1/*
2 * Copyright (C) 2011 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;
18
19import android.os.Build;
20import android.os.Bundle;
21import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
22import android.support.v4.view.accessibility.AccessibilityNodeProviderCompat;
23import android.view.View;
24import android.view.ViewGroup;
25import android.view.accessibility.AccessibilityEvent;
26
27/**
28 * Helper for accessing {@link View.AccessibilityDelegate} introduced after
29 * API level 4 in a backwards compatible fashion.
30 * <p>
31 * <strong>Note:</strong> On platform versions prior to
32 * {@link android.os.Build.VERSION_CODES#M API 23}, delegate methods on
33 * views in the {@code android.widget.*} package are called <i>before</i>
34 * host methods. This prevents certain properties such as class name from
35 * being modified by overriding
36 * {@link AccessibilityDelegateCompat#onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfoCompat)},
37 * as any changes will be overwritten by the host class.
38 * <p>
39 * Starting in {@link android.os.Build.VERSION_CODES#M API 23}, delegate
40 * methods are called <i>after</i> host methods, which all properties to be
41 * modified without being overwritten by the host class.
42 */
43public class AccessibilityDelegateCompat {
44
45    static interface AccessibilityDelegateImpl {
46        public Object newAccessiblityDelegateDefaultImpl();
47        public Object newAccessiblityDelegateBridge(AccessibilityDelegateCompat listener);
48        public boolean dispatchPopulateAccessibilityEvent(Object delegate, View host,
49                AccessibilityEvent event);
50        public void onInitializeAccessibilityEvent(Object delegate, View host,
51                AccessibilityEvent event);
52        public void onInitializeAccessibilityNodeInfo(Object delegate, View host,
53                AccessibilityNodeInfoCompat info);
54        public void onPopulateAccessibilityEvent(Object delegate, View host,
55                AccessibilityEvent event);
56        public boolean onRequestSendAccessibilityEvent(Object delegate, ViewGroup host, View child,
57                AccessibilityEvent event);
58        public void sendAccessibilityEvent(Object delegate, View host, int eventType);
59        public void sendAccessibilityEventUnchecked(Object delegate, View host,
60                AccessibilityEvent event);
61        public AccessibilityNodeProviderCompat getAccessibilityNodeProvider(Object delegate,
62                View host);
63        public boolean performAccessibilityAction(Object delegate, View host, int action,
64                Bundle args);
65    }
66
67    static class AccessibilityDelegateStubImpl implements AccessibilityDelegateImpl {
68        public Object newAccessiblityDelegateDefaultImpl() {
69            return null;
70        }
71
72        @Override
73        public Object newAccessiblityDelegateBridge(AccessibilityDelegateCompat listener) {
74            return null;
75        }
76
77        @Override
78        public boolean dispatchPopulateAccessibilityEvent(Object delegate, View host,
79                AccessibilityEvent event) {
80            return false;
81        }
82
83        @Override
84        public void onInitializeAccessibilityEvent(Object delegate, View host,
85                AccessibilityEvent event) {
86
87        }
88
89        @Override
90        public void onInitializeAccessibilityNodeInfo(Object delegate, View host,
91                AccessibilityNodeInfoCompat info) {
92
93        }
94
95        @Override
96        public void onPopulateAccessibilityEvent(Object delegate, View host,
97                AccessibilityEvent event) {
98
99        }
100
101        @Override
102        public boolean onRequestSendAccessibilityEvent(Object delegate, ViewGroup host, View child,
103                AccessibilityEvent event) {
104            return true;
105        }
106
107        @Override
108        public void sendAccessibilityEvent(Object delegate, View host, int eventType) {
109
110        }
111
112        @Override
113        public void sendAccessibilityEventUnchecked(Object delegate, View host,
114                AccessibilityEvent event) {
115
116        }
117
118        @Override
119        public AccessibilityNodeProviderCompat getAccessibilityNodeProvider(Object delegate,
120                View host) {
121            return null;
122        }
123
124        @Override
125        public boolean performAccessibilityAction(Object delegate, View host, int action,
