下面列出了android.media.AudioTrack#getPlayState ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
private static int writeToAudioTrack(AudioTrack audioTrack, byte[] bytes) {
if (audioTrack.getPlayState() != AudioTrack.PLAYSTATE_PLAYING) {
if (DBG) Log.d(TAG, "AudioTrack not playing, restarting : " + audioTrack.hashCode());
audioTrack.play();
}
int count = 0;
while (count < bytes.length) {
// Note that we don't take bufferCopy.mOffset into account because
// it is guaranteed to be 0.
int written = audioTrack.write(bytes, count, bytes.length);
if (written <= 0) {
break;
}
count += written;
}
return count;
}
/**
* {@link AudioTrack#getPlaybackHeadPosition()} returns a value intended to be interpreted as an
* unsigned 32 bit integer, which also wraps around periodically. This method returns the playback
* head position as a long that will only wrap around if the value exceeds {@link Long#MAX_VALUE}
* (which in practice will never happen).
*
* @return The playback head position, in frames.
*/
private long getPlaybackHeadPosition() {
AudioTrack audioTrack = Assertions.checkNotNull(this.audioTrack);
if (stopTimestampUs != C.TIME_UNSET) {
// Simulate the playback head position up to the total number of frames submitted.
long elapsedTimeSinceStopUs = (SystemClock.elapsedRealtime() * 1000) - stopTimestampUs;
long framesSinceStop = (elapsedTimeSinceStopUs * outputSampleRate) / C.MICROS_PER_SECOND;
return Math.min(endPlaybackHeadPosition, stopPlaybackHeadPosition + framesSinceStop);
}
int state = audioTrack.getPlayState();
if (state == PLAYSTATE_STOPPED) {
// The audio track hasn't been started.
return 0;
}
long rawPlaybackHeadPosition = 0xFFFFFFFFL & audioTrack.getPlaybackHeadPosition();
if (needsPassthroughWorkarounds) {
// Work around an issue with passthrough/direct AudioTracks on platform API versions 21/22
// where the playback head position jumps back to zero on paused passthrough/direct audio
// tracks. See [Internal: b/19187573].
if (state == PLAYSTATE_PAUSED && rawPlaybackHeadPosition == 0) {
passthroughWorkaroundPauseOffset = lastRawPlaybackHeadPosition;
}
rawPlaybackHeadPosition += passthroughWorkaroundPauseOffset;
}
if (Util.SDK_INT <= 29) {
if (rawPlaybackHeadPosition == 0
&& lastRawPlaybackHeadPosition > 0
&& state == PLAYSTATE_PLAYING) {
// If connecting a Bluetooth audio device fails, the AudioTrack may be left in a state
// where its Java API is in the playing state, but the native track is stopped. When this
// happens the playback head position gets stuck at zero. In this case, return the old
// playback head position and force the track to be reset after
// {@link #FORCE_RESET_WORKAROUND_TIMEOUT_MS} has elapsed.
if (forceResetWorkaroundTimeMs == C.TIME_UNSET) {
forceResetWorkaroundTimeMs = SystemClock.elapsedRealtime();
}
return lastRawPlaybackHeadPosition;
} else {
forceResetWorkaroundTimeMs = C.TIME_UNSET;
}
}
if (lastRawPlaybackHeadPosition > rawPlaybackHeadPosition) {
// The value must have wrapped around.
rawPlaybackHeadWrapCount++;
}
lastRawPlaybackHeadPosition = rawPlaybackHeadPosition;
return rawPlaybackHeadPosition + (rawPlaybackHeadWrapCount << 32);
}
private void blockUntilCompletion(AudioTrack audioTrack) {
final int lengthInFrames = mBytesWritten / mBytesPerFrame;
int previousPosition = -1;
int currentPosition = 0;
long blockedTimeMs = 0;
while ((currentPosition = audioTrack.getPlaybackHeadPosition()) < lengthInFrames &&
audioTrack.getPlayState() == AudioTrack.PLAYSTATE_PLAYING && !mStopped) {
final long estimatedTimeMs = ((lengthInFrames - currentPosition) * 1000) /
audioTrack.getSampleRate();
final long sleepTimeMs = clip(estimatedTimeMs, MIN_SLEEP_TIME_MS, MAX_SLEEP_TIME_MS);
// Check if the audio track has made progress since the last loop
// iteration. We should then add in the amount of time that was
// spent sleeping in the last iteration.
