Question

此代码适用于在iOS 8.4中循环播放MusicTrack，但在使用MusicPlayerSetSequence

设置序列时将停止iOS 9.0下的应用程序

var loopInfo = MusicTrackLoopInfo(loopDuration: 1.0,numberOfLoops: 0)
            MusicTrackSetProperty(track, UInt32(kSequenceTrackProperty_LoopInfo), &loopInfo, UInt32(sizeofValue(loopInfo)))

还有另一种方法让音轨在iOS 9中循环播放吗？

Answer 1

其他人遇到了类似的问题：https://forums.developer.apple.com/thread/9940当前解决方法的一般想法是，一旦到达音轨的末尾，将播放标记设置回0。

例如，在您用于启动音乐播放器的方法中使用此功能：

MusicTrack track = NULL;
MusicTimeStamp trackLen = 0;
UInt32 trackLenLen = sizeof(trackLen);
//Get main track
MusicSequenceGetIndTrack(musicSequence, 0, &track);
//Get length of track
MusicTrackGetProperty(track, kSequenceTrackProperty_TrackLength, &trackLen, &trackLenLen);
//Create UserData for User Event with any data
static MusicEventUserData userData = {1, 0x09};
//Put new user event at the end of the track
MusicTrackNewUserEvent(track, trackLen, &userData);
//Set a callback for when User Events occur
MusicSequenceSetUserCallback(musicSequence, sequenceUserCallback, musicPlayer);

然后你可以有一个回调函数：

static void sequenceUserCallback(void *inClientData,
                             MusicSequence             inSequence,
                             MusicTrack                inTrack,
                             MusicTimeStamp            inEventTime,
                             const MusicEventUserData *inEventData,
                             MusicTimeStamp            inStartSliceBeat,
                             MusicTimeStamp            inEndSliceBeat)
{
    [[NSOperationQueue mainQueue] addOperationWithBlock:^ {
        MusicPlayerSetTime((MusicPlayer) inClientData, 0.0);
    }];
}

将播放器设置为零。

如何让AudioToolbox MusicTrack在iOS 9.0中循环？

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