126                Bundle args) {
127            return false;
128        }
129    }
130
131    static class AccessibilityDelegateIcsImpl extends AccessibilityDelegateStubImpl {
132        @Override
133        public Object newAccessiblityDelegateDefaultImpl() {
134            return AccessibilityDelegateCompatIcs.newAccessibilityDelegateDefaultImpl();
135        }
136
137        @Override
138        public Object newAccessiblityDelegateBridge(final AccessibilityDelegateCompat compat) {
139            return AccessibilityDelegateCompatIcs.newAccessibilityDelegateBridge(
140                    new AccessibilityDelegateCompatIcs.AccessibilityDelegateBridge() {
141                @Override
142                public boolean dispatchPopulateAccessibilityEvent(View host,
143                        AccessibilityEvent event) {
144                    return compat.dispatchPopulateAccessibilityEvent(host, event);
145                }
146
147                @Override
148                public void onInitializeAccessibilityEvent(View host, AccessibilityEvent event) {
149                    compat.onInitializeAccessibilityEvent(host, event);
150                }
151
152                @Override
153                public void onInitializeAccessibilityNodeInfo(View host, Object info) {
154                    compat.onInitializeAccessibilityNodeInfo(host,
155                            new AccessibilityNodeInfoCompat(info));
156                }
157
158                @Override
159                public void onPopulateAccessibilityEvent(View host, AccessibilityEvent event) {
160                    compat.onPopulateAccessibilityEvent(host, event);
161                }
162
163                @Override
164                public boolean onRequestSendAccessibilityEvent(ViewGroup host, View child,
165                        AccessibilityEvent event) {
166                    return compat.onRequestSendAccessibilityEvent(host, child, event);
167                }
168
169                @Override
170                public void sendAccessibilityEvent(View host, int eventType) {
171                    compat.sendAccessibilityEvent(host, eventType);
172                }
173
174                @Override
175                public void sendAccessibilityEventUnchecked(View host, AccessibilityEvent event) {
176                    compat.sendAccessibilityEventUnchecked(host, event);
177                }
178            });
179        }
180
181        @Override
182        public boolean dispatchPopulateAccessibilityEvent(Object delegate, View host,
183                AccessibilityEvent event) {
184            return AccessibilityDelegateCompatIcs.dispatchPopulateAccessibilityEvent(delegate,
185                    host, event);
186        }
187
188        @Override
189        public void onInitializeAccessibilityEvent(Object delegate, View host,
190                AccessibilityEvent event) {
191            AccessibilityDelegateCompatIcs.onInitializeAccessibilityEvent(delegate, host, event);
192        }
193
194        @Override
195        public void onInitializeAccessibilityNodeInfo(Object delegate, View host,
196                AccessibilityNodeInfoCompat info) {
197            AccessibilityDelegateCompatIcs.onInitializeAccessibilityNodeInfo(delegate, host,
198                    info.getInfo());
199        }
200
201        @Override
202        public void onPopulateAccessibilityEvent(Object delegate, View host,
203                AccessibilityEvent event) {
204            AccessibilityDelegateCompatIcs.onPopulateAccessibilityEvent(delegate, host, event);
205        }
206
207        @Override
208        public boolean onRequestSendAccessibilityEvent(Object delegate, ViewGroup host, View child,
209                AccessibilityEvent event) {
210            return AccessibilityDelegateCompatIcs.onRequestSendAccessibilityEvent(delegate, host,
211                    child, event);
212        }
213
214        @Override
215        public void sendAccessibilityEvent(Object delegate, View host, int eventType) {
216            AccessibilityDelegateCompatIcs.sendAccessibilityEvent(delegate, host, eventType);
217        }
218
219        @Override
220        public void sendAccessibilityEventUnchecked(Object delegate, View host,
221                AccessibilityEvent event) {
222            AccessibilityDelegateCompatIcs.sendAccessibilityEventUnchecked(delegate, host, event);
223        }
224    }
225
226    static class AccessibilityDelegateJellyBeanImpl extends AccessibilityDelegateIcsImpl {