if (currentPosition == previousPosition) {
// This works only because the sleep time that would have been calculated
// would be the same in the previous iteration too.
blockedTimeMs += sleepTimeMs;
// If we've taken too long to make progress, bail.
if (blockedTimeMs > MAX_PROGRESS_WAIT_MS) {
Log.w(TAG, "Waited unsuccessfully for " + MAX_PROGRESS_WAIT_MS + "ms " +
"for AudioTrack to make progress, Aborting");
break;
}
} else {
blockedTimeMs = 0;
}
previousPosition = currentPosition;
if (DBG) {
Log.d(TAG, "About to sleep for : " + sleepTimeMs + " ms," +
" Playback position : " + currentPosition + ", Length in frames : "
+ lengthInFrames);
}
try {
Thread.sleep(sleepTimeMs);
} catch (InterruptedException ie) {
break;
}
}
}
/**
* {@link AudioTrack#getPlaybackHeadPosition()} returns a value intended to be interpreted as an
* unsigned 32 bit integer, which also wraps around periodically. This method returns the playback
* head position as a long that will only wrap around if the value exceeds {@link Long#MAX_VALUE}
* (which in practice will never happen).
*
* @return The playback head position, in frames.
*/
private long getPlaybackHeadPosition() {
AudioTrack audioTrack = Assertions.checkNotNull(this.audioTrack);
if (stopTimestampUs != C.TIME_UNSET) {
// Simulate the playback head position up to the total number of frames submitted.
long elapsedTimeSinceStopUs = (SystemClock.elapsedRealtime() * 1000) - stopTimestampUs;
long framesSinceStop = (elapsedTimeSinceStopUs * outputSampleRate) / C.MICROS_PER_SECOND;
return Math.min(endPlaybackHeadPosition, stopPlaybackHeadPosition + framesSinceStop);
}
int state = audioTrack.getPlayState();
if (state == PLAYSTATE_STOPPED) {
// The audio track hasn't been started.
return 0;
}
long rawPlaybackHeadPosition = 0xFFFFFFFFL & audioTrack.getPlaybackHeadPosition();
if (needsPassthroughWorkarounds) {
// Work around an issue with passthrough/direct AudioTracks on platform API versions 21/22
// where the playback head position jumps back to zero on paused passthrough/direct audio
// tracks. See [Internal: b/19187573].
if (state == PLAYSTATE_PAUSED && rawPlaybackHeadPosition == 0) {
passthroughWorkaroundPauseOffset = lastRawPlaybackHeadPosition;
}
rawPlaybackHeadPosition += passthroughWorkaroundPauseOffset;
}
if (Util.SDK_INT <= 28) {
if (rawPlaybackHeadPosition == 0
&& lastRawPlaybackHeadPosition > 0
&& state == PLAYSTATE_PLAYING) {
// If connecting a Bluetooth audio device fails, the AudioTrack may be left in a state
// where its Java API is in the playing state, but the native track is stopped. When this
// happens the playback head position gets stuck at zero. In this case, return the old
// playback head position and force the track to be reset after
// {@link #FORCE_RESET_WORKAROUND_TIMEOUT_MS} has elapsed.
if (forceResetWorkaroundTimeMs == C.TIME_UNSET) {
forceResetWorkaroundTimeMs = SystemClock.elapsedRealtime();
}
return lastRawPlaybackHeadPosition;
} else {
forceResetWorkaroundTimeMs = C.TIME_UNSET;
}
}
if (lastRawPlaybackHeadPosition > rawPlaybackHeadPosition) {
// The value must have wrapped around.
rawPlaybackHeadWrapCount++;
}
lastRawPlaybackHeadPosition = rawPlaybackHeadPosition;
return rawPlaybackHeadPosition + (rawPlaybackHeadWrapCount << 32);
}
/**
* {@link AudioTrack#getPlaybackHeadPosition()} returns a value intended to be interpreted as an
* unsigned 32 bit integer, which also wraps around periodically. This method returns the playback
* head position as a long that will only wrap around if the value exceeds {@link Long#MAX_VALUE}
* (which in practice will never happen).
