAS_IMPLICIT_SCROLLING); + } + }; + + // TalkBack expects a number of rows and/or columns greater than 0 to announce + // in list and out of list. For an infinite or growing list, you have to + // specify something > 0 to get "in list" announcements. + // TalkBack will also only track one list at a time, so we only want to set this + // for a list that contians the current a11y focused object - otherwise, if there + // are two lists or nested lists, we may end up with announcements for only the last + // one that is currently availalbe in the semantics tree. However, we also want + // to set it if we're exiting a list to a non-list, so that we can get the "out of list" + // announcement when A11y focus moves out of a list and not into another list. + return object.scrollChildren > 0 + && (hasSemanticsObjectAncestor(mA11yFocusedObject, parentMatcher) + || !hasSemanticsObjectAncestor(mA11yFocusedObject, flagMatcher)); + } + @Override @SuppressWarnings("deprecation") public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId) { @@ -266,14 +297,29 @@ public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId) { if (object.hasAction(Action.SCROLL_LEFT) || object.hasAction(Action.SCROLL_UP) || object.hasAction(Action.SCROLL_RIGHT) || object.hasAction(Action.SCROLL_DOWN)) { result.setScrollable(true); + // This tells Android's a11y to send scroll events when reaching the end of // the visible viewport of a scrollable, unless the node itself does not // allow implicit scrolling - then we leave the className as view.View. + // + // We should prefer setCollectionInfo to the class names, as this way we get "In List" + // and "Out of list" announcements. But we don't always know the counts, so we + // can fallback to the generic scroll view class names. + // TODO(dnfield): We should add semantics properties for rows and columns in 2 dimensional lists, e.g. + // GridView. Right now, we're only supporting ListViews and only if they have scroll children. if (object.hasFlag(Flag.HAS_IMPLICIT_SCROLLING)) { if (object.hasAction(Action.SCROLL_LEFT) || object.hasAction(Action.SCROLL_RIGHT)) { - result.setClassName("android.widget.HorizontalScrollView"); + if (shouldSetCollectionInfo(object)) { + result.setCollectionInfo(AccessibilityNodeInfo.CollectionInfo.obtain(0, object.scrollChildren, false)); + } else { + result.setClassName("android.widget.HorizontalScrollView"); + } } else { - result.setClassName("android.widget.ScrollView"); + if (shouldSetCollectionInfo(object)) { + result.setCollectionInfo(AccessibilityNodeInfo.CollectionInfo.obtain(object.scrollChildren, 0, false)); + } else { + result.setClassName("android.widget.ScrollView"); + } } } // TODO(ianh): Once we're on SDK v23+, call addAction to @@ -960,6 +1006,11 @@ boolean isStandardAction() { /// Value is derived from ACTION_TYPE_MASK in AccessibilityNodeInfo.java static int firstResourceId = 267386881; + + static boolean hasSemanticsObjectAncestor(SemanticsObject target, Predicate tester) { + return target != null && target.getAncestor(tester) != null; + } + private class SemanticsObject { SemanticsObject() {} @@ -1012,6 +1063,17 @@ private class SemanticsObject { private float[] globalTransform; private Rect globalRect; + SemanticsObject getAncestor(Predicate tester) { + SemanticsObject nextAncestor = parent; + while (nextAncestor != null) { + if (tester.test(nextAncestor)) { + return nextAncestor; + } + nextAncestor = nextAncestor.parent; + } + return null; + } + boolean hasAction(Action action) { return (actions & action.value) != 0; }