227        @Override
228        public Object newAccessiblityDelegateBridge(final AccessibilityDelegateCompat compat) {
229            return AccessibilityDelegateCompatJellyBean.newAccessibilityDelegateBridge(
230                    new AccessibilityDelegateCompatJellyBean
231                            .AccessibilityDelegateBridgeJellyBean() {
232                @Override
233                public boolean dispatchPopulateAccessibilityEvent(View host,
234                        AccessibilityEvent event) {
235                    return compat.dispatchPopulateAccessibilityEvent(host, event);
236                }
237
238                @Override
239                public void onInitializeAccessibilityEvent(View host, AccessibilityEvent event) {
240                    compat.onInitializeAccessibilityEvent(host, event);
241                }
242
243                @Override
244                public void onInitializeAccessibilityNodeInfo(View host, Object info) {
245                    compat.onInitializeAccessibilityNodeInfo(host,
246                            new AccessibilityNodeInfoCompat(info));
247                }
248
249                @Override
250                public void onPopulateAccessibilityEvent(View host, AccessibilityEvent event) {
251                    compat.onPopulateAccessibilityEvent(host, event);
252                }
253
254                @Override
255                public boolean onRequestSendAccessibilityEvent(ViewGroup host, View child,
256                        AccessibilityEvent event) {
257                    return compat.onRequestSendAccessibilityEvent(host, child, event);
258                }
259
260                @Override
261                public void sendAccessibilityEvent(View host, int eventType) {
262                    compat.sendAccessibilityEvent(host, eventType);
263                }
264
265                @Override
266                public void sendAccessibilityEventUnchecked(View host, AccessibilityEvent event) {
267                    compat.sendAccessibilityEventUnchecked(host, event);
268                }
269
270                @Override
271                public Object getAccessibilityNodeProvider(View host) {
272                    AccessibilityNodeProviderCompat provider =
273                        compat.getAccessibilityNodeProvider(host);
274                    return (provider != null) ? provider.getProvider() : null;
275                }
276
277                @Override
278                public boolean performAccessibilityAction(View host, int action, Bundle args) {
279                    return compat.performAccessibilityAction(host, action, args);
280                }
281            });
282        }
283
284        @Override
285        public AccessibilityNodeProviderCompat getAccessibilityNodeProvider(Object delegate,
286                View host) {
287            Object provider = AccessibilityDelegateCompatJellyBean.getAccessibilityNodeProvider(
288                    delegate, host);
289            if (provider != null) {
290                return new AccessibilityNodeProviderCompat(provider);
291            }
292            return null;
293        }
294
295        @Override
296        public boolean performAccessibilityAction(Object delegate, View host, int action,
297                Bundle args) {
298            return AccessibilityDelegateCompatJellyBean.performAccessibilityAction(delegate,
299                    host, action, args);
300        }
301    }
302
303    private static final AccessibilityDelegateImpl IMPL;
304    private static final Object DEFAULT_DELEGATE;
305
306    static {
307        if (Build.VERSION.SDK_INT >= 16) { // JellyBean
308            IMPL = new AccessibilityDelegateJellyBeanImpl();
309        } else if (Build.VERSION.SDK_INT >= 14) { // ICS
310            IMPL = new AccessibilityDelegateIcsImpl();
311        } else {
312            IMPL = new AccessibilityDelegateStubImpl();
313        }
314        DEFAULT_DELEGATE = IMPL.newAccessiblityDelegateDefaultImpl();
315    }
316
317    final Object mBridge;
318
319    /**
320     * Creates a new instance.
321     */
322    public AccessibilityDelegateCompat() {
323        mBridge = IMPL.newAccessiblityDelegateBridge(this);
324    }
325
326    /**
327     * @return The wrapped bridge implementation.
328     */
329    Object getBridge() {
330        return mBridge;
331    }
332
333    /**
334     * Sends an accessibility event of the given type. If accessibility is not
335     * enabled this method has no effect.
