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1 /*
2  * Copyright (C) 2007 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 
17 package android.media;
18 
19 import static android.media.AudioManager.AUDIO_SESSION_ID_GENERATE;
20 
21 import android.annotation.NonNull;
22 import android.annotation.Nullable;
23 import android.content.Context;
24 import android.content.res.AssetFileDescriptor;
25 import android.os.Handler;
26 import android.os.Looper;
27 import android.os.Message;
28 import android.os.ParcelFileDescriptor;
29 import android.os.Trace;
30 import android.util.AndroidRuntimeException;
31 import android.util.Log;
32 
33 import java.io.File;
34 import java.io.FileDescriptor;
35 import java.util.Objects;
36 import java.util.concurrent.atomic.AtomicReference;
37 
38 
39 /**
40  * The SoundPool class manages and plays audio resources for applications.
41  *
42  * <p>A SoundPool is a collection of sound samples that can be loaded into memory
43  * from a resource inside the APK or from a file in the file system. The
44  * SoundPool library uses the MediaCodec service to decode the audio
45  * into raw 16-bit PCM. This allows applications
46  * to ship with compressed streams without having to suffer the CPU load
47  * and latency of decompressing during playback.</p>
48  *
49  * <p>Soundpool sounds are expected to be short as they are
50  * predecoded into memory. Each decoded sound is internally limited to one
51  * megabyte storage, which represents approximately 5.6 seconds at 44.1kHz stereo
52  * (the duration is proportionally longer at lower sample rates or
53  * a channel mask of mono). A decoded audio sound will be truncated if it would
54  * exceed the per-sound one megabyte storage space.</p>
55  *
56  * <p>In addition to low-latency playback, SoundPool can also manage the number
57  * of audio streams being rendered at once. When the SoundPool object is
58  * constructed, the maxStreams parameter sets the maximum number of streams
59  * that can be played at a time from this single SoundPool. SoundPool tracks
60  * the number of active streams. If the maximum number of streams is exceeded,
61  * SoundPool will automatically stop a previously playing stream based first
62  * on priority and then by age within that priority. Limiting the maximum
63  * number of streams helps to cap CPU loading and reducing the likelihood that
64  * audio mixing will impact visuals or UI performance.</p>
65  *
66  * <p>Sounds can be looped by setting a non-zero loop value. A value of -1
67  * causes the sound to loop forever. In this case, the application must
68  * explicitly call the stop() function to stop the sound. Any other non-zero
69  * value will cause the sound to repeat the specified number of times, e.g.
70  * a value of 3 causes the sound to play a total of 4 times.</p>
71  *
72  * <p>The playback rate can also be changed. A playback rate of 1.0 causes
73  * the sound to play at its original frequency (resampled, if necessary,
74  * to the hardware output frequency). A playback rate of 2.0 causes the
75  * sound to play at twice its original frequency, and a playback rate of
76  * 0.5 causes it to play at half its original frequency. The playback
77  * rate range is 0.5 to 2.0.</p>
78  *
79  * <p>Priority runs low to high, i.e. higher numbers are higher priority.
80  * Priority is used when a call to play() would cause the number of active
81  * streams to exceed the value established by the maxStreams parameter when
82  * the SoundPool was created. In this case, the stream allocator will stop
83  * the lowest priority stream. If there are multiple streams with the same
84  * low priority, it will choose the oldest stream to stop. In the case
85  * where the priority of the new stream is lower than all the active
86  * streams, the new sound will not play and the play() function will return
87  * a streamID of zero.</p>
88  *
89  * <p>Let's examine a typical use case: A game consists of several levels of
90  * play. For each level, there is a set of unique sounds that are used only
91  * by that level. In this case, the game logic should create a new SoundPool
92  * object when the first level is loaded. The level data itself might contain
93  * the list of sounds to be used by this level. The loading logic iterates
94  * through the list of sounds calling the appropriate SoundPool.load()
95  * function. This should typically be done early in the process to allow time
96  * for decompressing the audio to raw PCM format before they are needed for
97  * playback.</p>
98  *
99  * <p>Once the sounds are loaded and play has started, the application can
100  * trigger sounds by calling SoundPool.play(). Playing streams can be
101  * paused or resumed, and the application can also alter the pitch by
102  * adjusting the playback rate in real-time for doppler or synthesis
103  * effects.</p>
104  *
105  * <p>Note that since streams can be stopped due to resource constraints, the
106  * streamID is a reference to a particular instance of a stream. If the stream
107  * is stopped to allow a higher priority stream to play, the stream is no
