1/*
2 * Copyright 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package androidx.recyclerview.widget;
18
19import android.os.Bundle;
20import android.view.View;
21import android.view.accessibility.AccessibilityEvent;
22
23import androidx.annotation.NonNull;
24import androidx.core.view.AccessibilityDelegateCompat;
25import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;
26
27/**
28 * The AccessibilityDelegate used by RecyclerView.
29 * <p>
30 * This class handles basic accessibility actions and delegates them to LayoutManager.
31 */
32public class RecyclerViewAccessibilityDelegate extends AccessibilityDelegateCompat {
33    final RecyclerView mRecyclerView;
34    final AccessibilityDelegateCompat mItemDelegate;
35
36
37    public RecyclerViewAccessibilityDelegate(@NonNull RecyclerView recyclerView) {
38        mRecyclerView = recyclerView;
39        mItemDelegate = new ItemDelegate(this);
40    }
41
42    boolean shouldIgnore() {
43        return mRecyclerView.hasPendingAdapterUpdates();
44    }
45
46    @Override
47    public boolean performAccessibilityAction(View host, int action, Bundle args) {
48        if (super.performAccessibilityAction(host, action, args)) {
49            return true;
50        }
51        if (!shouldIgnore() && mRecyclerView.getLayoutManager() != null) {
52            return mRecyclerView.getLayoutManager().performAccessibilityAction(action, args);
53        }
54
55        return false;
56    }
57
58    @Override
59    public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) {
60        super.onInitializeAccessibilityNodeInfo(host, info);
61        info.setClassName(RecyclerView.class.getName());
62        if (!shouldIgnore() && mRecyclerView.getLayoutManager() != null) {
63            mRecyclerView.getLayoutManager().onInitializeAccessibilityNodeInfo(info);
64        }
65    }
66
67    @Override
68    public void onInitializeAccessibilityEvent(View host, AccessibilityEvent event) {
69        super.onInitializeAccessibilityEvent(host, event);
70        event.setClassName(RecyclerView.class.getName());
71        if (host instanceof RecyclerView && !shouldIgnore()) {
72            RecyclerView rv = (RecyclerView) host;
73            if (rv.getLayoutManager() != null) {
74                rv.getLayoutManager().onInitializeAccessibilityEvent(event);
75            }
76        }
77    }
78
79    /**
80     * Gets the AccessibilityDelegate for an individual item in the RecyclerView.
81     * A basic item delegate is provided by default, but you can override this
82     * method to provide a custom per-item delegate.
83     */
84    @NonNull
85    public AccessibilityDelegateCompat getItemDelegate() {
86        return mItemDelegate;
87    }
88
89    /**
90     * The default implementation of accessibility delegate for the individual items of the
91     * RecyclerView.
92     * <p>
93     * If you are overriding {@code RecyclerViewAccessibilityDelegate#getItemDelegate()} but still
94     * want to keep some default behavior, you can create an instance of this class and delegate to
95     * the parent as necessary.
96     */
97    public static class ItemDelegate extends AccessibilityDelegateCompat {
98        final RecyclerViewAccessibilityDelegate mRecyclerViewDelegate;
99
100        /**
101         * Creates an item delegate for the given {@code RecyclerViewAccessibilityDelegate}.
102         *
103         * @param recyclerViewDelegate The parent RecyclerView's accessibility delegate.
104         */
105        public ItemDelegate(@NonNull RecyclerViewAccessibilityDelegate recyclerViewDelegate) {
106            mRecyclerViewDelegate = recyclerViewDelegate;
107        }
108
109        @Override
110        public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) {
111            super.onInitializeAccessibilityNodeInfo(host, info);
112            if (!mRecyclerViewDelegate.shouldIgnore()
113                    && mRecyclerViewDelegate.mRecyclerView.getLayoutManager() != null) {
114                mRecyclerViewDelegate.mRecyclerView.getLayoutManager()
115                        .onInitializeAccessibilityNodeInfoForItem(host, info);
116            }
117        }
118
119        @Override
120        public boolean performAccessibilityAction(View host, int action, Bundle args) {
121            if (super.performAccessibilityAction(host, action, args)) {
122                return true;
123            }
124            if (!mRecyclerViewDelegate.shouldIgnore()
125                    && mRecyclerViewDelegate.mRecyclerView.getLayoutManager() != null) {
126                return mRecyclerViewDelegate.mRecyclerView.getLayoutManager()
127                        .performAccessibilityActionForItem(host, action, args);
128            }
129            return false;
130        }
131    }
132}
133
134