336     * <p>
337     * The default implementation behaves as {@link View#sendAccessibilityEvent(int)
338     * View#sendAccessibilityEvent(int)} for the case of no accessibility delegate
339     * been set.
340     * </p>
341     *
342     * @param host The View hosting the delegate.
343     * @param eventType The type of the event to send.
344     *
345     * @see View#sendAccessibilityEvent(int) View#sendAccessibilityEvent(int)
346     */
347    public void sendAccessibilityEvent(View host, int eventType) {
348        IMPL.sendAccessibilityEvent(DEFAULT_DELEGATE, host, eventType);
349    }
350
351    /**
352     * Sends an accessibility event. This method behaves exactly as
353     * {@link #sendAccessibilityEvent(View, int)} but takes as an argument an
354     * empty {@link AccessibilityEvent} and does not perform a check whether
355     * accessibility is enabled.
356     * <p>
357     * The default implementation behaves as
358     * {@link View#sendAccessibilityEventUnchecked(AccessibilityEvent)
359     * View#sendAccessibilityEventUnchecked(AccessibilityEvent)} for
360     * the case of no accessibility delegate been set.
361     * </p>
362     *
363     * @param host The View hosting the delegate.
364     * @param event The event to send.
365     *
366     * @see View#sendAccessibilityEventUnchecked(AccessibilityEvent)
367     *      View#sendAccessibilityEventUnchecked(AccessibilityEvent)
368     */
369    public void sendAccessibilityEventUnchecked(View host, AccessibilityEvent event) {
370        IMPL.sendAccessibilityEventUnchecked(DEFAULT_DELEGATE, host, event);
371    }
372
373    /**
374     * Dispatches an {@link AccessibilityEvent} to the host {@link View} first and then
375     * to its children for adding their text content to the event.
376     * <p>
377     * The default implementation behaves as
378     * {@link View#dispatchPopulateAccessibilityEvent(AccessibilityEvent)
379     * View#dispatchPopulateAccessibilityEvent(AccessibilityEvent)} for
380     * the case of no accessibility delegate been set.
381     * </p>
382     *
383     * @param host The View hosting the delegate.
384     * @param event The event.
385     * @return True if the event population was completed.
386     *
387     * @see View#dispatchPopulateAccessibilityEvent(AccessibilityEvent)
388     *      View#dispatchPopulateAccessibilityEvent(AccessibilityEvent)
389     */
390    public boolean dispatchPopulateAccessibilityEvent(View host, AccessibilityEvent event) {
391        return IMPL.dispatchPopulateAccessibilityEvent(DEFAULT_DELEGATE, host, event);
392    }
393
394    /**
395     * Gives a chance to the host View to populate the accessibility event with its
396     * text content.
397     * <p>
398     * The default implementation behaves as
399     * {@link ViewCompat#onPopulateAccessibilityEvent(View, AccessibilityEvent)
400     * ViewCompat#onPopulateAccessibilityEvent(AccessibilityEvent)} for
401     * the case of no accessibility delegate been set.
402     * </p>
403     *
404     * @param host The View hosting the delegate.
405     * @param event The accessibility event which to populate.
406     *
407     * @see ViewCompat#onPopulateAccessibilityEvent(View ,AccessibilityEvent)
408     *      ViewCompat#onPopulateAccessibilityEvent(View, AccessibilityEvent)
409     */
410    public void onPopulateAccessibilityEvent(View host, AccessibilityEvent event) {
411        IMPL.onPopulateAccessibilityEvent(DEFAULT_DELEGATE, host, event);
412    }
413
414    /**
415     * Initializes an {@link AccessibilityEvent} with information about the
416     * the host View which is the event source.
417     * <p>
418     * The default implementation behaves as
419     * {@link ViewCompat#onInitializeAccessibilityEvent(View v, AccessibilityEvent event)
420     * ViewCompat#onInitalizeAccessibilityEvent(View v, AccessibilityEvent event)} for
421     * the case of no accessibility delegate been set.