108  * longer valid. However, the application is allowed to call methods on
109  * the streamID without error. This may help simplify program logic since
110  * the application need not concern itself with the stream lifecycle.</p>
111  *
112  * <p>In our example, when the player has completed the level, the game
113  * logic should call SoundPool.release() to release all the native resources
114  * in use and then set the SoundPool reference to null. If the player starts
115  * another level, a new SoundPool is created, sounds are loaded, and play
116  * resumes.</p>
117  */
118 public class SoundPool extends PlayerBase {
119     static { System.loadLibrary("soundpool"); }
120 
121     // SoundPool messages
122     //
123     // must match SoundPool.h
124     private static final int SAMPLE_LOADED = 1;
125 
126     private final static String TAG = "SoundPool";
127     private final static boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
128 
129     private final AtomicReference<EventHandler> mEventHandler = new AtomicReference<>(null);
130 
131     private long mNativeContext; // accessed by native methods
132 
133     private boolean mHasAppOpsPlayAudio;
134 
135     private final AudioAttributes mAttributes;
136 
137     /**
138      * Constructor. Constructs a SoundPool object with the following
139      * characteristics:
140      *
141      * @param maxStreams the maximum number of simultaneous streams for this
142      *                   SoundPool object
143      * @param streamType the audio stream type as described in AudioManager
144      *                   For example, game applications will normally use
145      *                   {@link AudioManager#STREAM_MUSIC}.
146      * @param srcQuality the sample-rate converter quality. Currently has no
147      *                   effect. Use 0 for the default.
148      * @return a SoundPool object, or null if creation failed
149      * @deprecated use {@link SoundPool.Builder} instead to create and configure a
150      *     SoundPool instance
151      */
SoundPool(int maxStreams, int streamType, int srcQuality)152     public SoundPool(int maxStreams, int streamType, int srcQuality) {
153         this(/*context=*/null, maxStreams,
154                 new AudioAttributes.Builder().setInternalLegacyStreamType(streamType).build(),
155                 AUDIO_SESSION_ID_GENERATE);
156         PlayerBase.deprecateStreamTypeForPlayback(streamType, "SoundPool", "SoundPool()");
157     }
158 
SoundPool(@ullable Context context, int maxStreams, @NonNull AudioAttributes attributes, int sessionId)159     private SoundPool(@Nullable Context context, int maxStreams,
160             @NonNull AudioAttributes attributes, int sessionId) {
161         super(attributes, AudioPlaybackConfiguration.PLAYER_TYPE_JAM_SOUNDPOOL);
162 
163         // do native setup
164         if (native_setup(maxStreams, attributes, getCurrentOpPackageName()) != 0) {
165             throw new RuntimeException("Native setup failed");
166         }
167         mAttributes = attributes;
168 
169         baseRegisterPlayer(resolvePlaybackSessionId(context, sessionId));
170     }
171 
172     /**
173      * Release the SoundPool resources.
174      *
175      * Release all memory and native resources used by the SoundPool
176      * object. The SoundPool can no longer be used and the reference
177      * should be set to null.
178      */
release()179     public final void release() {
180         baseRelease();
181         native_release();
182     }
183 
native_release()184     private native final void native_release();
185 
finalize()186     protected void finalize() { release(); }
187 
188     /**
189      * Load the sound from the specified path.
190      *
191      * @param path the path to the audio file
192      * @param priority the priority of the sound. Currently has no effect. Use
193      *                 a value of 1 for future compatibility.
194      * @return a sound ID. This value can be used to play or unload the sound.
195      */
load(String path, int priority)196     public int load(String path, int priority) {
197         int id = 0;
198         try {
199             File f = new File(path);
200             ParcelFileDescriptor fd = ParcelFileDescriptor.open(f,
201                     ParcelFileDescriptor.MODE_READ_ONLY);
202             if (fd != null) {
203                 id = _load(fd.getFileDescriptor(), 0, f.length(), priority);
204                 fd.close();
205             }
206         } catch (java.io.IOException e) {
207             Log.e(TAG, "error loading " + path);
208         }
209         return id;
210     }
211 
212     /**
213      * Load the sound from the specified APK resource.
214      *
215      * Note that the extension is dropped. For example, if you want to load
216      * a sound from the raw resource file "explosion.mp3", you would specify
217      * "R.raw.explosion" as the resource ID. Note that this means you cannot
218      * have both an "explosion.wav" and an "explosion.mp3" in the res/raw
219      * directory.
