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1/*
2 * Copyright (C) 2012 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 android.support.v4.view.accessibility;
18
19import android.os.Build;
20import android.os.Bundle;
21import android.support.annotation.Nullable;
22import android.view.View;
23
24import java.util.ArrayList;
25import java.util.List;
26
27/**
28 * Helper for accessing {@link android.view.accessibility.AccessibilityNodeProvider}
29 * introduced after API level 4 in a backwards compatible fashion.
30 */
31public class AccessibilityNodeProviderCompat {
32
33    interface AccessibilityNodeProviderImpl {
34        Object newAccessibilityNodeProviderBridge(AccessibilityNodeProviderCompat compat);
35    }
36
37    static class AccessibilityNodeProviderStubImpl implements AccessibilityNodeProviderImpl {
38        @Override
39        public Object newAccessibilityNodeProviderBridge(AccessibilityNodeProviderCompat compat) {
40            return null;
41        }
42    }
43
44    private static class AccessibilityNodeProviderJellyBeanImpl
45            extends AccessibilityNodeProviderStubImpl {
46        @Override
47        public Object newAccessibilityNodeProviderBridge(
48                final AccessibilityNodeProviderCompat compat) {
49            return AccessibilityNodeProviderCompatJellyBean.newAccessibilityNodeProviderBridge(
50                    new AccessibilityNodeProviderCompatJellyBean.AccessibilityNodeInfoBridge() {
51                        @Override
52                        public boolean performAction(int virtualViewId, int action,
53                                Bundle arguments) {
54                            return compat.performAction(virtualViewId, action, arguments);
55                        }
56
57                        @Override
58                        public List<Object> findAccessibilityNodeInfosByText(
59                                            String text, int virtualViewId) {
60                            final List<AccessibilityNodeInfoCompat> compatInfos =
61                                compat.findAccessibilityNodeInfosByText(text, virtualViewId);
62                            if (compatInfos == null) {
63                                return null;
64                            } else {
65                                final List<Object> infos = new ArrayList<>();
66                                final int infoCount = compatInfos.size();
67                                for (int i = 0; i < infoCount; i++) {
68                                    AccessibilityNodeInfoCompat infoCompat = compatInfos.get(i);
69                                    infos.add(infoCompat.getInfo());
70                                }
71                                return infos;
72                            }
73                        }
74
75                        @Override
76                        public Object createAccessibilityNodeInfo(
77                                int virtualViewId) {
78                            final AccessibilityNodeInfoCompat compatInfo =
79                                    compat.createAccessibilityNodeInfo(virtualViewId);
80                            if (compatInfo == null) {
81                                return null;
82                            } else {
83                                return compatInfo.getInfo();
84                            }
85                        }
86                    });
87        }
88    }
89
90    private static class AccessibilityNodeProviderKitKatImpl
91            extends AccessibilityNodeProviderStubImpl {
92        @Override
93        public Object newAccessibilityNodeProviderBridge(
94                final AccessibilityNodeProviderCompat compat) {
95            return AccessibilityNodeProviderCompatKitKat.newAccessibilityNodeProviderBridge(
96                    new AccessibilityNodeProviderCompatKitKat.AccessibilityNodeInfoBridge() {
97                        @Override
98                        public boolean performAction(
99                                int virtualViewId, int action, Bundle arguments) {
100                            return compat.performAction(virtualViewId, action, arguments);
101                        }
102
103                        @Override
104                        public List<Object> findAccessibilityNodeInfosByText(
105                                String text, int virtualViewId) {
106                            final List<AccessibilityNodeInfoCompat> compatInfos =
107                                    compat.findAccessibilityNodeInfosByText(text, virtualViewId);
108                            if (compatInfos == null) {
109                                return null;
110                            } else {
111                                final List<Object> infos = new ArrayList<>();
112                                final int infoCount = compatInfos.size();
113                                for (int i = 0; i < infoCount; i++) {
114                                    AccessibilityNodeInfoCompat infoCompat = compatInfos.get(i);
115                                    infos.add(infoCompat.getInfo());
116                                }
117                                return infos;
118                            }
119                        }
120
121                        @Override
122                        public Object createAccessibilityNodeInfo(int virtualViewId) {
123                            final AccessibilityNodeInfoCompat compatInfo =
124                                    compat.createAccessibilityNodeInfo(virtualViewId);
125                            if (compatInfo == null) {
126                                return null;
127                            } else {
128                                return compatInfo.getInfo();
129                            }
130                        }
131
132                        @Override
133                        public Object findFocus(int focus) {
134                            final AccessibilityNodeInfoCompat compatInfo = compat.findFocus(focus);
135                            if (compatInfo == null) {
136                                return null;
137                            } else {
138                                return compatInfo.getInfo();
139                            }
140                        }
141                    });
142        }
143    }
144
145    private static final AccessibilityNodeProviderImpl IMPL;
146
147    private final Object mProvider;
148
149    static {
150        if (Build.VERSION.SDK_INT >= 19) { // KitKat
151            IMPL = new AccessibilityNodeProviderKitKatImpl();
152        } else if (Build.VERSION.SDK_INT >= 16) { // JellyBean
153            IMPL = new AccessibilityNodeProviderJellyBeanImpl();
154        } else {
155            IMPL = new AccessibilityNodeProviderStubImpl();
156        }
157    }
158
159    /**
160     * Creates a new instance.