*
* @return The playback head position, in frames.
*/
private long getPlaybackHeadPosition() {
AudioTrack audioTrack = Assertions.checkNotNull(this.audioTrack);
if (stopTimestampUs != C.TIME_UNSET) {
// Simulate the playback head position up to the total number of frames submitted.
long elapsedTimeSinceStopUs = (SystemClock.elapsedRealtime() * 1000) - stopTimestampUs;
long framesSinceStop = (elapsedTimeSinceStopUs * outputSampleRate) / C.MICROS_PER_SECOND;
return Math.min(endPlaybackHeadPosition, stopPlaybackHeadPosition + framesSinceStop);
}
int state = audioTrack.getPlayState();
if (state == PLAYSTATE_STOPPED) {
// The audio track hasn't been started.
return 0;
}
long rawPlaybackHeadPosition = 0xFFFFFFFFL & audioTrack.getPlaybackHeadPosition();
if (needsPassthroughWorkarounds) {
// Work around an issue with passthrough/direct AudioTracks on platform API versions 21/22
// where the playback head position jumps back to zero on paused passthrough/direct audio
// tracks. See [Internal: b/19187573].
if (state == PLAYSTATE_PAUSED && rawPlaybackHeadPosition == 0) {
passthroughWorkaroundPauseOffset = lastRawPlaybackHeadPosition;
}
rawPlaybackHeadPosition += passthroughWorkaroundPauseOffset;
}
if (Util.SDK_INT <= 28) {
if (rawPlaybackHeadPosition == 0
&& lastRawPlaybackHeadPosition > 0
&& state == PLAYSTATE_PLAYING) {
// If connecting a Bluetooth audio device fails, the AudioTrack may be left in a state
// where its Java API is in the playing state, but the native track is stopped. When this
// happens the playback head position gets stuck at zero. In this case, return the old
// playback head position and force the track to be reset after
// {@link #FORCE_RESET_WORKAROUND_TIMEOUT_MS} has elapsed.
if (forceResetWorkaroundTimeMs == C.TIME_UNSET) {
forceResetWorkaroundTimeMs = SystemClock.elapsedRealtime();
}
return lastRawPlaybackHeadPosition;
} else {
forceResetWorkaroundTimeMs = C.TIME_UNSET;
}
}
if (lastRawPlaybackHeadPosition > rawPlaybackHeadPosition) {
// The value must have wrapped around.
rawPlaybackHeadWrapCount++;
}
lastRawPlaybackHeadPosition = rawPlaybackHeadPosition;
return rawPlaybackHeadPosition + (rawPlaybackHeadWrapCount << 32);
}
/**
* {@link AudioTrack#getPlaybackHeadPosition()} returns a value intended to be interpreted as an
* unsigned 32 bit integer, which also wraps around periodically. This method returns the playback
* head position as a long that will only wrap around if the value exceeds {@link Long#MAX_VALUE}
* (which in practice will never happen).
*
* @return The playback head position, in frames.
*/
private long getPlaybackHeadPosition() {
AudioTrack audioTrack = Assertions.checkNotNull(this.audioTrack);
if (stopTimestampUs != C.TIME_UNSET) {
// Simulate the playback head position up to the total number of frames submitted.
long elapsedTimeSinceStopUs = (SystemClock.elapsedRealtime() * 1000) - stopTimestampUs;
long framesSinceStop = (elapsedTimeSinceStopUs * outputSampleRate) / C.MICROS_PER_SECOND;
return Math.min(endPlaybackHeadPosition, stopPlaybackHeadPosition + framesSinceStop);
}
int state = audioTrack.getPlayState();
if (state == PLAYSTATE_STOPPED) {
// The audio track hasn't been started.
return 0;
}
long rawPlaybackHeadPosition = 0xFFFFFFFFL & audioTrack.getPlaybackHeadPosition();
if (needsPassthroughWorkarounds) {
// Work around an issue with passthrough/direct AudioTracks on platform API versions 21/22
// where the playback head position jumps back to zero on paused passthrough/direct audio
// tracks. See [Internal: b/19187573].
