Deleting tempo events from AKSequencer

Question

I need to delete all tempo events from an AKSequencer instance but I can't find a way to do it.

I tried to use the clearRange() method as shown below but I'm not sure it is the right way because it won't work:

var sequencer = AKSequencer()

// successfully adding a few tempo events with addTempoEventAt(tempo bpm: Double, position: AKDuration)

...

// trying to remove them

let sequenceLength = sequencer.length
sequencer.clearRange(start: AKDuration(beats: 0.0), duration: sequenceLength)

Is there something I am missing?

Answer 1

Unfortunately clearRange() removes note events and meta events but, as you observed, it does not remove tempo events (the next version of the docs will make this explicit - thank you for catching this). AKSequencer has a private clearTempoEvents method called internally by the setTempo() method, so you can use setTempo() to clear all the existing tempo events. Of course, after removing the existing tempo events, this will also add a new tempo event at the start of the sequence with the tempo you include as an argument.

So it won't exactly give you a sequence with no tempo events - but a sequence needs a tempo and with no tempo events it will default to 120 - so forcing you to be explicit about the starting tempo isn't such a bad thing. Anyway, unless you really need for there to be absolutely no tempo events, setTempo() should do the trick for clearing all existing tempo events in the sequence.