220      *
221      * @param context the application context
222      * @param resId the resource ID
223      * @param priority the priority of the sound. Currently has no effect. Use
224      *                 a value of 1 for future compatibility.
225      * @return a sound ID. This value can be used to play or unload the sound.
226      */
load(Context context, int resId, int priority)227     public int load(Context context, int resId, int priority) {
228         AssetFileDescriptor afd = context.getResources().openRawResourceFd(resId);
229         int id = 0;
230         if (afd != null) {
231             id = _load(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength(), priority);
232             try {
233                 afd.close();
234             } catch (java.io.IOException ex) {
235                 //Log.d(TAG, "close failed:", ex);
236             }
237         }
238         return id;
239     }
240 
241     /**
242      * Load the sound from an asset file descriptor.
243      *
244      * @param afd an asset file descriptor
245      * @param priority the priority of the sound. Currently has no effect. Use
246      *                 a value of 1 for future compatibility.
247      * @return a sound ID. This value can be used to play or unload the sound.
248      */
load(AssetFileDescriptor afd, int priority)249     public int load(AssetFileDescriptor afd, int priority) {
250         if (afd != null) {
251             long len = afd.getLength();
252             if (len < 0) {
253                 throw new AndroidRuntimeException("no length for fd");
254             }
255             return _load(afd.getFileDescriptor(), afd.getStartOffset(), len, priority);
256         } else {
257             return 0;
258         }
259     }
260 
261     /**
262      * Load the sound from a FileDescriptor.
263      *
264      * This version is useful if you store multiple sounds in a single
265      * binary. The offset specifies the offset from the start of the file
266      * and the length specifies the length of the sound within the file.
267      *
268      * @param fd a FileDescriptor object
269      * @param offset offset to the start of the sound
270      * @param length length of the sound
271      * @param priority the priority of the sound. Currently has no effect. Use
272      *                 a value of 1 for future compatibility.
273      * @return a sound ID. This value can be used to play or unload the sound.
274      */
load(FileDescriptor fd, long offset, long length, int priority)275     public int load(FileDescriptor fd, long offset, long length, int priority) {
276         return _load(fd, offset, length, priority);
277     }
278 
279     /**
280      * Unload a sound from a sound ID.
281      *
282      * Unloads the sound specified by the soundID. This is the value
283      * returned by the load() function. Returns true if the sound is
284      * successfully unloaded, false if the sound was already unloaded.
285      *
286      * @param soundID a soundID returned by the load() function
287      * @return true if just unloaded, false if previously unloaded
288      */
unload(int soundID)289     public native final boolean unload(int soundID);
290 
291     /**
292      * Play a sound from a sound ID.
293      *
294      * Play the sound specified by the soundID. This is the value
295      * returned by the load() function. Returns a non-zero streamID
296      * if successful, zero if it fails. The streamID can be used to
297      * further control playback. Note that calling play() may cause
298      * another sound to stop playing if the maximum number of active
299      * streams is exceeded. A loop value of -1 means loop forever,
300      * a value of 0 means don't loop, other values indicate the
301      * number of repeats, e.g. a value of 1 plays the audio twice.
302      * The playback rate allows the application to vary the playback
303      * rate (pitch) of the sound. A value of 1.0 means play back at
304      * the original frequency. A value of 2.0 means play back twice
305      * as fast, and a value of 0.5 means playback at half speed.
306      *
307      * @param soundID a soundID returned by the load() function
308      * @param leftVolume left volume value (range = 0.0 to 1.0)
309      * @param rightVolume right volume value (range = 0.0 to 1.0)
310      * @param priority stream priority (0 = lowest priority)
311      * @param loop loop mode (0 = no loop, -1 = loop forever)
312      * @param rate playback rate (1.0 = normal playback, range 0.5 to 2.0)
313      * @return non-zero streamID if successful, zero if failed
314      */
play(int soundID, float leftVolume, float rightVolume, int priority, int loop, float rate)315     public final int play(int soundID, float leftVolume, float rightVolume,
316             int priority, int loop, float rate) {
317         // FIXME: b/174876164 implement device id for soundpool
318         try {
319             Trace.traceBegin(Trace.TRACE_TAG_AUDIO, "SoundPool.play");
320             baseStart(new int[0]);
321             return _play(soundID, leftVolume, rightVolume, priority, loop, rate, getPlayerIId());
322         } finally {
323             Trace.traceEnd(Trace.TRACE_TAG_AUDIO);
324         }
325     }
326 
327     /**
328      * Pause a playback stream.