if (state == PLAYSTATE_PAUSED && rawPlaybackHeadPosition == 0) {
passthroughWorkaroundPauseOffset = lastRawPlaybackHeadPosition;
}
rawPlaybackHeadPosition += passthroughWorkaroundPauseOffset;
}
if (Util.SDK_INT <= 29) {
if (rawPlaybackHeadPosition == 0
&& lastRawPlaybackHeadPosition > 0
&& state == PLAYSTATE_PLAYING) {
// If connecting a Bluetooth audio device fails, the AudioTrack may be left in a state
// where its Java API is in the playing state, but the native track is stopped. When this
// happens the playback head position gets stuck at zero. In this case, return the old
// playback head position and force the track to be reset after
// {@link #FORCE_RESET_WORKAROUND_TIMEOUT_MS} has elapsed.
if (forceResetWorkaroundTimeMs == C.TIME_UNSET) {
forceResetWorkaroundTimeMs = SystemClock.elapsedRealtime();
}
return lastRawPlaybackHeadPosition;
} else {
forceResetWorkaroundTimeMs = C.TIME_UNSET;
}
}
if (lastRawPlaybackHeadPosition > rawPlaybackHeadPosition) {
// The value must have wrapped around.
rawPlaybackHeadWrapCount++;
}
lastRawPlaybackHeadPosition = rawPlaybackHeadPosition;
return rawPlaybackHeadPosition + (rawPlaybackHeadWrapCount << 32);
}
/**
* {@link AudioTrack#getPlaybackHeadPosition()} returns a value intended to be interpreted as an
* unsigned 32 bit integer, which also wraps around periodically. This method returns the playback
* head position as a long that will only wrap around if the value exceeds {@link Long#MAX_VALUE}
* (which in practice will never happen).
*
* @return The playback head position, in frames.
*/
private long getPlaybackHeadPosition() {
AudioTrack audioTrack = Assertions.checkNotNull(this.audioTrack);
if (stopTimestampUs != C.TIME_UNSET) {
// Simulate the playback head position up to the total number of frames submitted.
long elapsedTimeSinceStopUs = (SystemClock.elapsedRealtime() * 1000) - stopTimestampUs;
long framesSinceStop = (elapsedTimeSinceStopUs * outputSampleRate) / C.MICROS_PER_SECOND;
return Math.min(endPlaybackHeadPosition, stopPlaybackHeadPosition + framesSinceStop);
}
int state = audioTrack.getPlayState();
if (state == PLAYSTATE_STOPPED) {
// The audio track hasn't been started.
return 0;
}
long rawPlaybackHeadPosition = 0xFFFFFFFFL & audioTrack.getPlaybackHeadPosition();
if (needsPassthroughWorkarounds) {
// Work around an issue with passthrough/direct AudioTracks on platform API versions 21/22
// where the playback head position jumps back to zero on paused passthrough/direct audio
// tracks. See [Internal: b/19187573].
if (state == PLAYSTATE_PAUSED && rawPlaybackHeadPosition == 0) {
passthroughWorkaroundPauseOffset = lastRawPlaybackHeadPosition;
}
rawPlaybackHeadPosition += passthroughWorkaroundPauseOffset;
}
if (Util.SDK_INT <= 29) {
if (rawPlaybackHeadPosition == 0
&& lastRawPlaybackHeadPosition > 0
&& state == PLAYSTATE_PLAYING) {
// If connecting a Bluetooth audio device fails, the AudioTrack may be left in a state
// where its Java API is in the playing state, but the native track is stopped. When this
// happens the playback head position gets stuck at zero. In this case, return the old
// playback head position and force the track to be reset after
// {@link #FORCE_RESET_WORKAROUND_TIMEOUT_MS} has elapsed.
if (forceResetWorkaroundTimeMs == C.TIME_UNSET) {
forceResetWorkaroundTimeMs = SystemClock.elapsedRealtime();
}
return lastRawPlaybackHeadPosition;
} else {
forceResetWorkaroundTimeMs = C.TIME_UNSET;
}
}
if (lastRawPlaybackHeadPosition > rawPlaybackHeadPosition) {
// The value must have wrapped around.
rawPlaybackHeadWrapCount++;
}
lastRawPlaybackHeadPosition = rawPlaybackHeadPosition;
return rawPlaybackHeadPosition + (rawPlaybackHeadWrapCount << 32);
}