161     */
162    public AccessibilityNodeProviderCompat() {
163        mProvider = IMPL.newAccessibilityNodeProviderBridge(this);
164    }
165
166    /**
167     * Creates a new instance wrapping an
168     * {@link android.view.accessibility.AccessibilityNodeProvider}.
169     *
170     * @param provider The provider.
171     */
172    public AccessibilityNodeProviderCompat(Object provider) {
173        mProvider = provider;
174    }
175
176    /**
177     * @return The wrapped {@link android.view.accessibility.AccessibilityNodeProvider}.
178     */
179    public Object getProvider() {
180        return mProvider;
181    }
182
183    /**
184     * Returns an {@link AccessibilityNodeInfoCompat} representing a virtual view,
185     * i.e. a descendant of the host View, with the given <code>virtualViewId</code>
186     * or the host View itself if <code>virtualViewId</code> equals to {@link View#NO_ID}.
187     * <p>
188     * A virtual descendant is an imaginary View that is reported as a part of the view
189     * hierarchy for accessibility purposes. This enables custom views that draw complex
190     * content to report them selves as a tree of virtual views, thus conveying their
191     * logical structure.
192     * </p>
193     * <p>
194     * The implementer is responsible for obtaining an accessibility node info from the
195     * pool of reusable instances and setting the desired properties of the node info
196     * before returning it.
197     * </p>
198     *
199     * @param virtualViewId A client defined virtual view id.
200     * @return A populated {@link AccessibilityNodeInfoCompat} for a virtual descendant
201     *     or the host View.
202     *
203     * @see AccessibilityNodeInfoCompat
204     */
205    @Nullable
206    public AccessibilityNodeInfoCompat createAccessibilityNodeInfo(int virtualViewId) {
207        return null;
208    }
209
210    /**
211     * Performs an accessibility action on a virtual view, i.e. a descendant of the
212     * host View, with the given <code>virtualViewId</code> or the host View itself
213     * if <code>virtualViewId</code> equals to {@link View#NO_ID}.
214     *
215     * @param virtualViewId A client defined virtual view id.
216     * @param action The action to perform.
217     * @param arguments Optional arguments.
218     * @return True if the action was performed.
219     *
220     * @see #createAccessibilityNodeInfo(int)
221     * @see AccessibilityNodeInfoCompat
222     */
223    public boolean performAction(int virtualViewId, int action, Bundle arguments) {
224        return false;
225    }
226
227    /**
228     * Finds {@link AccessibilityNodeInfoCompat}s by text. The match is case insensitive
229     * containment. The search is relative to the virtual view, i.e. a descendant of the
230     * host View, with the given <code>virtualViewId</code> or the host View itself
231     * <code>virtualViewId</code> equals to {@link View#NO_ID}.
232     *
233     * @param virtualViewId A client defined virtual view id which defined
234     *     the root of the tree in which to perform the search.
235     * @param text The searched text.
236     * @return A list of node info.
237     *
238     * @see #createAccessibilityNodeInfo(int)
239     * @see AccessibilityNodeInfoCompat
240     */
241    @Nullable
242    public List<AccessibilityNodeInfoCompat> findAccessibilityNodeInfosByText(String text,
243            int virtualViewId) {
244        return null;
245    }
246
247    /**
248     * Find the virtual view, i.e. a descendant of the host View, that has the
249     * specified focus type.
250     *
251     * @param focus The focus to find. One of
252     *            {@link AccessibilityNodeInfoCompat#FOCUS_INPUT} or
253     *            {@link AccessibilityNodeInfoCompat#FOCUS_ACCESSIBILITY}.
254     * @return The node info of the focused view or null.
255     * @see AccessibilityNodeInfoCompat#FOCUS_INPUT
256     * @see AccessibilityNodeInfoCompat#FOCUS_ACCESSIBILITY
257     */
258    @Nullable
259    public AccessibilityNodeInfoCompat findFocus(int focus) {
260        return null;
261    }
262}
263