329      *
330      * Pause the stream specified by the streamID. This is the
331      * value returned by the play() function. If the stream is
332      * playing, it will be paused. If the stream is not playing
333      * (e.g. is stopped or was previously paused), calling this
334      * function will have no effect.
335      *
336      * @param streamID a streamID returned by the play() function
337      */
pause(int streamID)338     public native final void pause(int streamID);
339 
340     /**
341      * Resume a playback stream.
342      *
343      * Resume the stream specified by the streamID. This
344      * is the value returned by the play() function. If the stream
345      * is paused, this will resume playback. If the stream was not
346      * previously paused, calling this function will have no effect.
347      *
348      * @param streamID a streamID returned by the play() function
349      */
resume(int streamID)350     public native final void resume(int streamID);
351 
352     /**
353      * Pause all active streams.
354      *
355      * Pause all streams that are currently playing. This function
356      * iterates through all the active streams and pauses any that
357      * are playing. It also sets a flag so that any streams that
358      * are playing can be resumed by calling autoResume().
359      */
autoPause()360     public native final void autoPause();
361 
362     /**
363      * Resume all previously active streams.
364      *
365      * Automatically resumes all streams that were paused in previous
366      * calls to autoPause().
367      */
autoResume()368     public native final void autoResume();
369 
370     /**
371      * Stop a playback stream.
372      *
373      * Stop the stream specified by the streamID. This
374      * is the value returned by the play() function. If the stream
375      * is playing, it will be stopped. It also releases any native
376      * resources associated with this stream. If the stream is not
377      * playing, it will have no effect.
378      *
379      * @param streamID a streamID returned by the play() function
380      */
stop(int streamID)381     public native final void stop(int streamID);
382 
383     /**
384      * Set stream volume.
385      *
386      * Sets the volume on the stream specified by the streamID.
387      * This is the value returned by the play() function. The
388      * value must be in the range of 0.0 to 1.0. If the stream does
389      * not exist, it will have no effect.
390      *
391      * @param streamID a streamID returned by the play() function
392      * @param leftVolume left volume value (range = 0.0 to 1.0)
393      * @param rightVolume right volume value (range = 0.0 to 1.0)
394      */
setVolume(int streamID, float leftVolume, float rightVolume)395     public final void setVolume(int streamID, float leftVolume, float rightVolume) {
396         // unlike other subclasses of PlayerBase, we are not calling
397         // baseSetVolume(leftVolume, rightVolume) as we need to keep track of each
398         // volume separately for each player, so we still send the command, but
399         // handle mute/unmute separately through playerSetVolume()
400         _setVolume(streamID, leftVolume, rightVolume);
401     }
402 
403     @Override
playerApplyVolumeShaper( @onNull VolumeShaper.Configuration configuration, @Nullable VolumeShaper.Operation operation)404     /* package */ int playerApplyVolumeShaper(
405             @NonNull VolumeShaper.Configuration configuration,
406             @Nullable VolumeShaper.Operation operation) {
407         return -1;
408     }
409 
410     @Override
playerGetVolumeShaperState(int id)411     /* package */ @Nullable VolumeShaper.State playerGetVolumeShaperState(int id) {
412         return null;
413     }
414 
415     @Override
playerSetVolume(boolean muting, float leftVolume, float rightVolume)416     void playerSetVolume(boolean muting, float leftVolume, float rightVolume) {
417         // not used here to control the player volume directly, but used to mute/unmute
418         _mute(muting);
419     }
420 
421     @Override
playerSetAuxEffectSendLevel(boolean muting, float level)422     int playerSetAuxEffectSendLevel(boolean muting, float level) {
423         // no aux send functionality so no-op
424         return AudioSystem.SUCCESS;
425     }
426 
427     @Override
playerStart()428     void playerStart() {
429         // FIXME implement resuming any paused sound
430     }
431 
432     @Override
playerPause()433     void playerPause() {
434         // FIXME implement pausing any playing sound
435     }
436 
437     @Override
playerStop()438     void playerStop() {
439         // FIXME implement pausing any playing sound
440     }
441 
442     /**
443      * Similar, except set volume of all channels to same value.