422     * </p>
423     *
424     * @param host The View hosting the delegate.
425     * @param event The event to initialize.
426     *
427     * @see ViewCompat#onInitializeAccessibilityEvent(View, AccessibilityEvent)
428     *      ViewCompat#onInitializeAccessibilityEvent(View, AccessibilityEvent)
429     */
430    public void onInitializeAccessibilityEvent(View host, AccessibilityEvent event) {
431        IMPL.onInitializeAccessibilityEvent(DEFAULT_DELEGATE, host, event);
432    }
433
434    /**
435     * Initializes an {@link AccessibilityNodeInfoCompat} with information about the host view.
436     * <p>
437     * The default implementation behaves as
438     * {@link ViewCompat#onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfoCompat)
439     * ViewCompat#onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfoCompat)} for
440     * the case of no accessibility delegate been set.
441     * </p>
442     *
443     * @param host The View hosting the delegate.
444     * @param info The instance to initialize.
445     *
446     * @see ViewCompat#onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfoCompat)
447     *      ViewCompat#onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfoCompat)
448     */
449    public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) {
450        IMPL.onInitializeAccessibilityNodeInfo(DEFAULT_DELEGATE, host, info);
451    }
452
453    /**
454     * Called when a child of the host View has requested sending an
455     * {@link AccessibilityEvent} and gives an opportunity to the parent (the host)
456     * to augment the event.
457     * <p>
458     * The default implementation behaves as
459     * {@link ViewGroupCompat#onRequestSendAccessibilityEvent(ViewGroup, View, AccessibilityEvent)
460     * ViewGroupCompat#onRequestSendAccessibilityEvent(ViewGroup, View, AccessibilityEvent)} for
461     * the case of no accessibility delegate been set.
462     * </p>
463     *
464     * @param host The View hosting the delegate.
465     * @param child The child which requests sending the event.
466     * @param event The event to be sent.
467     * @return True if the event should be sent
468     *
469     * @see ViewGroupCompat#onRequestSendAccessibilityEvent(ViewGroup, View, AccessibilityEvent)
470     *      ViewGroupCompat#onRequestSendAccessibilityEvent(ViewGroup, View, AccessibilityEvent)
471     */
472    public boolean onRequestSendAccessibilityEvent(ViewGroup host, View child,
473            AccessibilityEvent event) {
474        return IMPL.onRequestSendAccessibilityEvent(DEFAULT_DELEGATE, host, child, event);
475    }
476
477    /**
478     * Gets the provider for managing a virtual view hierarchy rooted at this View
479     * and reported to {@link android.accessibilityservice.AccessibilityService}s
480     * that explore the window content.
481     * <p>
482     * The default implementation behaves as
483     * {@link ViewCompat#getAccessibilityNodeProvider(View) ViewCompat#getAccessibilityNodeProvider(View)}
484     * for the case of no accessibility delegate been set.
485     * </p>
486     *
487     * @return The provider.
488     *
489     * @see AccessibilityNodeProviderCompat
490     */
491    public AccessibilityNodeProviderCompat getAccessibilityNodeProvider(View host) {
492        return IMPL.getAccessibilityNodeProvider(DEFAULT_DELEGATE, host);
493    }
494
495    /**
496     * Performs the specified accessibility action on the view. For
497     * possible accessibility actions look at {@link AccessibilityNodeInfoCompat}.
498     * <p>
499     * The default implementation behaves as
500     * {@link View#performAccessibilityAction(int, Bundle)
501     *  View#performAccessibilityAction(int, Bundle)} for the case of
502     *  no accessibility delegate been set.
503     * </p>
504     *
505     * @param action The action to perform.
506     * @return Whether the action was performed.
507     *
508     * @see View#performAccessibilityAction(int, Bundle)
509     *      View#performAccessibilityAction(int, Bundle)
510     */
511    public boolean performAccessibilityAction(View host, int action, Bundle args) {
512        return IMPL.performAccessibilityAction(DEFAULT_DELEGATE, host, action, args);
513    }
514}
515