444      * @hide
445      */
setVolume(int streamID, float volume)446     public void setVolume(int streamID, float volume) {
447         setVolume(streamID, volume, volume);
448     }
449 
450     /**
451      * Change stream priority.
452      *
453      * Change the priority of the stream specified by the streamID.
454      * This is the value returned by the play() function. Affects the
455      * order in which streams are re-used to play new sounds. If the
456      * stream does not exist, it will have no effect.
457      *
458      * @param streamID a streamID returned by the play() function
459      */
setPriority(int streamID, int priority)460     public native final void setPriority(int streamID, int priority);
461 
462     /**
463      * Set loop mode.
464      *
465      * Change the loop mode. A loop value of -1 means loop forever,
466      * a value of 0 means don't loop, other values indicate the
467      * number of repeats, e.g. a value of 1 plays the audio twice.
468      * If the stream does not exist, it will have no effect.
469      *
470      * @param streamID a streamID returned by the play() function
471      * @param loop loop mode (0 = no loop, -1 = loop forever)
472      */
setLoop(int streamID, int loop)473     public native final void setLoop(int streamID, int loop);
474 
475     /**
476      * Change playback rate.
477      *
478      * The playback rate allows the application to vary the playback
479      * rate (pitch) of the sound. A value of 1.0 means playback at
480      * the original frequency. A value of 2.0 means playback twice
481      * as fast, and a value of 0.5 means playback at half speed.
482      * If the stream does not exist, it will have no effect.
483      *
484      * @param streamID a streamID returned by the play() function
485      * @param rate playback rate (1.0 = normal playback, range 0.5 to 2.0)
486      */
setRate(int streamID, float rate)487     public native final void setRate(int streamID, float rate);
488 
489     public interface OnLoadCompleteListener {
490         /**
491          * Called when a sound has completed loading.
492          *
493          * @param soundPool SoundPool object from the load() method
494          * @param sampleId the sample ID of the sound loaded.
495          * @param status the status of the load operation (0 = success)
496          */
onLoadComplete(SoundPool soundPool, int sampleId, int status)497         public void onLoadComplete(SoundPool soundPool, int sampleId, int status);
498     }
499 
500     /**
501      * Sets the callback hook for the OnLoadCompleteListener.
502      */
setOnLoadCompleteListener(OnLoadCompleteListener listener)503     public void setOnLoadCompleteListener(OnLoadCompleteListener listener) {
504         if (listener == null) {
505             mEventHandler.set(null);
506             return;
507         }
508 
509         Looper looper;
510         if ((looper = Looper.myLooper()) != null) {
511             mEventHandler.set(new EventHandler(looper, listener));
512         } else if ((looper = Looper.getMainLooper()) != null) {
513             mEventHandler.set(new EventHandler(looper, listener));
514         } else {
515             mEventHandler.set(null);
516         }
517     }
518 
_load(FileDescriptor fd, long offset, long length, int priority)519     private native final int _load(FileDescriptor fd, long offset, long length, int priority);
520 
native_setup(int maxStreams, @NonNull Object attributes, @NonNull String opPackageName)521     private native int native_setup(int maxStreams,
522             @NonNull Object/*AudioAttributes*/ attributes, @NonNull String opPackageName);
523 
_play(int soundID, float leftVolume, float rightVolume, int priority, int loop, float rate, int playerIId)524     private native final int _play(int soundID, float leftVolume, float rightVolume,
525             int priority, int loop, float rate, int playerIId);
526 
_setVolume(int streamID, float leftVolume, float rightVolume)527     private native final void _setVolume(int streamID, float leftVolume, float rightVolume);
528 
_mute(boolean muting)529     private native final void _mute(boolean muting);
530 
531     // post event from native code to message handler
532     @SuppressWarnings("unchecked")
postEventFromNative(int msg, int arg1, int arg2, Object obj)533     private void postEventFromNative(int msg, int arg1, int arg2, Object obj) {
534         Handler eventHandler = mEventHandler.get();
535         if (eventHandler == null) {
536             return;
537         }
538         Message message = eventHandler.obtainMessage(msg, arg1, arg2, obj);
539         eventHandler.sendMessage(message);
540     }
541 
542     private final class EventHandler extends Handler {
543         private final OnLoadCompleteListener mOnLoadCompleteListener;
544 
EventHandler(Looper looper, @NonNull OnLoadCompleteListener onLoadCompleteListener)545         EventHandler(Looper looper, @NonNull OnLoadCompleteListener onLoadCompleteListener) {
546             super(looper);
547             mOnLoadCompleteListener = onLoadCompleteListener;
548         }
549 
550         @Override
handleMessage(Message msg)551         public void handleMessage(Message msg) {
552             if (msg.what != SAMPLE_LOADED) {
553                 Log.e(TAG, "Unknown message type " + msg.what);
554                 return;
555             }
556 
557             if (DEBUG) Log.d(TAG, "Sample " + msg.arg1 + " loaded");
558             mOnLoadCompleteListener.onLoadComplete(SoundPool.this, msg.arg1, msg.arg2);
559         }
560     }
561 
562     /**
563      * Builder class for {@link SoundPool} objects.
564      */
565     public static class Builder {
566         private int mMaxStreams = 1;
567         private AudioAttributes mAudioAttributes;
568         private Context mContext;
569         private int mSessionId = AUDIO_SESSION_ID_GENERATE;
570 
571         /**
572          * Constructs a new Builder with the defaults format values.
573          * If not provided, the maximum number of streams is 1 (see {@link #setMaxStreams(int)} to
574          * change it), and the audio attributes have a usage value of
575          * {@link AudioAttributes#USAGE_MEDIA} (see {@link #setAudioAttributes(AudioAttributes)} to
576          * change them).
577          */
Builder()578         public Builder() {
579         }
580 
581         /**
582          * Sets the maximum of number of simultaneous streams that can be played simultaneously.
583          * @param maxStreams a value equal to 1 or greater.
584          * @return the same Builder instance
585          * @throws IllegalArgumentException
586          */
setMaxStreams(int maxStreams)587         public Builder setMaxStreams(int maxStreams) throws IllegalArgumentException {
588             if (maxStreams <= 0) {
589                 throw new IllegalArgumentException(
590                         "Strictly positive value required for the maximum number of streams");
591             }
592             mMaxStreams = maxStreams;
593             return this;
594         }
595 
596         /**
597          * Sets the {@link AudioAttributes}. For examples, game applications will use attributes
598          * built with usage information set to {@link AudioAttributes#USAGE_GAME}.
599          * @param attributes a non-null
600          * @return
601          */
setAudioAttributes(AudioAttributes attributes)602         public Builder setAudioAttributes(AudioAttributes attributes)
603                 throws IllegalArgumentException {
604             if (attributes == null) {
605                 throw new IllegalArgumentException("Invalid null AudioAttributes");
606             }
607             mAudioAttributes = attributes;
608             return this;
609         }
610 
611         /**
612          * Sets the session ID the {@link SoundPool} will be attached to.
613          *
614          * Note, that if there's a device specific session id associated with the context
615          * (see {@link Builder#setContext(Context)}), explicitly setting a session id using this
616          * method will override it.
617          *
618          * @param sessionId a strictly positive ID number retrieved from another player or
619          *   allocated by {@link AudioManager} via {@link AudioManager#generateAudioSessionId()},
620          *   or {@link AudioManager#AUDIO_SESSION_ID_GENERATE}.
621          * @return the same {@link Builder} instance
622          * @throws IllegalArgumentException when sessionId is invalid.
623          */
setAudioSessionId(int sessionId)624         public @NonNull Builder setAudioSessionId(int sessionId) {
625             if ((sessionId != AUDIO_SESSION_ID_GENERATE) && (sessionId < 1)) {
626                 throw new IllegalArgumentException("Invalid audio session ID " + sessionId);
627             }
628             mSessionId = sessionId;
629             return this;
630         }
631 
632         /**
633          * Sets the context the SoundPool belongs to.
634          *
635          * The context will be used to pull information, such as
636          * {@link android.content.AttributionSource} and device specific audio session ids,
637          * which will be associated with the {@link SoundPool}. However, the context itself will
638          * not be retained by the {@link SoundPool} instance after initialization.
639          *
640          * @param context a non-null {@link Context} instance
641          * @return the same {@link Builder} instance.
642          */
setContext(@onNull Context context)643         public @NonNull Builder setContext(@NonNull Context context) {
644             mContext = Objects.requireNonNull(context);
645             return this;
646         }
647 
build()648         public SoundPool build() {
649             if (mAudioAttributes == null) {
650                 mAudioAttributes = new AudioAttributes.Builder()
651                         .setUsage(AudioAttributes.USAGE_MEDIA).build();
652             }
653             return new SoundPool(mContext, mMaxStreams, mAudioAttributes, mSessionId);
654         }
655     }
656 }
657